Specialized english in food technology

3 Research approaches The retention of ascorbic acid is often used as an estimate for the overall nutrient retention of food products.4,5 Ascorbic acid is by far the least stable nutrien

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Specialized English in Food Technology

NHA TRANG UNIVERSITY Faculty of Food Technology

Van Tang Nguyen, PhD

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 Introduction to subject

 Basic concepts and definitions

 Special topics in food technology

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Special topics in food technology

1 Tropical products: tea, coffee, cocoa, cashew and pepper

2 Fruits and vegetables

3 Fermented products: wine, beer, beverages and other foods

4 Milk and milk-originated products

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[1] International Food Information Service 2009 Dictionary of Food Science and Technology (second edition) Wiley-Blackwell.

-Việt NXB Khoa học và Kỹ thuật.

[4] Nguyen, V T (Ed) 2017 Recovering bioactive compounds from agricultural wastes John Wiley & Son, UK & USA.

[5] Other references suggest by lecturer: Books, articles, websites,…

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Tea, Coffee, and Cocoa

L Diby, J Kahia, and C Kouame´, World Agroforestry Centre (ICRAF), Abidjan, Ivory Coast

E Aynekulu, World Agroforestry Centre (ICRAF), Nairobi, Kenya

Introduction

Tea, coffee, and cocoa are cultivated for their young leaves,

cherries, and beans, respectively, from which popular

bever-ages are made and consumed worldwide In addition to

being used as beverage, cocoa is essentially consumed as

chocolate confectionery products The stimulant properties

and medicinal values of these beverages are recognized since

the ancient times These crops are among the most important

agricultural commodities worldwide Tea is the most popular

beverage, and it is consumed by 65% of the world’s

popula-tion, while coffee ranks second with about 2 billion cups

consumed daily Nearly 4 kg cocoa bean equivalent is

consumed per capita annually in developed countries In

2012, the production of processed tea, green coffee, and

cocoa beans was 4.8, 8.8, and 5.0 million MT, respectively.

This production occurs largely in the developing world

(with the exception of tea in China), while the consumption

happens mainly in the developed economies For each of

these commodities, more than 50% of the production is in

only three countries, but unlike other products such as crude

oil the market price is regulated by consumption countries.

The economy of many growing countries depends heavily

on the earnings from these crops which support directly or

indirectly millions of people in both producing and

consuming countries.

Tea, coffee, and cocoa originated from Asia, Africa, and

South America regions, respectively They have been

domesti-cated over time and selected for different production

environ-ment and constraints Currently, the production takes place

essentially within 20 ! N and 20 ! S of the equator in different

climate conditions ( Figure 1 ) They are perennial trees or

shrub crops that can remain economically viable on the

same land for 30–50 years after planting for cocoa and coffee,

and more than 100 years for tea The production system is

extensive and dominated by smallholder farms It is also

char-acterized by the monocropping practices that raise some

envi-ronmental concerns The yields are very variable worldwide

due to different environment conditions and management

practices.

This article is a summary of basic knowledge on the origin

and ecology, the growth and development, the different

prop-agation methods, and the management practices for each of

these crops.

Tea

Historic and Botany

Tea (Camellia sinensis (L.) O Kuntze) is believed to have

origi-nated from the high regions of Southwest China, Myanmar,

and Northeast India These areas are characterized by monsoon

dry winter in the other hand Tea was discovered in China about 5000 years ago, and it was ﬁrst consumed as medicinal drink and later on as a beverage Its consumption became popular in the seventeenth century when British settlers introduced it in India Currently, tea is produced in more than

50 countries in the world It belongs to the family Camelliaceae and to the genus Camellia which accounts for more than 200 species Cultivated tea plants are hybrids of

C sinensis and C assamica In its natural habit, C sinensis is

an evergreen shrub of 1–2 m tall with hard, thick, and leathery leaf C assamica is a small tree of 10–15 m tall with broadly elliptic leaf blade of 8–20 cm long and 3.5–7.5 cm wide.

C sinensis is diploid (2n ¼ 2x ¼ 30) while C assamica is loid (2n ¼ 3x ¼ 45).

trip-Ecology

Tea is adapted to a wide range of growing conditions including altitudes ranging from sea level to about 2800 m a.s.l and temperatures varying from #12 to 40 ! C while optimal temperature ranges from 18 to 20 ! C C sinensis is more tolerant to high altitude and low temperature, while hot and humid climate are more suitable for C assamica The rainfall range is between 900 and 6000 mm, while optimal rainfall uniformly distributed over the year is about 1600 mm The ideal relative humidity is within 70–90% The best soil should be porous, well drained, with pH of 4.5–5.5 although tea can accommo- date pH between 3.3 and 6.

Growth and Development

Shoot growth and development are the main component of yield in tea Shoot growth is characterized by three chrono- logical stages starting with a slow enlargement of the axillary bud and the release and development of the leaf primordial This stage is followed by leaf unfolding during which shoots extend and the leaves develop During this second stage, the number of shoots increases with soil fertility level, and each shoot harvested replaced itself by 1.1–1.6 new shoots The third stage corresponds to the dormancy of the terminal bud The duration of the first two stages is variety and environment specific The flowers are generally white, occasion- ally with pale pink pigmentation and are borne singly or

in pairs in the cataphyllary axils Tea crops begin to fruit 5–6 years after planting, and each fruit contained two to three seeds.

Propagation

Tea is propagated mainly through cuttings and seeds Cuttings are harvested from healthy vigorous growing plants that have not been pruned for 4–9 months, and usually the middle

Author's personal copy

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Figure 1 a) Tea, b) coffee, and c) cocoa production countries in the world (FAO, 2012).

Tropical Agriculture j Tea, Coffee, and Cocoa 421

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one healthy leaf The best period to collect and keep them fresh

is on cool and cloudy day The cuttings are planted straight or

slightly slanted so that the leaf does not touch the soil They are

then transplanted to the ﬁeld about 12 months later once they

are rooted Seeds are planted at a depth of 1.5–2.5 cm, with the

‘eye’ of the seed pointing downward They sprout within one or

several months after planting.

Crop Improvement and Management

The initial work of tea breeding focused on yield improvement.

However, the lack of information on the defense mechanism

and stress tolerance has prevented progress on selection for

pest- and disease-resistant cultivars.

Tea production is constrained by more than 100 fungal

diseases, among which Camellia dieback and canker are the

most serious and are caused by Glomerella cingulata Camellia

ﬂower blight caused by Ciborinia camelliae is another serious

fungal disease A number of viral, bacterial, nematode, and

numerous pests also pose major production challenges To

mitigate these challenges, an integrated pest management

(IPM) approach is recommended.

N is the key mineral nutrient for tea being a leaf crop Tea is

sensitive to the source of N with ammonium source promoting

growth and development while the nitrate source inhibits

growth Sulfur and trace elements like Zn, B, and Mo can be

applied on needed basis.

Pruning is one of the most important operations, next to plucking, which directly determines the productivity of tea It prevents top growth and stimulates growth of the bush for comfortable plucking with renewed and vigorous branching pattern It is important to establish a well-developed primary frame and branch system to ensure a complete ground cover

as early as possible.

Coffee

History and Botany

All commercial coffee species originated from Africa and belong to the genus Coffea The high-quality C arabica originated from the rain forests in the southwestern highlands of Ethiopia C canephora varieties including robusta coffee, grow

at lower altitude and perform well in the equatorial, warm, and wet tropics, and they occur naturally in the western Congo basin There exist also two additional minor coffee species,

C liberica and C excelsa that are genetically considered as

a single complex C liberica originates from West Africa around Liberia while C excelsa comes from the drier parts of Central Africa, mainly Central African Republic Coffee belongs to the family Rubiaceae, which has about 500 genera and more than 6000 species The genus Coffea L comprises more than

100 species, of which only two (C arabica and C canephora) are commercially cultivated C liberica is also cultivated in

Figure 1 (continued).

422 Tropical Agriculture j Tea, Coffee, and Cocoa

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a small scale to satisfy local consumption Almost all the coffee

species are diploid (2n ¼ 2x ¼ 22) and generally

self-incompatible except C arabica which is a natural allotetraploid

(2n ¼ 4x ¼ 44) self-fertile species.

Ecology

Coffee can be cultivated from a few meters to up to 2000 m

a.s.l., although higher altitudes generally produce a better

quality crop Temperature is one of the limiting factors for

coffee and the optimum range is between 15 ! C and 24 ! C

Rain-fall is the second most important growth limiting factor with

range between 1000 and 2000 mm However, in lower rainfall

areas, irrigation is a common practice The best soil should be

well drained, deep, and rich in organic matter with pH range

from 5.4 to 6.0.

The growth and development in coffee is divided into

vegeta-tive and reproducvegeta-tive phases There are two distinct structures

in this phase, the root and the shoot systems The root system

is composed of the vertical and lateral roots that grow parallel

to the ground and the tap root that grows vertically down the

ground The density and length of roots of most important

species are age dependent and vary with the planting densities,

soil characteristics, and cultural practices The shoot system has

two main components, a main vertical trunk (orthotropic) and

primary, secondary, and tertiary horizontal branches

(plagio-tropic) This phase includes ﬂowering, fruit development, and

ripening Three to four years after planting, ﬂowers grow in

clusters in the axils of the coffee leaves After fertilization, the

subsequent fruit development is organized in ﬁve stages: (1)

pinhead that spreads from 6 to 10 weeks after blossoming,

(2) rapid swelling that takes place from 10 to 17 weeks, (3)

sus-pended and slow growth that lasts about 2 weeks after the rapid

swelling stage, (4) endosperm ﬁlling occurring 19–28 weeks,

and (5) ripening stage that extends from 8 to 12 months after

ﬂowering.

Propagation

Coffee is propagated through seeds, cuttings, grafting, and

tissue culture For cuttings, the non-ligniﬁed orthotropic shoots

with one node are harvested early in the morning when the

relative humidity is comparatively high The cuttings are kept

in propagator for rooting and then potted in nursery containers

ﬁlled with compost for 2–3 months before replanting in the

farms Grafting has been used to graft C arabica species (which

have a root system susceptible to nematodes) on C liberica

(which is resistant) The best grafting methods are simple cleft

grafting, top grafting, side grafting, and shield grafting that are

used to propagate natural hybrids and clones With seeds, in

order to reduce the risk of cross pollination, fully ripened

berries from trees growing in the center of a block are used.

They are harvested, pulped, and dried for immediate

germina-tion on sand bed before transplanting them in polybags

con-taining appropriate substrate For conservation, the seeds are

further dried to a moisture content of about 41% and can be

kept viable for more than 2 years in airtight polythene bags

at 15 ! C Tissue culture is used to rapidly multiply elite hybrids and clones Coffee plants can be regenerated using three general procedures, namely, axillary bud branching, shoot organogenesis, and somatic embryogenesis (SE).

Coffee breeding is largely restricted to the two species,

C arabica and C canephora, that dominate world coffee tion However, C liberica has contributed useful characters to the gene pool of C arabica and C canephora through natural and artiﬁcial interspeciﬁc hybridization Initial breeding objec- tives were to increase productivity and adaptability to local conditions The appearance of coffee leaf rust (Hemileia vastatrix Berk and Br) in epidemic scale in Southeast Asia between 1870 and 1900 changed the breeding focus worldwide with focus on disease resistance Although conventional breeding is mainly used for coffee improvement, it is a long process involving selection, hybridization, and progeny evaluation In recent years, the coffee genome has been sequenced using high- throughput technology and this has substantially shortened the breeding process Coffee grows well under shade, and naturally occurring varieties can only be cultivated under shade trees

produc-as it wproduc-as practiced in the earlier years However, the releproduc-ase of new full-sun hybrids with high yields circumvented the use

of shade resulting in quality depreciation, loss of biodiversity, and other environmental changes.

Major coffee pests and diseases are outlined in Table 1 The recommended disease management options include the use of tolerant varieties, chemical and biological control as well as best cultural practices.

Coffee berries removed proportionally more nutrients compared to the harvested products of cocoa and tea K and

N are the major nutrients required in coffee production K contributes to fruit development while N is necessary for vegetative growth P uptake is less important, but it is essential for root, ﬂower, and fruit growth and development Other nutrients such as B and Zn are applied on needed basis.

For optimal growth and productivity of coffee, the trees need to be pruned Pruning helps to establish a strong fra- mework, maintain the ideal crop leaf ratio and rejuvenate the tree There are basically two pruning systems, namely single

Table 1 Major coffee pests and diseases, causal agents, and prevailing areas

Pests and diseases Causal agents Prevailing areas Coffee leaf rust

Africa, Asia, and South America

Stem borers (insect) Coleoptera:

Cerambycidae Africa, Asia, and SouthAmerica Bacterial blight

(bacteria) Pseudomonassyringae

Africa Coffee berry borer

(insect) Hypothenemushampei

Africa, South and Central America

Coffee leaf miner (insect) Leucoptera coffeella All production areas

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stem (single trunk) and double stem (multiple trunk) The

fundamental difference is the number of stems and branches

maintained on the trees.

Cocoa

History and Botany

Cocoa (Theobroma cacao L.) is native to South (Amazon forest)

and Central Americas It has been known and cultivated by the

Mayas and the Atzeques for about 2000 years The crop was

ﬁrst moved from its area of origin and expanded throughout

Mexico by the Atzeques While the Spanish settlers discovered

the crop in the Caribbean in the sixteenth century, cocoa was

cultivated as cash crop only in the seventeenth century It was

introduced in West Africa through Sao Tome and Principe in

1822 by the Portuguese settlers The genus Theobroma belongs

to the order Malvales and to the family Malvaceae (previously

Sterculiaceae) Theobroma includes 22 species of which only T.

cacao and T grandiﬂorum have economic values with T cacao

being by far the most important of the two T cacao is both

self-incompatible and self-compatible depending on the

geno-types, and it is diploid (2n ¼ 20).

Ecology

Cocoa is an evergreen understory tree with a height of up to ca.

9–10 m in its natural habit, although cultivated cocoa are

managed at a shorter height While cacao can grow under

temperature varying from 20 to 30 ! C, the optimum growth

occurs under 25–28 ! C The ideal rainfall range varies from

1500 to 3000 mm, which should be well distributed

throughout the year with less than 3 months of dry season.

Relative humidity is a major limiting factor in cocoa

produc-tion and RH above 80% is required Cocoa can grow on

a variety of soil types; however, the best soil should be deep,

light with sufﬁcient organic matter and pH varying between

5.5 and 8.

T cacao has nine principal growth stages as per the BBCH

(Bio-logische Bundesantalt, Bundessortenamt und Chemische

Industrie, Germany) growth classiﬁcation scale Growth stage

0 includes seed germination where the seedling exhibits a fast

growth of the tap root on which rootlets are formed These

rootlets develop further into lateral roots for nutrients

acquisi-tion Growth stage 1 comprises leaf development on both

prin-cipal stem and lateral branches Leaf growth is characterized by

a leaf ﬂush where about 10 leaves initiate simultaneously and

expand for about 40 days before the next ﬂush Growth stage

2 includes the elongation of the principal stem and the

devel-opment of jorquette of lateral branches and chupons that occur

1–2 years after planting Growth stage 3 consists in the

elonga-tion of the lateral branches The growth stage 4 in the BBCH

scale does not apply to cocoa, but only to cereals Growth

stages 5 and 6 entail the emergence of the inﬂorescence and

ﬂowering, respectively A cocoa tree can produce up to

120 000 ﬂowers per year, from which only 0.5–5% reach

matu-rity Growth stages 7 and 8 correspond to the development

of fruit and seed maturity Growth stages 7 and 8 last 150–200 days after anthesis The last growth phase (growth stage 9) is the senescence.

Propagation

Cocoa is mainly propagated by generative and vegetative methods With the generative method, cocoa seeds are directly sown in the ﬁeld or raised in nurseries for about 6 months before transplanting in the ﬁeld It is recommended that seeds are produced from known parentage to limit genetic variation

in the progenies The vegetative propagation is suitable for genetically heterogenous planting materials It includes mainly cuttings, grafting, and SE Cuttings are collected from young fan branches or orthotropic shoots and are rooted in potting substrates before transplanting them on farms Grafting consists of using scions from elite cocoa plant materials and grafting them on young cocoa seedlings or mature trees, referred to as rootstocks ( Figure 2 ) SE is a tissue culture cloning method that uses plant parts (immature ﬂowers for cocoa) to regenerate plantlets.

Cocoa breeding work has been focused on yield and disease resistance This has been achieved by crossing materials from the three genetic groups ‘Criollo,’ ‘Forastero,’ and their hybrids

‘ Trinitario.’ It is expected that the recent reclassiﬁcation of cocoa into 10 genetic groups and the mapping of cocoa genome will accelerate the selection of plant materials adapted to current production challenges.

Cocoa is susceptible to a number of pests and diseases that are location speciﬁc and cause an estimated loss of 30%–40%

of world’s production The causal agents of the major pests and diseases are fungi, virus, and insects ( Table 2 ) Cocoa swollen shoot virus is one of the main threats to cocoa production in West Africa The crop is also susceptible to many obligate hemi- parasitic plants The pests and diseases management options are similar to those recommended for coffee.

Figure 2 Elite cocoa clones grafted on mature trees used as rootstocks.

424 Tropical Agriculture j Tea, Coffee, and Cocoa

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Leaf lamina is the major sink for nutrients in cocoa, and the

amounts of nutrient stored by the plant decreases in the

following order: K > N > Ca > Mg > P > Mn > Zn In

well-established farms, cocoa litter decomposition can produce

enough N to supply the crop needs This endogenous N should

be taken into account when designing fertilizer

recommenda-tions for the crop.

Pruning is a common practice in cocoa cultivation not only

for production and sanitation reasons, but also to limit the

growth of the plant.

Acknowledgments

The authors are grateful to Mr Kouassi Jean-Luc who produced the map

(Figure 1), and to Mr Kofﬁ Kouassi who provided us the picture (Figure 2).

See also: Arable Crops: Agricultural Crops; Canopy

Architecture; Field Crops; Growth Analysis, Crops;

Multicropping Crop Diseases and Pests: Bacterial Diseases;

Breeding for Disease Resistance; Fungal and Oomycete

Diseases; Integrated Pest Management: Practice; Integrated

Pest Management: Principles; Plant Pathology, Principles; Viral

Diseases Horticulture Production and Quality: Orchard Crops.

Plant Breeding and Genetics: Plant Breeding, Practice; Plant

Breeding, Principles Plant Cells: Leaf Development Plant

Nutrition: Deﬁciency Diseases, Principles; Growth and Function

of Root Systems; Mineral Uptake Postharvest Biology:

Ripening Reproduction and Biodiversity: Fertilization; Flower

Development; Gametophytic Self-Incompatability; Pollination;

Sporophytic Self-Incompatability Tissue Culture: Clonal

Propagation, Forest Trees; General Principles of Tissue Culture;

Somatic Embryogenesis Tropical Agriculture: Oil Palm;

Plantation Crops and Plantations; Rubber; The Coconut Palm.

Further Reading

Carr, M.K.V., Lockwood, G., 2011 The water relations and irrigation requirements of

cocoa (Theobroma cacao L.): a review Exp Agric 47 (4), 653–676.

Carr, M.K.V., 2010a The role of water in the growth of the tea (Camellia sinensis L.)

crop: a synthesis of research in Eastern Africa 1 Plant water relations Exp Agric.

Niemenak, N., Cilas, C., Rohsius, C., et al., 2010 Phenological growth stages of cacao plants (Theobroma sp.): codiﬁcation and description according to the BBCH scale Ann Appl Biol 156, 13–24.

Owuor, O.P., Kamau, D.M., Jondiko, E.O., 2010 The inﬂuence of geographical area of production and nitrogenous fertiliser on yields and quality parameters of clonal tea.

J Food Agric Environ 8 (2), 682–690.

Peter, K.V., Kurian, A., Chopra, V.L., 2003 Plantation crops and plantations In: Murphy, D.J., Murray, B.G., Thomas, B (Eds.), Encyclopedia of Applied Plant Sciences, 3-volume Set, ﬁrst ed Elsevier Science, Burlington,

pp 956–960.

Ploetz, R.C., 2006 Cocoa diseases: important threats to chocolate production worldwide Annual Meeting of the American Phytopathological Society Joint with the Canadian Phytopathological Society and the Mycological Society of America, July 30, 2006 Quebec City, Quebec, Canada.

Tscharntke, T., Clough, Y., Bhagwat, S.A., et al., 2011 Multifunctional shade tree management in tropical agroforestry landscapes – a review J Appl Ecol http:// dx.doi.org/10.1111/j.1365-2664.2010.01939.x

Vos, J.G.M., Ritchie, B.J., Flood, J., 2003 Discovery Learning about Cocoa An Inspirational Guide for Training Tacilitators CABI Bioscience, UK.

Willson, K.C (Ed.), 1999 Crop Production Science in Horticulture 8: Cocoa, Coffee and Tea CABI International, Wallingford.

Relevant Websites

http://www.worldagroforestry.org/treesandmarkets/inaforesta/ – Cocoa Agroforestry.

http://faostat3.fao.org – FAO Database.

www.internationalcamellia.org – International Camellia Society.

www.icco.org – International Cocoa Organization.

www.ico.org – International Coffee Organization.

www.tocklai.net – Tea Research Association India.

http://www.tearesearch.or.ke – Tea Research in Kenya.

Table 2 Major cocoa pests and diseases, causal agents, and prevailing areas

Phytophthora pod rot (fungus) P palmivova, P megakarya, P capsici, P citrophthora All production regions depending on causal agents

Vascular streak dieback (fungus) Oncobasidium theobromae Paciﬁc, South East Asia

Mirids or capsids (insect) Sahlbergella singularis, Distantiella theobromae,

Bryocoropsis; Odoniella, Boxiopsis madagascariensis, Afropeltis; Helopeltis, Pseudodoniella, Platyngomiriodes, Monalonion

All production regions depending on causal agents

Stem borer (insect) Eulophonotus myrmeleon, Pantorhytes West Africa, Paciﬁc

Termite (insect) Cryptotermes havilandi, Coptotermes sjostedti,

Schedorhinotermes putorius, Macrotermes bellicosus Africa, South America, Paciﬁc

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 Fermented foods contain microorganisms, such

as bacteria and yeasts, that use the nutrients in the food as an energy source

 The result is a transformation of the original food into one with organic acids and other compounds beneficial for health

 Fermented foods have a unique flavor that is tangy, pungent, and aromatic

 There are dozens of fermented foods ranging from drinks to side dishes

 These bacteria are able to digest food, fight off

Homemade kombucha, which is

a fermented tea beverage

Pickles are fermented cucumbers

July 2017

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Fermentation is an ancient practice used to preserve food In

tradition-al fermentation, stradition-alt plays a crucitradition-al role in creating an environment that is conducive towards good bacteria and preventing growth of harmful pathogens

Integrative medicine is a holistic approach to healthcare, that takes into account the whole person, including body and mind in the healing process

A major component of integrative medicine is gut health and its relationship to diseases

Global Cultures

Integrative Medicine

Science of Probiotics

Probiotics have been shown to contribute to a proper

microbial balance, which helps to support the immune

system and reduce inflammation in the gut

Fertile Crescent

Region

Garii from West Africa

Intentional fermentation is thought to have first occurred in

the Fertile Crescent area of the Middle East in 6000 B.C Since

then virtually every culture has at least one fermented food:

kimchi from Korea; chutneys from India; and garii, fermented

cassava, from West Africa

Probiotic consumption may help to reduce complications relating to the gastrointestinal tract including irritable bowel syndrome (IBS), ulcerative colitis, Crohn’s disease, and diarrhea

Registered Dietitians working with an integrative medicine team

often encourage consuming probiotics, preferably though food, to

reintroduce helpful bacteria and thus facilitate optimal digestive

function The connection between fermented foods and health can be

traced back to both ancient Rome and China (Reference #1)

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Prebiotics are not bacteria themselves, but natural, non-digestible

food components that helpful bacteria can use as an energy source

and proliferate from Prebiotics thus improve digestive health, and

also may enhance calcium absorption

Kefir is fermented by both bacteria and yeast that are present together

as “kefir grains” which are a gelatinous culture It’s important to shake the bottle well to distribute the grains and make the kefir creamy, smooth, and easy to drink

Consuming fermented dairy products may lower the risk of developing high blood pressure (Reference #1)

Kefir and yogurt are both

fermented milk products

that contain probiotics

that facilitate optimal gut

health However, the

pro-cess by which these foods

are fermented differs

Yogurt is fermented by

bacteria that can digest

the lactose sugar in milk

Prebiotics

Probiotics

Page 3 Fermented Foods

Kefir vs Yogurt

Kefir Grains

A Selection of Commercial Kefir

Sources of prebiotics in foods include bananas, whole wheat foods, and vegetables such as leeks, asparagus, and artichokes (Reference #2)

Probiotics are helpful bacteria that naturally occur in the gut that digest and breakdown food They give a boost to the current bacteria and help to balance gut flora Probiotics can improve gastrointestinal health and immunity, as well as prevent specific allergy symptoms

Food sources of probiotics include fermented dairy products such as kefir, yogurt, and aged chees-

es Non-dairy fermented foods that contain probiotics include

kimchi, sauerkraut, miso, and tempeh (Reference #2)

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Cucumbers are a common vegetable of choice to pickle, but other vegetables can work as well such as onions, peppers, and beets

Pickles are a source of probiotics, which can help to improve digestion and enhance the availability of nutrients in our foods and drinks

Lacto-fermentation is a process in which foods are submerged in salt water and are fermented by lactobacillus bacteria

Lactic acid bacteria provide benefits to human health, such as improved digestion of lactose and prevention of intestinal infections

Kimchi may have the ability to improve mental functioning due to increasing the expression of a gene responsible for regulating psychological stress and anxiety (References #3 and #4)

Vinegar is said to originate as far back as 400 B.C

in Greece, when Hippocrates used it as a medicinal treatment

Apple cider vinegar has subtle fruit notes that can add flavor to salad dressings and sauces

The process begins by crushing apples into juice, adding yeast, and letting it ferment in barrels

Research suggests apple cider vinegar can help to control blood sugars after

a sugary meal Also, apple cider vinegar has polyphenols, a potential cancer-fighting nutrient (Reference #7)

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Kombucha is a sugared tea that has been fermented via a

symbiotic culture of bacteria and yeast, or a SCOBY for short

The SCOBY is a mat-like pellicle, or tea fungus, that feeds off

the sugar and replicates each fermentation cycle

It’s thought that kombucha originated in China some 2000

years ago

In terms of flavor, Kombucha is mildly acidic, fruity, sour and effervescent

Although kombucha has flavor on its own, it comes in various other flavors with fruit juices and herbs like ginger added for a more dynamic taste

What is Kombucha?

Where to Purchase Kombucha

Kombucha Benefits

Kombucha has been shown to help with digestion,

prevent microbial infections, and even have a positive

influence on cholesterol levels

Kombucha is made with green, black, or oolong tea, which have beneficial antioxidants Antioxidants are helpful compounds that stop free radicals which are harmful

compounds that cause cell damage

Kombucha tea actually has more antioxidants than regular tea due to the acidic environment and enzymes from the yeast and bacteria culture that break large antioxidants into many small antioxidants (Reference #5)

Kombucha can be found in most grocery stores in the organic section

with the refrigerated foods

A local company called Unity Vibration makes hand-crafted, artisanal

kombucha teas

Visit unityvibrationkombucha.com for more information

and where to find stores that sell their product near you

Where to Purchase Kombucha

GT’s/Synergy Kombucha

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Making kombucha is rather quick and simple

However, you will need to obtain a SCOBY

from a friend to start a new batch, or purchase

one online Other ingredients are tea

(black, green, or oolong), sugar, and a glass vessel

Directions

1) Fill vessel with 2 cups of plain kombucha tea if

available to kick start the brew

2) Boil 1 gallon of water, add 1 cup of sugar, and wait

till it dissolves

3) Steep 8 teabags for 5 minutes in the water

4) Let cool to room temperature and then add to vessel

5) Carefully slide SCOBY in the vessel and store with cover that allows air to pass through (paper towel or cheesecloth)

6) Wait and let ferment for 7-10 days

7) Bottle and enjoy! (Kombucha is stable for 1 month in refrigerator.)

Some quick notes about home-brewing

-Check for any growth of mold; is rare but sometimes happens if contamination occurs

-The SCOBY will replicate each cycle, so dispose of the old one on the bottom, and use the new one

on top for the next batch

Flavors should be added to the individual bottles to prevent any contamination of the SCOBY and vessel

Try adding a touch of fruit juice such as orange juice or ate juice for a tropical flavor Alternatively, try adding actual fruit, such as blueberries and strawberries, and filter before serving

pomegran-Cut up a few ginger root slices and mint leaves and let sit with the kombucha overnight to give it a little spice

Kombucha Recipe

Flavor Ideas

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Sauerkraut is a traditional fermented cabbage dish

from Germany commonly served as a side or as a

condiment on bratwurst

Directions

1) Slice 2 large cabbages and place into a large mixing bowl

2) Add 2 tablespoons of salt and 1 tablespoon of caraway seeds,

mix together

3) Place the mixture into glass canning jars and cover with a

paper towel secured by a rubber band

4) Let ferment in a cool dark place for 3-4 weeks, replace top

with a lid, and enjoy!

Store in refrigerator and eat within 2 months

Sauerkraut Recipe

Strawberry Banana Kefir Smoothie Recipe

Kefir is more liquid and pourable than yogurt, and thus can be used to make smoothies without the addition of milk This is a recipe for a

strawberry banana smoothie, but any fruit in these

proportions will blend well

Directions (Serves 1)

1) Cut 1 large banana into several slices

2) Measure out 1 cup of strawberries, cut off the

leaves, and then slice a few times

3) Measure out 1 cup of plain kefir

4) Place all in a blender, blend till smooth,

and pour into a glass

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Thank you for

Cre-3.) Tamang, J P, et al (2016) Functional properties of

4.) Selhub, E M, et al (2014) Fermented foods, microbiota, and mental health: Ancient practice meets nutritional psychiatry

Journal of Physiological Anthropology , 33 (1), 2

5.) Watawana et al., “Health, Wellness, and Safety Aspects of the Consumption of Kombucha,” Journal of Chemistry, vol

2015, Article ID 591869, 2015

6.) http://www.pbs.org/food/the-history-kitchen/history-pickles/ 7.) http://www.theleangreenbean.com/all-about-apple-cider-

vinegar/

References

Owen Densel Patient Food and Nutrition Services

300 N Ingalls Street NIB NI8E20 Ann Arbor, MI 48109-5407 (734) 936-5147

A special thanks to April Pickrel MS, RDN for her help and guidance in this project

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Journal of the Science of Food and Agriculture J Sci Food Agric 87:930– 944 (2007)

Review

Nutritional comparison of fresh, frozen and

canned fruits and vegetables Part 1 Vitamins

C and B and phenolic compounds

Joy C Rickman, Diane M Barrett and Christine M Bruhn∗

Department of Food Science and Technology, University of California – Davis, Davis, CA 95616, USA

Abstract: The first of a two-part review of the recent and classical literature reveals that loss of nutrients in fresh products during storage and cooking may be more substantial than commonly perceived Depending on the commodity, freezing and canning processes may preserve nutrient value The initial thermal treatment of processed products can cause loss of water-soluble and oxygen-labile nutrients such as vitamin C and the B vitamins However, these nutrients are relatively stable during subsequent canned storage owing to the lack of oxygen Frozen products lose fewer nutrients initially because of the short heating time in blanching, but they lose more nutrients during storage owing to oxidation Phenolic compounds are also water-soluble and oxygen- labile, but changes during processing, storage and cooking appear to be highly variable by commodity Further studies would facilitate the understanding of the changes in these phytochemicals Changes in moisture content during storage, cooking and processing can misrepresent changes in nutrient content These findings indicate that exclusive recommendations of fresh produce ignore the nutrient benefits of canned and frozen products Nutritional comparison would be facilitated if future research would express nutrient data on a dry weight basis to account for changes in moisture.

 2007 Society of Chemical Industry

Keywords: nutrient; fruit; vegetable; canned; frozen; vitamins; phenolic

INTRODUCTION

Fruits and vegetables are colourful, flavourful and

nutritious components of our diets and are often

most attractive and health-promoting when harvested

at their peak maturity Unfortunately, most people

do not have home gardens capable of supplying the

recommended 5 – 13 daily servings year round Many

fruits and vegetables grow only in certain parts of

the world, under specific temperature and humidity

environments, and at particular times of the year In

addition, fruits and vegetables are typically over 90%

water and, once they are harvested, begin to undergo

higher rates of respiration, resulting in moisture loss,

quality deterioration and potential microbial spoilage.

Harvesting itself separates the fruit or vegetable from

its source of nutrients, the plant or tree, and it

essentially uses itself as a source of calories Many

fresh fruits and vegetables have a shelf life of only days

before they are unsafe or undesirable for consumption.

Storage and processing technologies have been

utilised for centuries to transform these perishable

fruits and vegetables into safe, delicious and stable

products Refrigeration slows down the respiration of

fruits and vegetables and allows for longer shelf lives.

Freezing, canning and drying all serve to transform

perishable fruits and vegetables into products that

can be consumed year round and transported safely

to consumers all over the world, not only those located near the growing region As a result of processing, respiration is arrested, thereby stopping the consumption of nutritious components, the loss

of moisture and the growth of micro-organisms The first objective of fruit and vegetable processing is to ensure a safe product, but processors also strive to produce the highest-quality products Depending on how processing is carried out, it may result in changes

in colour, texture, flavour and nutritional quality, the last of which is the subject of the following literature review.

A substantial amount of research literature has been published over the past 75 years reporting the effects of processing, storage and cooking on the nutritional quality of fruits and vegetables Washing, peeling and blanching steps prior to processing are responsible for some loss of water-soluble nutrients However, the thermal processing often associated with canning and pre-freezing blanching treatments

is especially detrimental to heat-sensitive nutrients such as ascorbic acid (vitamin C) and thiamin 1 When used prior to canning, blanching serves to expel air

in the tissue and improve thermal conductivity and packing into the container The primary purpose of

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Nutritional comparison of fresh, frozen and canned fruits and vegetables

blanching prior to freezing is to inactivate naturally

occurring enzymes that may still be active in the

frozen product Blanching is an important preservation

step in the canning and freezing processing of many

vegetables Fruits, on the other hand, are usually

not blanched prior to freezing owing to their delicate

nature and inherent acidity Nutrients may also be lost

through oxidation, especially during heat treatment

and storage Since both unprocessed and processed

fruits and vegetables must undergo some transport

and storage, degradation of some nutrients prior to

consumption is expected Lower temperatures, even

in frozen goods, tend to prolong the shelf life of fruits

and vegetables 2 Additional cooking of the processed

product can also destroy nutrients, although the extent

of degradation is dependent on cooking method,

nutrient and commodity In Part 1 we discuss vitamins

C and B and phenolic compounds Part 2 will look at

vitamin A and carotenoids, vitamin E, minerals and

fibre 3

Research approaches

The retention of ascorbic acid is often used as

an estimate for the overall nutrient retention of

food products.4,5 Ascorbic acid is by far the least

stable nutrient during processing; it is highly sensitive

to oxidation and leaching into water-soluble media

during processing, storage and cooking of fresh,

frozen and canned fruits and vegetables.6,7 Other

vitamins, minerals and bioactive components are more

stable; high retention of certain components, such as

vitamin E, is common during processing, storage and

cooking Retention of nutrients is highly dependent on

cultivar, production location, maturity stage, season

and processing conditions 8 – 14

Despite the wealth of research published,

under-standing nutritional differences between fresh, frozen

and canned foods is complex Researchers often

exam-ine the effects of processing and storage on a single

cultivar by randomly harvesting fruits or vegetables

from the same location to limit variability due to

pro-duction area, harvest time and cultivar While this

enables researchers to directly understand the effects

of thermal processing on a specific commodity, it

does not accurately represent the choice consumers

have at the supermarket At the other extreme, some

researchers simply purchase fresh products from the

grocery store and use these as the raw materials for

processing studies, without adequate information on

cultivar, maturity and production location.

Different cultivars are often used for canned and

frozen products than for those products intended for

fresh consumption, and nutritional differences exist

between cultivars Furthermore, studies examining the

effects of processing on a food may not subsequently

study the effects of storage and cooking on the

same food By the time a consumer consumes fresh

purchased goods, the canned or frozen equivalent may

be nutritionally similar owing to oxidative degradation

of the nutrients during handling and storage of the

fresh product Researchers should simulate conditions

on the known cultivars harvested from selected locations Nutritional qualities also vary according to season and growing location, so individual results may not be representative of yearly averages or regional availability.

Some researchers have approached these problems

by examining the differences in fresh, frozen and canned fruits and vegetables purchased at a retail market Although the cultivars are likely not consistent and the products have undergone different storage and processing conditions, these retail market studies offer

a representation of the nutritional differences between fresh, frozen and canned products that are available to consumers in that location.

Besides variance in methodologies, changes in nutritional data may be reported on a dry weight (DW)

or a wet weight (WW) basis Moisture content often changes during processing, especially during canning with the addition of aqueous media Furthermore, changes in moisture content due to weight loss can occur during storage, the extent of which is dependent on conditions such as relative humidity Measurements of changes in bioactive components

on a wet weight basis may thus be misleading Some researchers avoid this dilemma by comparing results on both bases or by adjusting their wet weight products for content of soluble solids However, many studies still report results only on a wet weight basis, complicating the interpretation of results.

Nutritional guidelines

Despite possible degradation of nutrients during processing, storage and cooking, fruits and vegetables are rich sources of many vitamins and minerals, as well as fibre The United States Food and Drug Administration (FDA) defines a ‘good source’ of a nutrient as one serving of food containing 10 – 19%

of the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) for that nutrient However, nutrient retention data are often reported in units per 100 g rather than per serving Since serving size for labelling depends on commodity, a single serving may be more or less than 100 g.

When interpreting data, it is important to consider intake guidelines for each nutrient, such as the Dietary Reference Intakes (DRIs) used in the USA and Canada and published by the Food and Nutrition Board of the National Academy of Sciences (Table 1) DRIs refer to intake recommendations for various nutrients and include the aforementioned RDA and

AI in addition to Estimated Average Requirement (EAR) and Tolerable Upper Intake Level (UL) EARs are based on the daily requirements of 50% of healthy individuals in a particular group, while RDAs are set slightly higher to meet the needs of most (97 – 98%) individuals When there are insufficient data to set

an EAR for a particular nutrient, such as potassium,

an AI is specified as an approximation Nutrients that may pose health risks above a certain level,

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JC Rickman, DM Barrett, CM Bruhn

Table 1 Dietary Reference Intakes (mg day−1) for healthy adults (www.iom.edu)

Vit C

(RDA)

Thiamin (RDA)

Riboflavin (RDA)

Vit B6(RDA)

Niacin (RDA)

Folate (RDA)

Vit A (RDA)

Vit E (RDA)

Calcium (RDA)

Potassium (AI)

Sodium (AI)

Fibre (AI) RDA or AI 82.5 1.15 1.2 1.3 15 0.40 0.80 15 1000 4.7 1.5 30 EAR 67.5 0.95 1.0 1.2 11.5 0.32 0.56 12 – – – –

RDA, Recommended Dietary Allowance; AI, Adequate Intake; EAR, Estimated Average Requirement.

such as sodium, are assigned a UL In September

2005 the United States Department of Agriculture

(USDA), Agricultural Research Service published a

review of 2001 – 2002 food intake data, finding that

most Americans have significantly lower intakes of

vitamins A, C and E, as well as magnesium, than

the EAR for each nutrient Additionally, although no

EAR is set for vitamin K, fibre, potassium or calcium,

these nutrients may also be consumed in less than

desirable quantities These findings may reflect the

insufficient consumption of fruits and vegetables by

most Americans.

While nutrient intakes vary by location,

inade-quate fruit and vegetable consumption is a worldwide

concern The World Health Organisation (WHO)

estimates that worldwide consumption of fruits and

vegetables is only 20 – 50% of the recommended

daily minimum of 400 g per person (Food and

Agriculture Organisation of the United Nations:

http://www.fao.org/ag/magazine/0606sp2.htm) In fact,

low fruit and vegetable intake is sixth on WHO’s list

of 20 risk factors for mortality worldwide WHO

esti-mates that sufficient fruit and vegetable consumption

could save up to 2.7 million lives annually (WHO:

http://www.who.int/dietphysicalactivity/media/en/

gsfs fv.pdf) Reasons for insufficient fruit and

veg-etable intake vary among different climates, cultures

and countries Postharvest loss due to

perishabil-ity may be up to 50% in some developing nations.

In developed nations where different forms of fruits

and vegetables are plentiful, low intake is sometimes

attributed to consumers’ desire for more convenience

foods.

Health agencies in many countries, including the

USA, support a Five-A-Day goal to encourage

the consumption of fruits and vegetables Although

barriers to consumption vary, the recommendation

to increase consumption of fruits and vegetables

is a global standard The Food and Agricultural

Organisation (FAO) has collaborated with WHO to

lead the Global Fruit and Vegetables Initiative for

Health The first phase of this initiative, 2006 – 2009,

will include support for national action programmes

in up to six pilot countries in developing regions such

as Southern Africa and Latin America.

Government recommendations and current

consumption

In the USA, several different agencies promote the

consumption of all forms of fruits and vegetables.

Human Services and the Department of ture, suggest that both males and females increase their overall fruit and vegetable consumption to nine servings (about 4.5 cups) a day for a 2000 calo- rie diet This is an increase of 50 to over 100% from current consumption These guidelines specif- ically state that all types of fruits and vegetables, including fresh, frozen, canned and dried products, should be consumed to meet dietary recommendations Similarly, the Centers for Disease Control and Prevention state that ‘all fresh, frozen, dried or canned fruits and vegetables count towards the Five-A-Day goal, as long as they don’t have added sugars or fats’ (http://www.cdc.gov/nccdphp/dnpa/5aday/faq/types htm) It is important to note that foodstuffs may only bear the Five-A-Day logo if they meet the FDA requirements for ‘healthy’ food, which places restric- tions on fat, saturated fat, cholesterol and sodium.

Agricul-In particular, sodium levels must be below 480 mg per serving to bear the Five-A-Day logo In general, canned fruits and vegetables meet this requirement (http://5aday.gov/about/pr.html).

The Women, Infants and Children (WIC) gramme seeks to improve the nutritional status of low-income women and their children, in part by providing food packages designed to address their nutritional deficiencies Recent proposed changes to WIC packages include the addition of monthly $8 – 10 vouchers for the purchase of fresh fruits and vegetables Canned, dried or frozen fruits and vegetables would be allowable substitutes when fresh forms are unavailable.15

pro-Clearly, government guidelines encourage the intake

of all fruits and vegetables, whether fresh, frozen, canned or dried, so long as added ingredients such

as sugar, fat and salt are not significant This recommendation is supported by an independent study at the University of Illinois Department of Food Science and Nutrition Researchers at Illinois compared USDA nutrient data for fresh, frozen and canned fruits and vegetables (Klein BP and Kalitz R, personal communication) They determined that canned fruits and vegetables were nutritionally similar and sometimes superior for some nutrients to their fresh and frozen counterparts.

Although most people do not consume enough total fruits and vegetables, it is interesting to note that

in the USA more processed fruits and vegetables are consumed overall than their fresh counterparts Table 2 details fruits and vegetables commonly

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Table 2 Economic Research Service consumption data (lb per

capita) for 2004 (www.ers.usda.gov/data/foodconsumption/)

Commodity Fresh Frozen Canned

a Total for all processed varieties.

especially important to note changes that may occur

during the processing of tomatoes.16The purpose of

this study is to review the literature on the nutritional

differences between fresh, frozen and canned fruits and

vegetables, concentrating on the years 2000 – 2005.

Results from this review will be presented in two parts.

Part 1 includes the water-soluble vitamins C and B in

addition to phenolic compounds Part 2 will focus on

the lipid-soluble vitamins A and E in addition to other

carotenoids, minerals and fibre 3

Whenever possible, the effects of storage and

cooking on the fresh and processed fruits and

vegetables are also compared Canned foods undergo

thermal processing and are thus most comparable to

cooked fresh or cooked frozen products However,

canned foods can be served cold or reheated For

consistency with previous studies, reheated canned

foods will be referred to as ‘cooked’ Values from

the USDA nutrient database, which are usually

yearly averages owing to seasonal variability, are also

considered.

Vitamin C, the B vitamins and phenolic compounds

are all, to varying degrees, water-soluble, thermally

labile and sensitive to oxidation All these properties

make these nutrients more susceptible to degradation

during processing, storage and cooking than the

nutrients studied in Part 2.

VITAMIN C (ASCORBIC ACID)

Vitamin C is highly water-soluble and sensitive to

heat These properties make it susceptible to

pro-cessing technologies as well as cooking in the home.

According to the Centers for Disease Control and

Prevention, good sources of vitamin C include

broc-coli, tomatoes, leafy greens, apricots and

pineap-ple (http://www.cdc.gov/nccdphp/dnpa/5ADay/index.

htm).

Processing

Canning

Many recent and classical studies have examined the

effects of thermal processing on ascorbic acid for

various commodities (Table 3) Among the recent

Table 3 Ascorbic acid (g kg−1wet weight) in fresh and canned

vegetables

Commodity Fresh Canned

Loss (%) Authors Year Broccoli 1.12 0.18 84 Murcia et al.5 2000 Corn 0.042 0.032 0.25 Dewanto et al.18 2002 Carrots a 0.041 0.005 88 Howard et al.10 1999 Green peas 0.40b 0.096b 73 Weits et al.23 1970 Spinach 0.281 b 0.143 b 62

Green beans 0.163b 0.048b 63

0.053 0.050 NS Jiratanan and 2004

Liu20Beets 0.148 0.132 10

a Average of two consecutive years.

b Based on USDA nutrient database Authors did not provide values.

NS, not significant.

Table 4 USDA nutrient data for ascorbic acid (g kg−1wet weight) in

fresh and canned products 16

Canned Commodity Fresh Drained solids Liquids + solids Green peas 0.40 0.096 0.098 Spinach 0.281 0.143 0.135 Pineapple (juice pack) 0.169 0.094 0.095 Green beans 0.163 0.048 0.034

products studied were tomatoes, asparagus, corn, broccoli, mushrooms and green beans All reported

a decrease in ascorbic acid during commercial thermal processing conditions.5,10,11,13,17 – 23

On a wet weight basis, loss of ascorbic acid during processing ranged from 8% in beets to 90% in carrots.10,20 Martin-Belloso and Llanos-Barriobero13reported their results on a dry weight basis, finding losses of approximately 25 – 30% for white asparagus, lentils and tomatoes and 41% for mushrooms Saccani

et al.22 found similar results for tomatoes They reported ascorbic acid losses ranging from 29 to 33% after normalising tomato samples by bringing concentrations to 5 ◦ Brix Although most studies

did not analyse the drained liquid, any ascorbic acid remaining in the liquid would likely be minimal since it

is easily oxidised This is supported by USDA nutrient data, which show little difference in ascorbic acid content when the canning liquid is included in the analysis along with the fruit or vegetable (Table 4).

Freezing

Several studies considered the effects of freezing on the same product that was canned.5,10,11,21In general, frozen samples contained higher levels of ascorbic acid than canned samples (Table 5) Favell24reported changes in ascorbic acid due to freezing for several vegetables on a dry weight basis He found negligible losses in carrots but 20 and 30% losses in broccoli and green peas respectively.

These results are consistent with older studies

on blanching and freezing, which show the highest

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Table 5 Losses of ascorbic acid (% wet weight) due to canning and

freezing processes

Commodity Canning

Blanching and freezing Authors Year Broccoli 84 50– 55 Murcia et al.5 2000

– 30 Howard et al.10 1999 Carrots 90 0– 35

average losses of vitamin C for spinach and broccoli

and relatively lower amounts for legumes Asparagus is

reportedly most resistant to losses during the blanching

and freezing process, with retention averaging 90%.

Retention of ascorbic acid can vary tremendously in

all products, depending on cultivar and processing

conditions among other variables In general, losses

due to the entire freezing process can range from 10

to 80%, with averages around 50% 1 This compares

favourably with canning, where average losses are

greater than 60%.

Storage

Fresh

In a study on the effects of storage and freezing on

fresh vegetables, Favell24 found that freshly picked

vegetables consistently contained the greatest amounts

of ascorbic acid in all vegetables studied (Table 6).

Ascorbic acid begins to degrade, however, immediately

after harvest Green peas, for example, were found

to lose 51.5% WW of ascorbic acid during the first

24 – 48 h after picking 25 Furthermore, ascorbic acid

degrades steadily during prolonged storage, although

Table 6 Losses of ascorbic acid (% dry weight) due to fresh and

refrigeration can slow its degradation rate (Tables 6 and 7) The losses of ascorbic acid that occur between harvest and consumption suggest that processing can have a preserving effect for some vegetables.10,23,25,26

For instance, levels of ascorbic acid in fresh peas and fresh spinach stored at 4 ◦C fell below levels in the

frozen product after 10 days Fresh storage at ambient temperatures resulted in greater loss; for example, fresh peas stored at ambient temperatures lost 50% of their ascorbic acid in 1 week, while fresh spinach stored

at ambient temperatures lost 100% of its ascorbic acid

in less than 4 days 26

Frozen

Ascorbic acid also continues to degrade during prolonged storage of frozen products (Tables 6 and 7) Losses after 1 year for fruits and vegetables stored at

−18 to −20 ◦C averaged 20 – 50% WW for products

such as broccoli and spinach Asparagus and green peas, which are generally more resistant to processing, suffered minimal losses Hunter and Fletcher 26 did not provide an explanation for the increase observed during storage of frozen green peas, although a change

in moisture content may be responsible Table 6 offers details on specific studies.

Canned

Ascorbic acid losses during storage of canned goods

tend to be small (<15%) when compared with storage

Table 7 Losses of ascorbic acid (% wet weight) due to storage of fresh, frozen and canned vegetables

Fresh Frozen Canned Commodity Time (days) ◦C Loss (%) Time (months) Loss (%) Time (months) Loss (%) Authors Year

Broccolia 21 4 13 12 50 – – Howard et al.10 1999

48 Carrots a 84 5 0 12 NS

10 50 Green beans 16 90 45 – –

– – – 6 4 6 8 Weits et al.23 1970 Green peas – – – NS

21 4 40 1 +20 b – – Hunter and Fletcher26 2002

7 20 60 – – – – Spinach 21 4 75 1 NS – –

4 20 100 – – – – – – – 6 26 6 NS Weits et al.23 1970

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losses in fresh and frozen products (Table 7) At

least two studies have shown that no statistically

significant losses of ascorbic acid occur during storage

of canned green beans at room temperature, and one

study showed a slight loss of 6% after 18 months of

storage of canned green beans.9,27,28 These results

are consistent with classical studies suggesting strong

retention (>85%) of ascorbic acid in canned goods

stored at ambient temperature for up to 1 year 2

Cooking

Depending on the cooking method used, losses of

ascorbic acid during home cooking range from 15 to

55% 29 Additional ascorbic acid losses due to cooking

canned products are minimal, since little if any added

water is needed and the heating time is generally less

than the cooking time needed for fresh or frozen

products.4,25 Unheated canned products are thus

usually compared with cooked fresh and/or cooked

frozen foods Cooked frozen products have often been

shown to be equal or superior to cooked fresh products

in their ascorbic acid levels This is likely due to the

losses of vitamin C during storage of the fresh produce

(Table 8).4,24,26,30

Howard et al.10 compared uncooked and

microwave-cooked fresh refrigerated, frozen and

canned carrots 10 Interestingly, the cooked versions

did not always contain lower amounts of ascorbic

acid Microwave cooking may increase the content of ascorbic acid in a food, although no overall pattern was observed Since results were expressed on a wet weight basis, the apparent increase may be attributed to loss

of soluble solids: the authors suggest that the rate of diffusion of ascorbic acid out of the cell may be slower than that of other solids such as sugars This poses an avenue for future research Of the products compared, cooked canned carrots contained the lowest amounts

of vitamin C, although the results may be nutritionally insignificant, since carrots are not good sources of the vitamin (Table 8).

Retail market products and USDA database

Hunter and Fletcher 26 compared ascorbic acid levels

in fresh, frozen and canned peas and spinach purchased at a retail market (Table 9) 26 Both vegetables contained the lowest levels of ascorbic acid

in the canned form, even after cooking fresh and frozen products Interestingly, fresh was not always best.

Cooked frozen peas and frozen leaf spinach (versus

frozen chopped) contained amounts of ascorbic acid greater than or equal to those in the cooked fresh products These results are inconsistent with USDA data for processed spinach, which report the highest levels of ascorbic acid in the canned form For green peas, USDA data report the highest levels of ascorbic

Table 8 Total losses of ascorbic acid (% wet weight (WW)) due to processing, storage and cooking

Fresh Frozen Canned Commodity

Initial concentration

(g kg −1WW) (days), refrigeratedStorage time Loss(%) Storage time(months) Loss(%) Storage time(months) Loss(%) Authors Year

Broccoli a 1.23 0– 21 5 0– 12 35 – – Howard et al.10 1999

1.80 38 62 Carrots a 0.043 0– 7 42 0– 12 12 0– 12 81

0.039 +50 b 56 95 Green beans 0.152 0– 21 37 0– 12 20 – –

0.163c 0 23 6 48 6 68 Weits et al.23 1970 Green peas 0.40c 0 28 6 66 6 77

0.354 1– 2 61 0 70 0 85 Fellers and Stepat 25 1935 Spinach 0.281c 0 64 6 81 6 67 Weits et al.23 1970

a Authors reported total losses as an average of values collected throughout the total storage time The two values for each vegetable represent results from consecutive years.

b Authors reported an increase.

c Based on USDA nutrient database 16 Authors did not provide values.

Table 9 Average ascorbic acid levels (g kg−1wet weight) found in market-purchased products

Fresh Frozen Canned Commodity Uncooked Cooked Uncooked Cooked Uncooked Cooked Authors Year Green beans 0.057 – 0.020 – 0.212 – Tinklin and Harrison32 1959

0.21 0.13 0.11 0.03 0.04 0.03 Wills et al.33 1984 Green peas 0.32 0.14 0.21 0.11 0.13 0.06

0.183 – 0.194 – 0.0471 – Hunter and Fletcher 26 2002 Spinach 0.289 – 0.35 – 0.029 –

Tomatoes 0.10 0.071 – – 0.107 – Franke et al.6 2004

0.080 – – – 0.080 – Nagarajan and Hotchkiss 31 1999

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Table 10 USDA nutrient data for ascorbic acid (g kg−1wet weight) in selected fruits and vegetables16

Fresh Frozen Canned Commodity Uncooked Cooked Uncooked Cooked Drained solids Liquids + solids Green beans 0.163 0.097 0.129 0.041 0.048 0.034 Green peas 0.400 0.142 0.180 0.099 0.096 0.098 Spinach 0.281 0.098 0.243 0.022 0.143 0.135 Peaches 0.066 – 0.942a – 0.028 0.028 Pineapple (juice pack) 0.169 – 0.080 – 0.094 0.095 Tomatoes 0.127 0.228 – – – 0.090

a Ascorbic acid may be added during processing to prevent enzymatic browning.

acid in cooked fresh peas, with similar levels in cooked

frozen and canned products (Table 10).

In two other retail market studies, purchased fresh

and canned tomatoes were compared.6,31The results

for tomatoes are quite different from those found for

peas and spinach In both studies, canned tomatoes

were found to have similar or higher levels of ascorbic

acid than the fresh product (Table 9) Only one

of these studies cooked the fresh tomatoes, and it

was found that boiling resulted in losses of nearly

30% WW 6 On the other hand, USDA data show

higher levels of ascorbic acid in cooked fresh tomatoes

than in unprocessed tomatoes on a wet weight basis

(Table 10) The discrepancy could be due to variation

in cultivars or cooking techniques.

To further examine the differences in retail market

products, we turned to older studies In one study

conducted for three consecutive years, 1956 – 1958,

researchers compared fresh, frozen and canned green

beans purchased from a market at various times The

beans were cooked ‘with minimum liquid and for

as short a time as feasible to conserve the nutritive

value and the general acceptability of the products’.

These researchers found that cooked fresh green beans

contained, on average, significantly higher levels of

ascorbic acid than cooked canned or frozen beans

(Table 9) In comparing cooked canned and frozen

samples, however, the study found variance due to

grade of bean (A, B or C) and brand of product.

On average, cooked canned green beans contained

comparable amounts of ascorbic acid to cooked frozen

beans 32 A 1984 Australian study found similar results

for market-purchased green beans, with cooked fresh

beans having the greatest amount of ascorbic acid,

while cooked frozen and canned beans contained the

same amount (Table 9) 33

Conclusions

Research supports the common perception that fresh

is often best for optimal vitamin C content, as

long as the fresh product undergoes minimal storage

at either room or refrigerated temperatures While

the canning process causes significant initial loss

of ascorbic acid, further losses due to storage and

cooking are minimal In contrast, the blanching and

frozen products result in significant degradation of the vitamin Studies of produce on the retail market and USDA nutrient data reveal that cooked canned and frozen products can contain similar or higher levels of ascorbic acid as cooked fresh products, depending on commodity Moreover, canned foods such as tomatoes and pineapples can make significant contributions to the RDA for vitamin C More studies with greater sample sizes are needed to compare ascorbic acid levels in foods available to the consumer.

B VITAMINS

The B vitamin family includes thiamin (B 1 ), riboflavin (B 2 ), niacin (B3), biotin, pantothenic acid, B 6 , folate and B12 Their water solubility renders them prone to leaching during cooking and processing Additionally, many of the B vitamins, especially thiamin, are sensitive to degradation during processing Next to vitamin C, thiamin is the least stable of the vitamins

to thermal processing, so its losses are the most studied of the B vitamins.29,34 However, fruits and vegetables are generally not good sources of thiamin,

so its retention may not be representative of the overall nutrient retention of a food.29Riboflavin is unstable to light, so processing and storage conditions play a role

in its retention Since biotin and pantothenic acid are widespread in food, changes in these B vitamins during processing are generally not of nutritional concern B12

is found mostly in animal products, so its sensitivity is not reported here.

Moshfegh et al.35 reported that most Americans consume adequate intakes of riboflavin and niacin Thiamin and folate intakes are lower than desirable among female populations, while inadequate intake of vitamin B 6 was identified as a potential problem for older females Many fruits and vegetables, especially leafy greens, can contribute B vitamins to the diet.

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Canning

Thiamin (B1) Several studies have shown significant

decreases in thiamin content during thermal

process-ing, although the extent of degradation depends on the

commodity.9,13,27Losses may range from 25% DW in

asparagus to 66% DW in spinach.13,36 At least two

recent reports suggest no significant thiamin losses

(WW) after canning tomatoes, although one study

reported a loss of 53% DW.13,22,36 This difference

may be due to the expression of nutrient content on a

dry rather than a wet basis, but the deviation suggests

the need for additional research.

Riboflavin (B2) Retention of riboflavin during the

canning process is much higher than that of thiamin.

Research suggests retention of 68% in mushrooms and

lentils to 95% or higher in asparagus, sweet potatoes

and peaches (DW).9,13Again, there are discrepancies

among tomato studies due to different dry versus wet

weight reporting practices One study of tomatoes

reported a 61% DW retention rate for riboflavin, while

another found no significant decreases during canning

(WW).13,22

Vitamin B6 Retention of B6 during the canning

process ranges from 54% DW in mushrooms to

80% DW in cherries and lentils.13,27 Schroeder 37

found 57 – 77% WW less vitamin B 6 in canned

vegetables than in their fresh counterparts Saccani

et al.22 brought all tomato samples to 5 ◦ Brix before

analysis to account for the change in moisture content.

They found significant increases of 14 – 38% in B 6

after canning tomatoes, depending on the type of can

(lacquered or plain) and the temperature used for

sterilisation.

Niacin (B3) Most data suggest that niacin is stable

to processing 36 Retention rates of 93% or higher

were found after canning and subsequent storage of

green peas, green beans, peaches and sweet potatoes

on both wet and dry weight bases.9,33 In fiddlehead

greens, however, nearly 50% WW of the original niacin

concentration was lost after canning.38

Folate Only one recent study examined folate

reten-tion after canning Jiratanan and Liu 20 found a 30%

WW loss of folate as a result of canning beets but

did not find a reduction in folate after canning green

beans They attributed the results to the reducing

environment in green beans created by packing and

processing in water, whereas the beets were packed

without a filling medium The authors suggested that

the reducing environment created by the addition of

water might allow for the recycling of folate or slow its

degradation.

Freezing

The use of blanching as a pre-freezing treatment is

responsible for the loss of water-soluble B vitamins.

Losses of 9 – 60% thiamin and up to 20% riboflavin have been reported for vegetables such as green peas and beans 39Hebrero et al.40 reported a 30% DW loss

of thiamin in spinach due to blanching before freezing.

Bushway et al.38 found 30, 38 and 35% WW lower levels of thiamin, riboflavin and niacin respectively after blanching and freezing fiddlehead greens.

A few recent studies have compared B vitamins in frozen and canned legumes On a wet weight basis, frozen legumes contained significantly higher levels of thiamin than their canned counterparts.21,33 USDA nutrient data, which report data on a wet weight basis,

support this finding (Table 11) Lisiewska et al.,21

however, found that the differences were insignificant when dry matter content was considered.

Storage

Fresh

Spinach has been found to lose 13 and 46% DW of its original thiamin content during storage for 1 and

3 weeks respectively at 4 – 6 ◦C Green peas retained

much more thiamin, losing only 23% DW after

3 weeks of storage at 4 ◦C Riboflavin also degrades

during storage After 3 weeks at 4 ◦C, losses of 39

and 24% DW were determined for spinach and peas respectively 41 Storage temperature can have a significant effect; even greater losses were found in spinach stored at room temperature 40

Frozen and canned

The few studies on changes in B vitamins during canned and frozen storage suggest that there is some degradation of these vitamins during storage for most products.9,38 During long-term storage (6 – 18 months) at room temperature, significant losses (DW) of thiamin were observed in canned tomatoes and peaches, but only small losses (DW) were found

in canned green beans.9,22,27 Canned tomatoes also lost significant amounts of riboflavin, vitamin B6and niacin during 8 months of storage 22 Canned cherries and green beans lost vitamin B6 during 4 and 6 months of storage respectively 27 For canned and frozen fiddlehead greens, no significant changes

in thiamin, riboflavin and niacin were found during

10 months of storage 38Hebrero et al.40 found a 25.4%

DW increase in thiamin after 40 days in frozen spinach The authors suggest that further research is needed to satisfactorily explain the increase.

Cooking

Cooking vegetables can result in thiamin losses ranging from 11 to 66% WW, depending on the commodity and cooking process 42 Retention of other B vitamins is generally high, although losses due to leaching can be significant, depending on cooking conditions In one study on green peas and green beans, cooked fresh products consistently contained more thiamin and riboflavin than both cooked frozen and canned samples

on a wet weight basis Thiamin, riboflavin and niacin contents were the same in cooked frozen and canned

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green beans In the case of green peas, thiamin and

niacin were significantly lower in the cooked canned

sample than in the cooked frozen sample 33 Since the

results were reported on a wet weight basis, dilution of

the vitamins may account for some of the differences.

Another study showed that cooked fresh and frozen

green peas contained similar amounts of thiamin and

riboflavin on a wet weight basis 41 The frozen product,

however, did not undergo any storage Since these

vitamins may undergo continued degradation during

storage, these results may be nutritionally insignificant.

Other studies suggest that cooked frozen and canned

legumes contain similar amounts of thiamin, although

both contain less than cooked fresh legumes.21,33

USDA nutrient database

USDA nutrient data on selected fruits and vegetables

can be found in Table 11 Canned green beans, green

peas and spinach generally contain the least amount of

B vitamins when compared with their fresh and frozen

counterparts Canned peaches are similar to frozen

peaches in B vitamin content, although both contain

lower amounts than fresh peaches Canned tomatoes

generally contain higher levels of B vitamins than fresh

tomatoes.

Conclusions

Although there are inconsistencies with methodology

and data reporting, most data suggest that the B

vitamins are sensitive to thermal processing, storage

and cooking However, more studies should be

completed to determine the differences in fresh, frozen

and canned products available to the consumer at

retail markets Most importantly, dry weight results

should be reported to avoid apparent differences due

to changes in moisture content during processing and

storage.

PHENOLIC COMPOUNDS

Epidemiological studies show positive correlations

between a diet high in phenolic-rich fruits and

vegetables and reduced risk of chronic diseases such

as cancer and cardiovascular disease In general, phenolic compounds are thus considered a positive quality of fruits and vegetables 43 However, phenolic compounds are not considered vital nutrients for humans, and their potential benefit to human health is still under discussion Their nutritional benefits are often attributed to their substantial antioxidant activity Some researchers have suggested that phenolic compounds are responsible for stalling

or stopping the ‘initial trigger’ of chronic disease by serving as sacrificial antioxidants to damaging oxidants

in the body.43,44 Since there are hundreds of phenolic compounds found in fruits and vegetables, many authors report composite total phenolic (TP) values.

Processing

The phenolic composition of fruits and vegetables is dependent on commodity, cultivar, maturity stage and postharvest conditions Since phenolic compounds are antioxidants, they are subject to oxidation during storage and processing of foods.44 The blanching process often used prior to canning and freezing inactivates enzymes that cause the oxidation of phenolics 45 However, chemical degradation can still occur during storage, depending on available oxygen and exposure to light.

Phenolic compounds are also water-soluble, dering them susceptible to leaching Furthermore, phenolic compounds and other phytochemicals are found in significant amounts in the peels of fruits, so some content is lost during the peeling step of processing Removal of peach peel resulted in 13 – 48% loss

ren-of total phenolics, depending on the maturity stage ren-of the fruit 46 Separation of other plant tissues, such as removal of mushroom stems, may also influence the final phenolic composition of a food.

Canning

Several researchers have reported significant declines

in TP content due to thermal processing The

Table 11 USDA data for B vitamins (g kg−1wet weight) in selected fruits and vegetables16

Commodity Thiamin Riboflavin Niacin B6 Folate Green beans Cooked from fresh 0.00074 0.00097 0.00614 0.00056 0.00033

Cooked from frozen 0.00035 0.00090 0.00383 0.00060 0.00023 Canned 0.00015 0.00056 0.00201 0.00037 0.00032 Green peas Cooked from fresh 0.00259 0.00149 0.0202 0.00216 0.00063

Cooked from frozen 0.00283 0.00100 0.0148 0.00113 0.00059 Canned 0.00121 0.00078 0.00732 0.00064 0.00044 Tomatoes Cooked from fresh 0.00036 0.00022 0.00532 0.00079 0.00013

Canned 0.00045 0.00047 0.00735 0.00090 0.00008 Peaches Cooked from fresh 0.00024 0.00031 0.00806 0.00025 0.00004

Cooked from frozen 0.00013 0.00035 0.00653 0.00018 0.00003 Canneda 0.00012 0.00026 0.00614 0.00019 0.00003 Spinach Cooked from fresh 0.00095 0.00236 0.00490 0.00242 0.00146

Cooked from frozen 0.00078 0.00176 0.00439 0.00136 0.00121

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evidence suggests, however, that the decline is largely

due to leaching into the brine or syrup rather

than oxidation.47,48 Furthermore, vegetables vacuum

packed and/or canned without a liquid topping juice

(beets, tomatoes and corn) were found to have very

slight changes in their TP content (Table 12) In fact,

beets experienced a further increase ( +17% WW from

control) after additional heating for a total of 45 min 20

Interestingly, Bing cherries also experienced an overall

increase in TPs due to thermal processing when the

canning syrup was included in the analysis However,

50% WW of the TPs were transferred from the fruit

to the syrup 47

The largest loss of TPs due to canning was found

in mushrooms (Table 12), which underwent several

washing and immersion steps in addition to thermal

processing.49 The stems of the mushrooms were also

removed, but the authors did not quantify the TPs

that may have been lost in this step This may be

important, since other authors have suggested stem

removal as a significant reason for nutrient loss in

mushrooms 13 Two brines were used in canning to

determine the effects of adding ascorbic acid to the

canning medium As expected, mushrooms canned

with ascorbic acid had a retention rate 20% WW higher

than those canned without ascorbic acid, suggesting

that oxidation is also a significant cause of loss of TPs

in mushrooms.

When analysing specific phenolic compounds,

similar results were found Total flavonoids decreased

by 60% WW in green beans packed in water but

increased by 30 – 50% WW in beets in which no topping juice was used 20 No significant change was found in total flavonoids after canning tomatoes 8

Anthocyanins were found to increase slightly in Bing cherries after canning with syrup, but nearly 50% WW of the anthocyanins were transferred to the syrup 47 Although procyanidin values for fresh

clingstone peaches were not reported, Hong et al.48

compared frozen peaches with canned peaches and reported that the apparent losses observed during thermal processing may be attributed to migration

of procyanidins into the canning syrup.

Freezing

In general, freezing causes minimal destruction

of phenolic compounds in fruits, with retention levels dependent on cultivar 49 – 51 Increases in the phenolic content of some fruit varieties have also been reported (Table 13) After freezing raspberries,

Gonz´alez et al.50 found a 12% WW loss in one early harvest cultivar but a 12% WW gain in another The authors also found increases (up to 40% WW)

in total anthocyanins for early harvest cultivars but decreases ( −17% WW) for late harvest varieties The late harvest raspberries, however, still contained significantly higher levels of total anthocyanins after freezing The same study found 8 and 15% WW losses of TPs and total anthocyanins respectively after freezing wild blackberries In another study

on raspberries, no significant difference in total anthocyanins and TPs was found after freezing 51

Table 12 Total phenolics (g gallic acid equivalents kg−1wet weight (WW)) in fresh and canned products

Commodity

Fresh product

Canned product (drained)

Total canned product (fruit or vegetable + canning liquid)

Change due to canning (% WW) Authors Year Beets 1.20 1.30 No liquid used +5 Jiratanan and Liu20 2004 Green beans 0.78 0.53 Not reported −32

Bing cherries 1.94 1.13a 233 −40 b Chaovanalikit and Wrolstad47 2004

1.17 a 259 Clingstone peaches 0.397 0.314 Not reported −21 Asami et al.46 2002 Corn 0.72 0.68 No liquid used −5 Dewanto et al.18 2002 Tomatoes 0.142 – 0.149 NS

Mushrooms 1.80 0.162 Not reported −91 Vivar-Quintana et al.49 1999

0.603 c −67 c

a Results for canned product correspond to different batches.

b Does not include syrup.

c Ascorbic acid was added to canning brine.

Table 13 Total phenolics (g gallic acid equivalents kg−1wet weight) in selected fresh and frozen fruits

Commodity Fresh Frozen % change Authors Year Raspberries 0.576 0.565 NS Mullen et al.51 2002

1.134– 1.782 0.996– 1.885 −12to +12 a Gonz ´alez et al.50 2003 Blackberries 9.7771 9.036 −8

Peaches (peeled) 0.326 0.423 +30 Asami et al.46 2003

a Results varied by cultivar.

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Asami et al.46 found a significant (30% WW) increase

in the TPs of clingstone peaches after freezing.

Puupponen-Pimi¨a et al.52 studied the effects of

blanching and freezing on phenolic compounds of

peas, carrots, cauliflower, cabbage and potatoes The

authors reported an average loss of 20 – 30% DW

of TPs in most vegetables, although no change was

observed in most carrot samples and a 26% DW

increase was observed in cabbage.

Storage

Fresh

Mullen et al.51 simulated the storage of fresh

raspber-ries to predict levels in fruits available at retail market

(3 days of storage) and at home (additional 24 h).

The levels of TPs increased slightly but significantly

during the 3 days of storage and the additional 24 h

period The authors suggest that continued secondary

metabolic activity in the stored fruits is responsible for

the increases observed in TPs No significant change

was found in total anthocyanin content.

Asami et al.46 reported no significant loss of TPs

during cold storage of peeled and unpeeled peaches.

Interestingly, they found significant gains (69 and

36% WW respectively for peeled and unpeeled fruits)

during 24 h of storage at 30 ◦C Levels began to drop

off after 24 h, although at 48 h the peeled and unpeeled

fruits still contained 50 and 28% WW more TPs

respectively than fresh fruits The authors attributed

these gains to the possibility of increased activity

of enzymes involved in phenolic synthesis, due to

elevated temperatures and tissue stress induced by

peeling.

Vegetables may not experience the same beneficial increase reported during fresh storage of fruits Vallejo

et al.53 stored freshly harvested broccoli for 7 days

to simulate maximum time spent in transport and distribution and for a further 3 days to simulate time spent in a retail market After the 10 days, large amounts of phenolic compounds were lost The authors reported losses of 44 – 51, 59 – 62 and 73 – 74%

WW for sinapic acid derivatives, total flavonoids and caffeoyl-quinic acid derivatives.

Frozen

Changes in TPs during frozen storage seem to depend heavily on commodity No statistically significant change was observed in TPs of frozen peaches during 3 months of storage on a wet weight basis 46

Puupponen-Pimi¨a et al.,52 however, found some losses

of TPs on a dry weight basis during 12 months of frozen storage of broccoli, carrots, cauliflower, peas and potatoes (Table 14) Significant decreases in TPs and total anthocyanins were also found during frozen storage of Bing cherries (Table 15) Losses of 50 and 87% WW of TPs and total anthocyanins respectively were recorded after 6 months of storage at −20 ◦C.

Cherries stored for 6 months at −70 ◦C, however,

retained 88% of total anthocyanins and 100% of TPs 47

Changes in TPs are also dependent on cultivar.

Gonz´alez et al.50 studied four raspberry cultivars and found different results for each, ranging from no change to an increase of 12% and decreases of

21 and 28%, during 12 months of frozen storage Since retention of phenolic compounds seems to be quite erratic during frozen storage, further research

Table 14 Changes in total phenolics (g gallic acid equivalents kg−1dry weight) during freezing and 12 months of frozen storage of vegetables52

Commodity Fresh Initial frozen

% change due to freezing Final frozen

% change during frozen storage Broccoli – 3.20 NA 3.10 −3 Cabbage 1.90 2.40 +26 1.90 −21 Carrots 1.10– 1.30 0.80– 1.30 0 to −33 0.80– 1.20 −17 to +20 Cauliflower 5.60 4.90 −13 4.50 −8 Peas 0.80– 1.20 0.60– 0.90 −13 to −25 0.60– 0.90 0 to −14 Potatoes 0.50– 0.60 0.30– 0.60 −16 to −40 0.40– 0.50 −20 to +67

NA, not applicable.

Table 15 Total phenolics (g gallic acid equivalents kg−1wet weight) in fresh, frozen and canned fruits after storage

Commodity

Original

content

Storage time (days)

Fresh stored (4 ◦C)

Storage temp.

( ◦C)

Storage time (months)

Frozen stored

Storage temp.

( ◦C)

Storage time (months)

Canned, drained

Canned, including syrup Authors Year Bing 1.94 – – −23 3 1.45 2 5 1.27 2.35 Chaovanalikit 2004 cherries 6 0.96 and Wrolstad47

−70 3 2.10 22 5 1.21 2.31

6 2.00 Peeled 0.398 7 38.5 −12 3 0.50 Ambient 3 0.221 – Asami et al.46 2003 peaches 14 37.8 6 0.247 –

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should be completed to specify other variables, such

as packaging, that may influence retention rates.

Canned

Peaches canned in enamel-coated cans lost 30 – 43%

WW of TPs after 3 months of storage at room

temperature (Table 15).46The authors did not assay

the syrup in this study, but in a subsequent study they

reported that the procyanidins lost during canning had

actually migrated to the syrup.48 Chaovanalikit and

Wrolstad47 found similar results for cherries canned

in enamel-coated cans (Table 15) Significant losses

of anthocyanins were found in canned cherries and

their syrup stored for 5 months at room temperature.

Slight but insignificant decreases in TPs, however,

were found after 5 months of storage at both chilled

and room temperatures The level of TPs in the

cherries and syrup was still higher than that in fresh

cherries, however, owing to the apparent increases

during thermal processing.

Some authors have suggested that the degradation

of phenolic compounds during canned storage may be

dependent on the type of can used Tin-plated cans

can sacrifice tin to compete for available oxygen, thus

sparing some of the phenolic compounds.46Research

is needed to determine if this is a viable method

for increasing retention rates of phenolic compounds

during canned storage.

Cooking

Changes in TPs of vegetables during cooking depend

on commodity, cooking method and cooking time.

Dewanto et al.8 found that the gains of TPs and

flavonoids during thermal processing of tomatoes were

not significant on a wet weight basis.8Gahler et al.,19

however, found up to a 44% gain of TPs during the

baking of tomatoes and up to a 64% increase in TPs

during the cooking of tomato sauce on a wet weight

basis Franke et al.6 found that retail-purchased fresh

tomatoes lost 30 – 60% WW quercetin upon boiling.

Turkmen et al.54 studied the effects of cooking

(boiling, steaming and microwaving) on TPs in the

dry matter of fresh purchased pepper, squash, green

beans, leeks, peas, broccoli and spinach Some losses of

up to 40% DW were found after cooking squash, peas

and leeks, although pepper, green beans and spinach

experienced increases in TPs during all cooking

methods Broccoli increased in TP content by 16%

DW after steaming or microwaving but lost a slight

(6% DW) amount of TPs from boiling.

These results differ from those of Zhang and

Hamauzu, 55 who found that broccoli lost up to 70%

WW of its TPs after boiling or microwaving This

difference could be due to the change in moisture

content of the broccoli during cooking, since Zhang

and Hamauzu reported their results on a wet weight

basis.

Clearly, more research is needed to determine

the effects of cooking on total phenolics as well as

individual phenolic compounds Research is especially

needed to determine any further changes in the phenolic make-up of frozen and canned products during cooking.

Retail market products

Since phenolic compounds can undergo oxidation during storage and transport to the retail market, it

is important to measure the phenolic composition

of market-available food products As mentioned previously, several authors have simulated these conditions as fresh, frozen and/or canned storage

of single cultivars Several other researchers opted

to purchase fresh tomatoes and canned tomato products to quantify what is available to the consumer Nagarajan and Hotchkiss 31 found significantly higher levels of TPs in canned tomato products compared with fresh tomatoes on a wet weight basis When they adjusted their results for the same amount

of total soluble solids, however, they found similar levels in most products Tomato paste and juice were exceptions, with canned tomato paste containing about 40% less TPs and canned tomato juice containing about 67% more TPs than fresh tomatoes.

Franke et al.6 measured individual flavonoids and total flavonoids in canned, fresh and boiled fresh tomatoes Total flavonoids were highest in fresh tomatoes purchased at a market; boiled and canned tomatoes contained similar amounts of flavonoids.

On average, canned tomatoes contained 44% WW less quercetin than fresh tomatoes 6 Finally, Podsedek

et al.56 measured the polyphenol content in bottled tomato juices and canned tomatoes but not in fresh tomatoes They found that the content in their purchased products was similar to the values reported for fresh tomatoes by other authors.

The phenolic composition of other fruits and vegetables and their processed products available to the consumer should be studied in the future Since different cultivars are used for fresh, frozen and canned products, the phenolic make-up of retail goods is likely

to vary significantly within individual commodities.

Conclusions

Changes in phenolic compounds during processing, storage and cooking appear to be quite variable and may depend highly on commodity Future studies may clarify some of the reported discrepancies Thermal treatment via cooking, blanching or canning appears

to increase the extractability of phenolic compounds However, since phenolic compounds are both water- soluble and sensitive to oxidation, degradation of TPs

is possible during fresh and frozen storage Decreases

in stored canned foods may be due to migration of TPs from the fruit or vegetable to the canning medium; however, further research is necessary Currently, the USDA does not include TP values in the nutrient database Since the reported data are rather erratic, future evaluation of TP contents of retail market foods may be germane A standardised method of analysis

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and reporting (wet or dry weight) is also essential for

comparing study results.

IMPLICATIONS

Losses of nutrients during fresh storage may be more

substantial than consumers realise Depending on

the commodity, freezing and canning processes may

preserve nutrient value While the initial thermal

treatment of canned products can result in loss,

nutrients are relatively stable during subsequent

storage owing to the lack of oxygen Frozen products

lose fewer nutrients initially because of the short

heating time in blanching, but they lose more nutrients

during storage owing to oxidation In addition to

quality degradation, fresh fruits and vegetables usually

lose nutrients more rapidly than canned or frozen

products Other variables such as storage and cooking

conditions will also influence the final nutrient content

of a food Consumers should consider such variability

when utilising nutrient guidelines such as the USDA

nutrient database.

Updates to nutritional recommendations for

humans of all ages are ongoing Exclusive

recom-mendations of fresh produce ignore the nutritional

value of canned and frozen products and may conceal

the sensitivity of fresh products to nutrient loss Since

nutrient retention is highly variable, a diet filled with

diverse fruits and vegetables is ideal The results

pre-sented here suggest that canned, frozen and fresh fruits

and vegetables should all continue to be included in

dietary guidelines The Global Fruit and Vegetables

Initiative for Health should consider the benefits of

including all forms of fruits and vegetables in their

recommendations There are, however, limitations to

the present work Some of the nutrient losses reported

during processing, storage and/or cooking may be

sta-tistically significant but not significant in terms of

human nutrition For instance, carrots lose significant

amounts of vitamin C during canning, but they are not

good sources of this nutrient to begin with Similarly,

other products such as pineapple contain high enough

levels of vitamin C that they remain good sources of

the nutrient despite degradation during thermal

pro-cessing Our research also did not examine the effects

of other ingredients, such as added sugar, that may

affect the overall nutritional value of processed fruits

and vegetables This may be particularly important for

canned fruits, which are often filled with syrup While

draining the syrup may minimise sugar intake, it may

also result in nutrient loss: our research suggests some

nutrients may migrate into the syrup or canning

liq-uid Vacuum-packed fruits and vegetables appeared to

experience less degradation of phenolic compounds;

however, further research is also necessary to

deter-mine the significance of these results.

Nutrition labels do not impart the significant

degradation of nutrients that may occur during

storage of canned goods owing to the lack of oxygen, nutritional labels are valuable sources of information for these products Nutritionists thus must interpret our results carefully Fresh cut vegetables were not examined in this study owing to the lack of research However, we might assume that these products would experience more rapid degradation of oxygen-sensitive nutrients during storage compared with their intact fresh counterparts owing to the increased exposure to oxygen.

GENERAL CONCLUSIONS

While canned foods are often regarded as less nutritious than fresh or frozen products, research reveals that this is not always true The effects of processing, storage and cooking are highly variable by commodity In general, while canning often lowers the content of these water-soluble and thermally labile nutrients, storage and cooking of fresh and frozen vegetables can also significantly lower the nutritional content Unfortunately, very few studies followed the same product from harvest through processing, storage and cooking Since nutrient and phytochemical content is highly dependent on commodity, cultivar and growing practices, more studies following the same food throughout the consumer chain would be beneficial Analysis of fresh, frozen and canned fruits and vegetables available in retail markets would also

be more appropriate for understanding the nutritional content of fruits and vegetables available to the consumer Additionally, these retail market studies would be a useful supplement to the USDA nutrient database.

Understanding nutrient data is quite complex Variance in methodologies and practices makes interpretation of data difficult Changes in moisture content during storage, cooking and processing often misrepresent changes in nutrient content Future research should focus on nutrient data expression

on a dry weight basis to account for such changes Furthermore, many current reports in the literature refer to nutrient retentions for processing, storage and cooking that were compiled more than 25 years ago.

It is necessary to update these data, standardising process and reporting methods.

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Evaluation of the Quality of Canned Seafood with Added Spice-oil Extract

Ho Dong Yoon 1 , Yu P Shulgin 2 , L Yu Lazhentseva 3 , L V Shulgina 2 , Chengliang Xie 4 , Jong Soo Mok 1 and Jeong Gyun Kim 4 *

1 Southeast Sea Fisheries Research Institute, National Fisheries Research and Development Institute, Tongyeong 650-943, Korea

2 Medical Sciences, Far Eastern Federal University (FEFU), 8, Suhanova St., Vladivostok, 690950, Russia

3 Pacific Scientific Research Fisheries Tinro Centre, 4, Shevchenko Alley, Vladivostok, 590091, Russia

4 Department of Food Science & Technology/Institute of Agriculture and Life Science, Gyeongsang National University,

Jinju 660-701, Korea

Abstract

The influence of spice (cinnamon, allspice, black pepper)-oil extract on canned seafood quality was studied During the cessing of canned seafood, the substitution of spice-oil extract for vegetable oil (refined sunflower, corn, soybean and olive oil) resulted in a decrease in the heat resistance of spore microorganisms, making it possible to reduce the duration of sterilization for canned food to 5-10 min at 115 ° C This reduction in the sterilization duration of canned seafood with spice-oil extract inhibited residual microflora in the product, thus reducing the deleterious effect of heating on the main food compounds while preserving

pro-protein digestibility

Key words: Spice-oil extract, Canned foods, Heat resistance, Sterilization, Digestibility, Fatty acids

Introduction

Microbiological safety is a fundamental property to be

considered in the creation and development of technology for

food processing and preservation Some techniques used to

ensure microbiological safety, including the addition of

pre-servatives, increases in acidity, and high-temperature

process-ing, result in the destruction, inactivation or growth

stabiliza-tion of microorganisms However, such measures often lead to

reductions in food quality.

For food preservation, canning, a technology that relies on

high-temperature processing or sterilization, provides a

reli-able means of securing microbiological safety In most

coun-tries, including Russia, the sterilization of fish and non-fish

food products is conducted to kill spoiling and pathogenic

organisms (Giprorybflot, 1996; Shul'gina, 1995) As a

qual-ity test organism, highly heat-resistant spores of Clostridium sporogenes-25 (C sporogenes-25) are targeted.

Although the sterilization process secures microbiological safety, it results in the loss of native properties of products and has some undesirable effects, including the accumulation

of products of nutrient destruction, the formation of lecular-weight nitrogen compounds, and reductions in food digestibility and assimilation (Shvydkaya and Blinov, 2008; Shulgin, 2006; Shulgin et al., 2006) A well-known method

high-mo-of reducing the heat resistance high-mo-of spore microorganisms in canned seafood and decreasing the requisite rigidity of sterilization modes is through the creation of an acidic environment

in the canned product (Mazokhina-Porshnyakova et al., 1977), which is barely acceptable for fish and non-fish goods canned

Received 29 October 2014; Revised 16 December 2014 Accepted 22 December 2014

*Corresponding Author

E-mail: kimjeonggyun@nate.com

Original Article

Fish Aquat Sci 18(1), 7-11, 2015

This is an Open Access article distributed under the terms of the Creative

Commons Attribution Non-Commercial Licens (http://creativecommons.

org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use,

distribution, and reproduction in any medium, provided the original work

is properly cited.

http://e-fas.org

Trang 36

Fish Aquat Sci 18(1), 7-11, 2015

in the product was determined by the capillary method

(Flau-menbaum, 1986) C sporogenes-25 spores were

character-ized by their heat resistance in a phosphate-buffered solution

D121°C = 0.58 min The reliability of pre-developed sterilization modes was assessed under laboratory conditions by artificially infecting canned seafood in which the vegetable oil was com-

pletely replaced by spice-oil extract C sporogenes-25 spores

(n=38,000) were introduced into the center of the contents of

30 110-g-net-weight glass jars of canned seafood The

infect-ed canninfect-ed goods in glass jars were sterilizinfect-ed in water at ter pressure (0.18 MPa) and then cooled by water at counter pressure

coun-The constant of the spore heat resistance Dt, where t is a constant temperature, at which 90% of cells die during time interval D, was calculated graphically The experiment was repeated three times for each extract The arithmetic mean of the results from three experiments was used The value of the normative sterilizing effect (Fn in conditional min) was calculated using formula (1):

F n = D121°C *(lgB/b + x) (1)

where D 121°C is the heating time in min required to reduce

the amount of Cl sporogenes-25 spores by a factor of 10;

B is the initial number of microbial spores in one gram of product before heating at 121.1 ° C; b is the finite amount

number of microbial spores surviving after heating; lg B/b is

the logarithm of the surviving spores, taken with the site sign; and x is a correction to take into account deviation

oppo-in the number of survivoppo-ing cells after the heatoppo-ing of spores from the log scale of death The thermo-physical characteristics of the canned food content and the factual sterilizing effect (F f ) were assessed using STF-9004 (manufactured by ELLAB, Denmark) The calculation of de facto lethality in sterilization modes was performed according to the manual

of Flaumenbaum (1986) The factual lethality (F f ) of the ilization mode is the stationary equivalent of the concrete non-stationary mode, expressed in conventional 121.1-degree min, which allows for the quantification of the microbiological efficiency of any sterilization mode The value of

ster-Ff was calculated using formula (2):

F f = Ι p * [K f1 + K f2 + + K fn] (2)

where F f, is the time interval between temperature

measure-ments in the can center and K f is the value of the conversion coefficient at the moment of measurement.

Digestibility

The factual digestibility of canned seafood was determined using the biotesting method recommended by Shulgin et al

in oil This method allows for effective sterilization without an

excessive thermal load on canned food, thus guaranteeing the

commercial sterility of food products The aim of this work

was to investigate the influence of spice-oil extract on the heat

resistance of microorganisms in canned seafood, the modes of

product sterilization, and the quality of the product.

Materials and Methods

Preparation of canned food

The preparation of semi-finished canned seafood products

was carried out in accordance with “The technological

in-structions for preparing canned seafood from non-fish

ob-jects” (Giprorybflot, 1989) The following ingredients were

used in canning: frozen sea cucumber, frozen octopus,

fro-zen surf clam, frofro-zen squid, frofro-zen whelk, frofro-zen sea scallop,

frozen mussels, refined sunflower, corn, soybean and olive

oils, edible salt, powdered black pepper, powdered allspice

and milled cinnamon Spice-oil extract was prepared as

fol-lows; milled spices (cinnamon, allspice, black pepper) and

vegetable oils were mixed, heated and incubated at 80 ° C

for 24-36 h The mixture was cooled and the sediment and

spice-oil were separated (Lazhentseva et al., 2011) The cut

and washed seafood meat was placed on grids in a smoking

room The flue-curing mode was employed for 20 min at

23-25 ° C, until the seafood attained the mellow flavor and light

aroma of smoked seafood meat The prepared seafood was

batched by size and packed in 90-g glass jars Twenty cubic

centimeters of spice-oil extract or vegetable oil were poured

into the experimental and control jars of canned seafood,

re-spectively The spice-oil extract was a clear flavored oil with

a brownish tinge and pleasant cinnamon smell, from which

microorganisms were absent (Lazhentseva, 2011) After

fill-ing, the jars were rolled using a vacuum, and the patterns

of their heating during the sterilization process in water at a

counter pressure of 0.18MPa at 115 ° C in an AV-2 autoclave

were investigated To compare canned food quality, five

ex-perimental cans of each product and five control cans of

sea-food with added vegetable oil were sterilized.

Sterilization mode

The canned seafoods, namely, smoked mixed seafood in

oil, smoked sea cucumber in oil and smoked surf clams in oil,

were produced according to recommendations for developing

the sterilization modes of canned fish and fish products

(Gipro-rybflot, 1996; Agribusiness, 2004; Flaumenbaum, 1986)

A suspension of spores of C sporogenes-25, a known

spe-cific spoiling pathogen of canned seafood, was obtained from

the Laboratory of Microbiology, Giprorybflot Institute,

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Rus-Yoon et al (2015) Evaluation of the Quality of Canned Seafood Added with Spice-oil Extracts

previous findings on the effects of spice extract on spores (Lazhentseva, 2011).

Similarly, the calculated values of normative F n for the experimental canned seafood were lower than those of the control product The obtained data were used to determine the duration of sterilization of canned food, which provides

the required values of the factual sterilizing effect (F f) Efficient heating time was determined by taking into account the heating of control and experimental canned seafood during sterilization at 115 ° C The durations necessary for the effective sterilization of experimental samples were 5 min (smoked surf clam and smoked mixed seafood in oil) to

10 min (e.g smoked sea cucumber in oil) shorter than those

of the control samples (Table 2).

All canned goods were industrially sterile after tion The addition of spice-oil extract to canned goods result-

steriliza-ed in an attractive appearance and a weak aroma of spices The replacement of vegetable oil with spice-oil extract can

be assessed as effective for its observed ability to decrease the necessary sterilization duration by 5 to 10 min, inflicting thermal damage on microbial contaminants while preserving proteins and biologically valuable nutrients (Brazhnikov, 1987; Gelfand, 1994; Mazokhina-Porshnyakova et al., 1977).

Fatty acid analysis

The total lipids in a sample were extracted with chloroform/

methanol according to the method of Bligh and Dyer (1959)

Total lipids were separated into phospholipids and

non-phospholipids using silica cartridges (Alltech, silica, 1.5 mL,

100 mg) according to the method of Juaneda and Rocouelin

(1985) The fatty acid content was expressed as a percentage

of individual FAME in relation to the total area of the

chro-matogram (AOAC, 1995)

Results and Discussion

First, the constant of heat resistance, D121.1 ° C , was

deter-mined This value was then used to calculate the normative

sterilizing effects for canned seafood Indicators of heat

re-sistance and the calculated values of the normative sterilizing

effects for canned seafood with the addition of vegetable oil

and spice-oil extract are presented in Table 1 The lethal time

for spores of the test strain, C sporogenes-25 in all types

of canned seafood with added spice-oil extract was lower

than that of those canned with vegetable oil, which parallels

Table 1. Comparative values of the indicators D 121.1 °C , F n for canned seafood.

Title of canned seafood D 121.1 °C, min F n , continued min

Control Experimental Control Experimental

Table 2. Duration of sterilization and factual sterilizing effect for the control and experimental canned seafood

Type of canned seafood

Canned seafood with addition Vegetable oil Spice-oil extracts

F n , cond min Sterilization time F f, cond min F n , cond min Sterilization time F f, cond min

1 Come up time – Processing time – Cooling time.

Table 3. Influence of oil component on the number of cells Bacillus subtilis in canned seafood in oil

Title of canned seafood

Number of cells Bacillus subtilis in 1 g of product content

Before sterilization After sterilization

Control Experimental

Trang 38

Fish Aquat Sci 18(1), 7-11, 2015

facultative anaerobic microorganisms in the experimental samples were equal to 0, meaning that they were industri-

ally sterile Viable cells of B subtilis remained in the control samples at lower counts after sterilization, but B subtilis was

not detected in the spice-oil extract samples (Table 3) One of the indicators of the degree of the preservation of nutritional value during the sterilization process is the thermal damage of proteins, which affects their digestibility To assess the effects of spice-oil extract and sterilization modes

on the digestibility of proteins, biotesting was carried out Fig 1 presents the protein digestibility of the experimental and control samples of canned seafood before and after sterilization The replacement of vegetable oil by spice-oil extract was accompanied by an increase in accessibility of the canned seafood protein component, with a 10.1% increase

in smoked surf clams, an 8.5% increase in smoked mixed seafood and an 8.6% increase in smoked sea cucumber It

is possible that the minor fat-soluble components of spices have a direct positive effect on the digestibility of the proteins contained in seafood canned with spice-oil extract Fatty acids are destroyed during thermal processing (Brazhnikov, 1987; Gelfand, 1994) The influence of spice- oil extract on the persistence of the lipid component in canned seafood was estimated by comparing the fatty acid compositions of control and experimental samples of the sterilized products The oil fraction of canned seafood, which had been stored for 30 days after manufacture, was used to evaluate fatty acid composition.

The fatty acid compositions of canned seafood with ous vegetable oils or with their mixture (control) and with spice-oil extract (experimental) are summarized in Table 4 The results indicated differences in the fatty acid contents of oils from the control and experimental samples The

vari-Dutova et al (1976), Mazokhina-Porshnyakova et al

(1977) and Syromyatnikova (1964) noted that parts of the

spore-forming cells of Bacillus subtilis (B subtilis) in canned

seafood survived sterilization and remained viable

through-out the term of storage The presence of bacilli, even in their

resting state, affects the quality of canned food and leads to

the “aging” of protein products According to the rules and

norms of sanitization, B subtilis are permitted as “residual”

microflora in sterilized canned seafood, but their abundance

therein must not exceed 11 cells per 1 gram of product Thus,

the number of B subtilis cells in the canned seafood with

spice-oil extract was determined before and after

steriliza-tion Table 3 shows that, before sterilization, the total number

of bacilli averaged 320 ± 64 cells per 1 g of product, while

after sterilization, the numbers of mesophilic aerobic and

Fig 1. Digestibility of the protein component contained in the control

(vegetable oil) and experimental (spice-oil extracts) samples.

Table 4 Comparative characteristics of fatty acid composition in canned seafood

Mixture of soybean and sunflower oils (60:40) 21.2 ± 0.1 24.5 ± 0.2 54.3 ± 0.2 17.6 ± 0.3 23.4 ± 0.1 59.0 ± 0.2

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Yoon et al (2015) Evaluation of the Quality of Canned Seafood Added with Spice-oil Extracts

Bligh EG and Dyer WJ 1959 A rapid method of total lipid extraction and purification Can J Biochem Physiol, 37, 911-917.

Brazhnikov AM 1987 Theory of thermal processing of meat products Agropromizdat, Moscow, 1-270.

Agribusiness 2004 No 9273-001-50834905-04: Canned seafood, Agribusiness-Slavic 2000, Vladivostok, Russia, 1-17

Dutova EN, Goftarsh MM, Prizrenova II and Sazonova AS 1976 Technical microbiology of fish products Food Industry, Moscow, 1-272

Flaumenbaum BL 1986 Basics of food preservation Agropromizdat, Moscow, 1-494

Gelfand SY 1994 Scientific Basis of Regulation of Quality and Control

of Canned Goods: abstract of doctoral dissertation, Russian emy of Agricultural Sciences, Moscow, 1-70.

Acad-Giprorybflot 1989 Collection of technological instructions for the duction of canned fish and preserves: Part 4, Giprorybflo, St Pe- tersburg, Russia, 144-156.

pro-Giprorybflot 1996 Instruction on developing the sterilization modes of canned fish and fish product.

Giprorybflo, St Petersburg, Russia, 1- 42.

Juaneda P and Rocouelin G 1985 Rapid and convenient separation of phospholipids and non phosphorus lipid from rat heart using silica cartridges Lipids 20, 40-41.

Lazhentseva LY 2011 Influence of the cinnamon oil extract on spore heat resistance of microorganisms: spoiling pathogens of canned food Scientific works of Dalrybvtuz, Vladivostok, 24, 146-151 Lazhentseva LY, Kim EN, Shul’gina LV and Shul’gin RY 2011 Meth-

od of obtaining of oil for food Patent RU 2427277 Bull No 24, 1-7.

Mazokhina-Porshnyakova NN, Naydenova LP, Nikolaeva SA and zanova LI 1977 Analysis and evaluation of quality of the canned food by microbiological indicators Food industry, Moscow, 1-471 Shulgin YP 2006 Hygienic substantiation of strategy and tactics of im- proving the quality and safety of seafood in nutrition of healthy and sick people: abstract of doctoral dissertation, St Petersburg State Medical Academy, II Mechnikov Federal Agency for Health and Social Development, St Petersburg, 1-40

Ro-Shulgina LV 1995 Scientific substantiation of lethality of the tion processes of canned marine hydrobionts: abstract of doctoral dissertation, Mendeleev University of Chem Tech of Russia, 1- 42 Shulgin YP, Shulgina LV and Petrov VA 2006 Accelerated biotic evaluation of the quality and safety of raw materials and products from aquatic biological resources Pacific State University of Econom- ics, Vladivostok, 1-131

steriliza-Shvydkaya ZP and Blinov YG 2008 Chemical and Biotechnological Aspects of Heat Canning of Hydrobionts of the Far Eastern Seas, Dal’nauka, Vladivostok, 1-270

Syromyatnikova MG 1964 Method of microbiologic and Sanitary searches of Fish Products The Far Eastern Publishing, Vladivo- stok, 1-160

Re-amount of polyunsaturated fatty acids in canned seafood with

added spice-oil extract was significantly higher than that in

all assortments of canned goods with added vegetable oils

This suggests that the longer duration of sterilization

neces-sary for the control samples alters the fatty acid composition

of oils Fatty acids with shorter carbon chains are formed

during the destruction of fatty acids

The destructive changes in the fatty acid composition of

the oil component increased with increasing temperature

treatment duration The thermal processing of canned

sea-food at 115°C for an additional 5 min led to the destruction of

polyunsaturated fatty acids in canned goods (corn oil, 5.5%;

sunflower oil, 8.2%; soybean oil, 9.1%) (Table 4)

Destruction of polyunsaturated fatty acids was greater

in the oils of control samples compared to experimental

samples (smoked sea cucumber in oil); e.g., sunflower oil

(10.5%) and olive oil (10.8%).

The blending of oils promotes an increase in the

resis-tance of the oil components of canned seafood against the

action of heat during sterilization, especially when spice-oil

extract is used In seafood canned with a blend of soybean

oil and corn oil (55:45) and sterilized for an additional 5 min,

the polyunsaturated fatty acid content was reduced by 2.9%

compared to that in goods canned with the spice-oil extract

The 10-min reduction in the sterilization duration of seafood

canned with an oil mixture or with spice-oil extract promotes

the preservation of polyunsaturated fatty acids by 8%

com-pared to goods canned with vegetable oil

In conclusion, in the manufacture of canned seafood, the

substitution of spice-oil extract for vegetable oil reduces the

heat resistance of microbial spores, hence enabling effective

sterilization of canned goods at 115 ° C for a shorter period

of time, that is, by 5 to 10 min for canned goods with added

spice-oil extract This 5-10-min reduction in the duration of

sterilization at 115 ° C of goods canned with spice-oil extract

can reduce thermal damage to the major constituent nutrients

while maintaining the digestibility of the protein component.

Acknowledgments

This work was supported by a grant from National

Fisher-ies Research and Development Institute of Korea

(RP-2014-FS-032).

References

AOAC 1995 Official methods of analysis, 16th ed Association of

Of-ficial Analytical Chemists Washington, DC, U.S.A., 69-74.

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