SINGLE CELL PROTEIN mycelial fungi

Tổng quan đánh giá về các sản phẩm protein đơn bào (SCP) từ nấm mốc. Lựa chọn hệ nấm mốc trong công nghệ sản xuất Protein đơn bào. Cải tiến công nghệ sản xuất protein đơn bào. Đánh giá chất lượng Protein trong SCP được sản xuất từ nấm mốc.

Mycelial Fungi

The Algae

Yeasts and Bacteria

Mycelial Fungi

PS Nigam,University of Ulster, Coleraine, UK

A Singh,Technical University of Denmark, Lyngby, Denmark

Ó 2014 Elsevier Ltd All rights reserved

This article is a revision of the previous edition article by Poonam Nigam, volume 3, pp 2034–2044, Ó 1999, Elsevier Ltd

Introduction

The extent of shortfall in protein varies from country to country

and must be considered within the framework of each national

economy The shift from grain to meat diets in industrial and

developing countries is of dramatic proportions and leads to

a much higher per capita grain consumption, since it takes

3–10 kg of grain to produce 1 kg of meat by animal rearing and

fattening programs

The experimental use of microbes as protein producers has

been widely successful Thisfield of study has become known

as single-cell protein (SCP) production, referring to the fact that

most microorganisms used as producers grow as single or

filamentous individuals rather than as complex multicellular

organisms, such as plants or animals

Eating microbes may seem strange, but people have long

recognized the nutritional value of the large fruiting bodies of

some fungi, that is, mushrooms Mushroom growing, because

of its antiquity, can be considered a conventional type of food

production This article is concerned with novel processes for

growing fungal mycelia, which lend themselves to

biotechno-logical processing

The pioneering research on SCP production, conducted by

Max Delbriick and coworker in Berlin, about one century ago,

highlighted the potential use of surplus brewer’s yeast as

a feeding supplement for animals The term SCP was coined in

the 1960s to embrace microbial biomass produced by

fermen-tation The SCP production technologies developed as a

prom-ising way to cultivate enough protein for the world’s protein

hunger Over the past two decades, there has been a growing

interest in using microbes for food production, in particular for

feeding domesticated food-producing animals such as poultry

Use of SCP derived from low-value waste materials for animal

feed may increase the food available to humans by reducing

competition between humans and animals for protein-rich

vegetable foods Major companies throughout the world have

long been involved in developing SCP processes, and many SCP products are now commercially available

SCP may be used as a protein supplement, as a food addi-tive to improveflavor or fat binding, or as a replacement for animal protein in the diet Microorganisms have high DNA and RNA contents and human metabolism of nucleic acids yields excessive amounts of uric acid, which may cause kidney stones and gout Because humans have a limited capacity to degrade nucleic acids, additional processing is required before SCP can

be used in human foods In animal feeding, SCP may serve as

a replacement for such traditional protein supplements asfish meal and soy meal The high protein levels and bland odor and taste of SCP, together with ease of storage, make SCP a poten-tially attractive component of manufactured foods Also its high protein content makes it attractive for feeding farmed crustacea andfish

Significance of Single-Cell Protein

Microorganisms produce protein much more efficiently than any farm animal (Table 1) The yields of protein from a 250 kg cow and 250 g of microorganisms are comparable The cow will produce 200 g of protein per day, whereas the microbes, in theory, can produce 25 tons in the same time under ideal growing conditions

The advantages of using microbes for SCP production are outlined inTable 2

Choice of Mycelial Fungi in Biotechnology

Currently, fungi are used for the production of secondary metabolites of medicinal and industrial importance (antibi-otics, mycotoxins, and fermented foods) Filamentous fungi also play a significant role in the food industry, for example, adding flavor to certain cheeses and in the production of

oriental foods (Table 3) They are used as a major protein

source in some food additives and extenders and to improve

the protein content of animal feeds

In the previous examples, thefilamentous fungi, although

playing an important role, are generally a minor component of

thefinal product It is possible, however, to utilize the physical

characteristics of these fungi to assemble structured food

products whose sensory textures are similar to muscle tissue

food products An example of this approach is given in the

following section

Texture and Flavor of Mycoprotein

In addition to the growth rates of organisms used for SCP, their conversion of substrate to protein is much more efficient than conversion of feed by farm animals This is shown inTable 4 Thefilamentous morphology of the fungi means that the mycelial mass has a natural texture, which can be used to impart a meatlike texture to the product, which may also be favored and colored to resemble meat The coarseness of the texture depends on the length of the hyphae, which can be controlled by adjusting the growth rate

Commercial Exploitation of Mycelial Fungi

The following characteristics determine the choice of fungi as organisms to be used in a large-scale industrial fermentation process, producing a low-costfinal product:

l Good at breaking down a wide range of complex substrates (e.g., cellulose, hemicellulose, pectin)

l Can tolerate low pH values, which helps in preventing contamination of the culture

l Few nutritional requirements

l Ease of recovery of biomass byfiltration

l Ease of handling and of drying the biomass

l Structure conferred by hyphae allows the fabrication of textured foods

The industrial production of SCP continues to excite attention, particularly in relation to the use of simple carbo-hydrates as feedstock for microbial growth and biomass production Today, however, the economics of production has shifted the emphasis from the application of SCP to solve the problem of starvation to the production of novel foods for use

in advanced economies

Features of Commercial Exploitation of Fungi

Following are the features of commercial exploitation:

l Rapid growth rate and high protein content compared with plants or animals

l Can be produced in large amounts in a relatively small area, using biological by-products as sources of nutrient, such as the by-products from the confectionery and distillery, vegetable and wood-processing industries, although for human food application, the use of food or reagent-grade nutrients is essential

l Fungal cells contain carbohydrate, lipids, and nucleic acids, and a favorable balance of lysine, methionine, and trypto-phan amino acids that plant proteins often lack

For example, fungi can be used to improve the nutritional quality of food grains, such as barley Barley is deficient in lysine, which is normally added to barley feed in the form of expensive proteins such asfish or soy meal Fungal supple-mentation is achieved by adding a nitrogen source to a barley gruel and then inoculating it with an amylolytic (starch-decomposing) fungus, such as Aspergillus oryzae or Rhizopus arrhizus The barley starch is hydrolyzed to glucose and the protein content increases as the fungus grows Expensive

Table 1 Time required to double the mass

of various organisms

Table 2 The advantages of using microbes for single-cell protein

production

1 Microorganisms can grow at remarkably rapid rates under optimum

conditions; some microbes can double their mass every 30–60 min

2 Microorganisms are more easily genetically modified than plants and

animals; they are more amenable to large-scale screening programs to

select for higher growth rate and improved RNA content and can be

subjected more easily to gene transfer technology

3 Microorganisms have a relatively high protein content and the

nutri-tional value of the protein is good

4 Microorganisms can be grown in vast numbers in relatively small

continuous fermentation processes, using a relatively small land area,

and growth is independent of climate

5 Microorganisms can grow on a wide range of raw materials, including

low-value agri-industrial residues and by-products

6 The production is independent of seasonal and climatic variations

Table 3 Direct food uses of fungi

Edible macrofungi

Volvariella volvacea Chinese or straw mushroom

Cheeses Penicillium roqueforti Roquefort, stilton, blue

Penicillium camemberti Camembert, brie, soft-ripened cheeses

Oriental food fermentations Monascus purpureus Ang-kak, anka koji, or beni koki

(red rice– culture grown on rice grains) Aspergillus oryzae/A sojae Miso (fermented soybeans)

Aspergillus oryzae/A sojae Shoyu (soy) sauce

Rhizopus oligosporus Tempeh or tempe kedele

(fermented soybean cotyledons)

sterilization steps are not required at any stage of the process

and the product provides an ideal feed for use in pig production

Growth Rates of Fungi

Although fungi usually grow more slowly than bacteria or

yeasts, the data inTable 5show that, for the practical

consid-eration of biomass production, the growth rates of fungi can be

adequate

Composition of Fungi and Nutritional Values

The nutritional value of fungal protein has been shown to be very satisfactory and compares well with protein from yeasts and bacteria The compositions of some of the important fungi used for biomass production are shown inTable 6 The dis-tinguishing feature of fungal composition lies in the distribu-tion of the nitrogen content Crude protein values based on total nitrogen 6.25 can be misleading for SCP, because of the RNA content of microbial cells and because fungi have

Table 4 Myco- and animal protein: conversion rates in protein formation

Table 5 Maximum specific growth rates (mmax) of filamentous fungi used for biomass production

Table 6 Analysis of fungi for protein production (all values are in % dry weight)

Fermentation substrate

Culture type (FP) Fungi

Crude protein (total N 6.25)

True protein nitrogen

Nonprotein

CMI 138291

substantial amounts of their nitrogen as n-acetylglucosamine in

chitin of the cell wall The protein content of the cells is

approximately two-thirds of the total nitrogen, whereas RNA

accounts for 15% and chitin for 10% The chemical

composi-tion of single-cell biomass is not fixed; it varies with the

limiting substrate, culture conditions, growth rate,

tempera-ture, and pH Biomass is grown for its protein content and

therefore is never produced under nitrogen limitation; in

consequence, the lipid content of the cells is almost invariably

low, because fungal cells tend to synthesize maximum lipid

content only under nitrogen limitation

SCP Production Method

The central operation in SCP production is fermentation, for

optimum conversion of substrate to microbial mass (Table 7)

Any such operation requires the specification of the medium

and the growth conditions, the design and operation of

a suitable fermentation vessel and associated control systems,

and the separation of the cell mass from the fermentation

broth On a commercial scale, SCP invariably is produced in

submerged liquid culture Batch or continuous culture

techniques may be used Continuous culture, which offers considerable advantages in terms of overall productivity of the fermentation processes, has been the chosen method of production in commercial SCP systems On a commercial scale, this requires specialized plant, which is able to with-stand initial sterilization procedures before each production is run and which has sensorsfitted into the vessel to monitor the parameters of the process

RNA Reduction Processes

To meet the 1976 requirements of Food and Agricultural Organization/World Health Organization PAG (1976) and to limit the ingestion of RNA from nonconventional food sources

to 2 g per day, various methods of RNA reduction have been investigated:

1 Alkali extraction lowers the RNA levels of the mycelium Treatment of proteins with alkali can lead to the formation

of the dipeptide lysinoalanine, which is undesirable in food materials, and care has to be exercised to prevent this from occurring It was claimed that the use of alkali

Table 7 Fermentative production of fungal protein

Carbon and energy

Temperature

Specific growth rate (m) or dilution rate (D: h1)

Culture densitya (g l)

Mycelial yieldag per g substrate Supplied Used Glucose, citrus press

water, orange juice

Malt syrup cane

molasses

Coffee waste water 5000 gal

(18 927 l) tank

Brewery waste,

grain press liquor

Brewery waste, trub

press liquor

Corn and pea waste 37 854 l aeration

pool

Corn and pea waste 189 270 l pool

(continuous)

Gliocladium deliquescens

Cheese whey, corn

canning waste,

sulfite liquor,

pumpkin

Cheese whey, corn

canning waste

a

extraction improved the consistency, color, and odor of

Pekilo protein biomass if the alkali was neutralized with

acid before washing Care had to be taken to ensure that

the pH did not fall below 6.0, as this caused RNA to be

reprecipitated on to the biomass and hence increased the

RNA level of recovered cells

2 Endogenous enzymic hydrolysis reduces the RNA levels

from 9% to less than 2%

3 Heat shock at 64 C inactivates the fungal protease and

allows the endogenous RNases to hydrolyze the disrupted

ribosomal RNA

Recovery of Biomass from Culture Broths

One of the major advantages possessed by the filamentous

fungi over single-celled organisms is the ease with which the

former can be separated from the culture medium On

a small scale,filtration using filter paper and Buchner funnels

usually is adequate For larger volumes, a low-speed,

perfo-rated-bowl centrifuge gives good results On a large scale,

rotary vacuumfilters are the method of choice; nylon filter

cloths of suitable retentivity can normally recover>99.9% of

biomass mycelium and provision may be made for spray

washing as part of thefiltration operation; biomass removal

is done by scraper blade With a vacuum of 60–65 cm Hg,

filtration rates of around 70–80 kg m2h1from a medium

containing 20% total solids are achievable To reduce

subsequent costs of drying if required, various dewatering

equipment can further reduce the 80% water content offilter

cake Continuous screw expellers of the type used in the

brewing industry for dewatering spent grains can be used

High-volume throughput necessitates continuous

equip-ment In the Pekilo process, mechanical dewatering produces

a material of 35–45% total solids

Drying

Fungal biomass is easy to dry because its structure does not

tend to collapse and lead to case hardening, as does bacterial

biomass Using a continuous band drier with single-pass

warm-air downflow, an air temperature of 75C is optimal for drying

a Penicillium mycelium ex-vacuumfilter at 20% solids; a

resi-dence time of 20–30 min produces a product of 8–10%

moisture Heating at too high a temperature reduces the

nutritional value of the product because of alteration in lysine

availability Other forms of simple driers such as rotary drum

driers are also applicable

General Product Specifications for SCP

as Human Food

Important aspects of the product quality of SCP include the

following:

l Nutritional value

l Safety

l Production of functional protein concentrates

Digestibility ( D )

D is the percentage of total nitrogen consumed that is absorbed from the alimentary tract The total quantity of microbial protein ingested by animals is measured and the nitrogen content (I) is analyzed Over the same period, feces and urine are collected, and fecal nitrogen content (F) and urinary nitrogen content (U) are measured Thus

D ¼ I  FU 100

Biological Value (BV)

BV is the percentage of total nitrogen assimilated that is retained by the body, taking into account the simultaneous loss

of endogenous nitrogen through urinary excretion Thus

BV ¼ I  ðF þ UÞI  F  100:

Protein Efficiency Ratio (PER)

PER is the proportion of nitrogen retained by animals fed the test protein compared with that retained when a reference protein, such as egg albumin, is fed

Preservation of Mycoprotein

Preservation is by freezing or chill storage

Testing mycoprotein for nutritive value and safety has been extensive and in 1985 resulted in permission being granted by the Ministry of Agriculture, Fisheries and Food for free sale of mycoprotein in the United Kingdom

Commercial Production of Mycelial Protein Pekilo Process

Pekilo is a fungal protein product produced by fermentation of carbohydrates derived from spent sulfite liquor, molasses, whey, waste fruits, and wood or agricultural hydrolysates It has

a good amino acid composition and is rich in vitamins Extensive animal feeding test programs showed that Pekilo protein is a good protein source in the diet of pigs, calves, broilers, chickens, and laying hens Pekilo protein is produced

by a continuous fermentation process The organism, Paecilo-myces variotii, a filamentous fungus, gives a good fibrous structure to thefinal product The first plant was installed at the Jamsankoski pulp mill in central Finland in 1973 As an animal feed component, Pekilo protein is comparable to fodder yeast, which is also produced by fermenting spent sulfite liquor

Mycoprotein Production

In the UK Rank-Hovis-McDougall, in conjunction with Imperial Chemical Industries (ICI) (in 1993, ICI demerged into Zeneca and became the new ICI) commercially

marketed another fungal protein, mycoprotein (Quorn),

derived from the growth of a Fusarium fungus on simple

food-grade carbohydrates Unlike almost all other forms of

SCP, mycoprotein is produced for human consumption

Technical Development of Mycoprotein and Quorn

Marlow Foods, based in the United Kingdom, is involved in the

development, production, and marketing of a range of Quorn

consumer food products made with mycoprotein Marlow

Foods is a subsidiary of Zeneca Group PLC

Mycoprotein is the generic name of the major raw material

used in the manufacture of Quorn products It is composed of

RNA reduced cells of the Fusarium species (Schwabe) ATCC

20334, grown under axenic conditions in a continuous

fermentation process.Table 8shows the history of the

devel-opment of commercial Quorn mycoprotein

Quorn, the brand name of a range of meat-alternative

prod-ucts using mycoprotein as the principal component (Table 9), is

Table 8 History of commercial mycoprotein

1965 The search is started for mycoprotein foods by Rank-Hovis-McDougall with ICI

1967 The microorganism used for production of mycoprotein is identified as Fusarium graminearum

1969 Initial work is begun intoflavor and texture of mycoprotein

1975 Pilot development production facility is set up

1985 Ministry of agriculture,fisheries and food acceptance in the United Kingdom

1986 Marlow Foods formed The Quorn brand name launched First ever mycoprotein retail product– a vegetable pie

1990 First home-cooking product launched: Quorn pieces

1992 First European launch in Benelux countries

1996 Mycoprotein products launched in Switzerland

1997 Product range exceeds 50 items in UK supermarkets

1998 Expansion of product range in the United Kingdom and Europe

Development in other countries Available in markets of the United Kingdom, Belgium, Switzerland, the Netherlands, and Ireland

2002 Mycoprotein products launched in the United States

2003 Mycoprotein products launched in France

2004 McDonald’s introduced a Quorn-branded burger bearing the seal of approval of the vegetarian society

2005 Quorn replaced around 60% of the meat products in UK food market by their products based on mycoprotein

2006 Mycoprotein products available in stores in the United Kingdom, Spain, Belgium, Sweden, the Netherlands, the United States,

Switzerland, and the Republic of Ireland

2010 Mycoprotein products launched in Australia

2011 Quorn foods launched a‘vegan burger’ into the US market

Table 9 Commercial food products made from mycoprotein which are available in the UK supermarkets

Chilled products Q pieces, Q mince, Q nuggets, Q chilled sausages, peppered Q steak, crunchy Qfillets garlic and herb, lemon and black pepper

crisp crumb Qfillets, Q oriental fillets, Q steak Diane, Q lamb-flavor grills, Q en crûte, Q fillets, Q creatives Thai, Q creatives Italian, Q bolognese, Qfillets in a tomato, red wine, and mushroom sauce, Q fillets in white wine and mushroom sauce, Q BBQ burger, tikka pieces, Q salmon style dill crispbakes, Q tuna style melt,fish less fingers, tuna style and sweet corn crispbake, sizzling BBQ bangers, sizzling burger, sweet and sour crispy bites

Deli products Roast beef-style, smoked chicken-style, honey roast ham-style, garlic sausages-style, turkeyflavor with stuffing, new Q rashers,

bacon style, wafer thin ham style, chicken style, smoky ham style slices, roast chicken style slices, ham style, smoky bacon style slices, peppered beef style slices, turkey style with stuffing

Ready meals Q lasagna, Q tikka masala, Q oriental stir fry, Q cottage pie, Q mushroom pie, Q korma, Q spicy light bites, Q roasted light bites,

sundried tomato toppedfillet, spaghetti and balls, lasagne, sweet and sour, Q mini savory eggs, lamb style grills, breaded goujons, crispy chicken style nuggets, Swedish style balls, Q satay skewers

Frozen products Q burgers, Q quarter pounders, Q premium burgers, Q southern-style burgers, Q sausages, Q pieces, Q mince, new Q dippers,

new Q lasagne, new Q chili,fillets in tomato and olive sauce, Q chicken style pieces, Q barbeque slices fillets, Q tikka slices fillets, sausage lattice

Q, Quorn brand name.

Sterilized nutrients and minerals Fermenter

Chillers

Mycoprotein

Centrifuge

Services

Figure 1 Schematic of the mycoprotein fermentation process

registered to Marlow Foods These products are sold throughout

the United Kingdom and increasingly in western Europe

Quorn products are a good source of protein, are lower in

calorific value (89 kcal per 100 g), and have a higher dietary

fiber content than their natural meat equivalents They contain

no animal fats or cholesterol and have a high level of dietary

fiber They can be eaten by anyone, although they are not

rec-ommended for very young children because of their low energy

density Quorn products have a tender texture similar to that of

lean meat This makes them attractive to vegetarians who miss

the taste of meat, as well as to consumers who are reducing

their red meat intake

The cells are grown by continuous aerobic fermentation

(Figure 1) for periods up to 1000 h of continuous operation

The plant is sterilized between operating runs by the use of

steam under pressure

The substrate, glucose syrup, and all the nutrients added to

the fermenter are sterile and of food or reagent-grade quality

The water is purified before it is used in the fermenter The pH in

the fermenter is controlled by the injection of ammonia, which

also provides part of the nitrogen source for the cells

A continuous spill from the fermenter carries away the biomass

produced: Theflow rate is such that the volume of the fermenter

is displaced every 5–6 h The cell suspension is then taken to

a continuously stirred tank reactor held at approximately 65C,

to reduce the RNA content (dry weight) from 10% to less than

2% The suspension is then heated to 90C, and dewatered by

centrifugation before being cooled The harvested cells,

collec-tively known as mycoprotein, are pastelike in consistency and

contain around 75% moisture

Commercial Production of Mycoprotein Food

Products

The harvested cells have a similar morphology to animal

muscle cells– they are filamentous with a high

length–diam-eter ratio, length 400–700 mm, diameter 3–5 mm, and branch

frequency 1 per 250–300 mm (Figure 2) The product assembly

process seeks to reproduce the structural organization that

exists in natural meats

In meat, muscle cells are held together by connective tissue

To establish a similar product texture in Quorn products, the

cells are mixed with a protein binder, together withflavoring

and other ingredients, depending on thefinal product format,

and then heated (Figure 3) This causes the protein binder to

gel and bind the cells together The resultant structure is very

meatlike in appearance, texture, and formed products such as

steaks orfillets

Developing Texture

The ingredients added differ according to the product

produced The mixture is transported to a forming machine, set

up for the product being produced For Quorn pieces and

mince the forming machine produces strips of Quorn, which

then are reduced in size The next step is to steam the mixture

The high temperatures reached during steaming affect gelation

of the albumen, which is added at the mixing stage; this in turn

improves the texture of the product by increasing firmness

After steaming, the products are cooled rapidly, before weigh-ing, packweigh-ing, and storage

Characteristics of Mycoprotein Products Good Source of Dietary Fiber

Because Quorn food products contain 60–90% of mycopro-tein, there will be a corresponding significant dietary fiber content in thefinal product Mycoprotein contains 5.1 g die-taryfiber per 85 g (Table 10) Fiber includes 65%b-glucans and 35% chitin, and, of this, 88% is insoluble and 12% soluble

No Interference with Mineral Absorption

Quorn products do not contain phytic acid or phytic salts that may interfere with mineral absorption No significant effect

on the absorption of calcium, magnesium, phosphorus, zinc,

or iron has been shown in comparison with a polysaccharide-free diet

Lower in Fat, Saturated Fat, and Cholesterol than Equivalent Meat Products

Mycoprotein contains only 2.6 g fat and 0.5 g saturated fat per

85 g (Table 10) It does not contain any trans fatty acids (Table 11) Quorn products, however, may contain slightly higher levels of fat and some trans fatty acids, as small Figure 2 Micrograph of mycoprotein illustrating itsfilamentous nature

amounts of fat may be added to enhance the taste and texture These products contain between 2.4 and 8.4 g fat and 0.4– 2.4 g saturated fat per 85 g cooked weight In comparison, equivalent meat products contain 2.5–3.5 times more fat and saturated fat

Rich in Protein Content

Quorn products typically contain between 10 and 13 g of protein per 85 g serving, most of which comes from myco-protein Small amounts come from egg albumen and milk proteins, which are added in the manufacturing process The

Mycoprotein

Steaming

Ingredients

Metal detection

Weigh and bag

Texturizing

Cutting (if required)

Chilling

Boxing

Shrink wrap

Deep freeze hold

Cold store

Distribution for sale

Figure 3 Schematic of the manufacturing process for Quorn products

Table 10 Nutrition comparison: mycoprotein compared with other sources of dietary protein

Food type

Measure (g)

Energy (kcal)

Protein (g)

Total carbohydrate (g)

Dietary fiber (g)

Total fat (g)

Fat breakdown (g)

Cholesterol (mg) Saturated Mono Poly

Ground beef: regular, medium

baked

Table 11 Fatty acid profile of mycoprotein (fat content ¼ 3 g per

100 g)

Fatty acid

Grams per 100 g fat in

mycoprotein

Grams per 100 g mycoprotein

C18:3

a-Linolenic

nutritional advantages of Quorn products (Table 12) include

the fact that they are excellent sources of high-quality protein

but are significantly lower in fat, saturated fat, and calories than

many protein foods

High-Quality Protein

Dietary proteins contain a mixture of 20 amino acids, all of

which are necessary to support growth Although most amino

acids can be made in the body, nine essential amino acids must

be supplied by the diet: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine The quality of a dietary protein is based on its content of essential amino acids Table 13 compares the amino acid content of mycoprotein with other commonly consumed protein foods The PER for mycoprotein is 2.4, BV 84, and D 78 A recent development in the United States required by the Food and Drug Administration is that the protein digestibility-corrected

Table 13 Essential amino acid content of mycoprotein compared with other foods that contain protein (g amino acids per 100 g edible portion)

a

Whole fluid milk (3.3% fat).

b

Raw fresh egg.

c

Ground beef (regular, medium baked).

d

Mature raw soybeans.

e

Raw peanuts (all types).

f Durum wheat.

g Chicken, broilers or fryers, back, meat and skin, cooked, stewed.

Source: U.S Department of Agriculture Nutrient Data Base for Standard Reference, 12 March 1998.

Table 12 Protein, fat, and calorie content of selected commercial mycoprotein food products compared to meat equivalents

Food (per 100 g cooked portion) Protein (g) Carbohydrate (g) Total fat (g) Saturated fat (g) Calories (kcal) Energy density (kcal)

amino acid scoring (PDCAAS) method must be used for most

nutrition labeling purposes This method takes into account

the food protein’s essential amino acid profile, its digestibility,

and its ability to supply essential amino acids in amounts

required by humans It compares the essential amino acid

profile of a food, corrected for digestibility, to the Food and

Agricultural Organization/World Health Organization 2- to

5-year-old essential amino acid requirement pattern The 2- to

5-year-old pattern is used because it is the most demanding

pattern of any age-group other than infants

The PDCAAS for mycoprotein is 0.91, based on a

digest-ibility factor of 78% for mycoprotein.Table 14 shows how

mycoprotein compares with the PDCAAS of other food

proteins

Mineral and Vitamin Composition

Mycoprotein used in Quorn products compares well in mineral and vitamin composition with other sources of dietary protein (Table 15) The PDCAAS value for Quorn products (which all contain egg albumin) is 1

See also: Aspergillus: Aspergillus oryzae; Fermentation (Industrial):Production of Oils and Fatty Acids; Mycotoxins: Classification

Further Reading Anke, T (Ed.), 1997 Fungal Biotechnology Chapman & Hall, London Atkinson, B., Mavituna, F., 1991 Biochemical Engineering and Biotechnology Hand-book, second ed Macmillan, New York

Denny, A., Aisbitt, B., Lunn, J., 2008 Mycoprotein and health British Nutrition Foundation Nutrition Bulletin 33, 298–310

Higgins, I.J., Best, D.J., Jones, J (Eds.), 1988 Biotechnology Principles and Appli-cations Blackwell Scientific Publications, Oxford

Khan, M., Khan, S.S., Ahmed, Z., Tanveer, A., 2009 Production of fungal single cell protein usingRhizopus oligosporus grown on fruit wastes Biological Forum 1 (2),

32–35 PAG Ad Hoc, 1976 Working group meeting on clinical evaluation and acceptable nucleic acid levels of SCP for human consumption PAG Bulletin 5 (3), 17–26 Sarwar, G., McDonough, F.E.C., 1990 Journal of the Association of Official Analytical Chemists 73, 347–356

Smith, J.E., 1996 Biotechnology, third ed Cambridge University Press, Cambridge Solomon, G.L., 1985 Production of filamentous fungi In: Moo-Young, M (Ed.), Comprehensive Biotechnology, vol 3 Pergamon Press, Oxford

Wainwright, M., 1992 Fungi in the Food Industry An Introduction to Fungal Biotechnology John Wiley, Chichester

Relevant Website http://www.quorn.co.uk/– Quorn

Table 14 Protein digestibility corrected amino acid score (PDCAAS)

of selected food proteins

a: Food and Agriculture Organization/World Health Organization Joint Report (1989).

b: Sarwar and McDonough (1990).

c: Calculated from amino acid data in the US Department of Agriculture Data Base

for Standard Reference, 12 March 1998 (assumes a digestibility equivalent to

beef ¼ 94%).

d: Calculated from Marlow Foods data.

Table 15 Vitamin and mineral comparison: mycoprotein compared with other sources of dietary protein

Food type

Measure (g)

Ca (mg)

Fe (mg)

Mg (mg)

P (mg)

K (mg)

Na (mg)

Zn (mg)

Vitamin A (mg)

Thiamin (mg)

Riboflavin (mg)

Niacin (mg)

Vitamin B6 (mg)

Folic acid (mg)

Vitamin C (mg)

Ground beef: regular,

medium baked

Chicken: light meat,

roasted

RE, retinal equivalent.