Research on the production process of candied orange slices product

The thesisobjectives are research on the effects of bitter elimination method, the ratio ofmixing sugar and orange, the effects of temperature and drying time, the quality ofthe product

THAI NGUYEN UNIVERSITY OF AGRICULTURE AND FORESTRY

ADVANCED EDUCATION PROGRAM

: Full-time : Food technology : Advanced education program : 2016 - 2020

Thai Nguyen, 2020

THAI NGUYEN UNIVERSITY OF AGRICULTURE AND FORESTRY

ADVANCED EDUCATION PROGRAM

Supervisor(s)

: Full-time : Food technology : Advanced education program : 2016 - 2020

: MSc NGUYEN ĐUC TUAN

Thai Nguyen, 2020

Thai Nguyen University of Agriculture and Forestry

product

Agriculture and Forestry, Vietnam

Supervisor’s

Abstract: Oranges contain many benefits to the human body such as a rich source ofvitamin C, fiber, low in calories, and boosting cardiovascular health, However,fresh oranges are very roots damaged during transportation and storage due tophysiological activities, biochemistry, and microorganisms The purpose of thisstudy is to process candied orange slices from some types of orange in Vietnam withgood nutritional value and good sensory value, contributing to diversifying to theseproducts on the market and increasing income for orange growers The thesisobjectives are research on the effects of bitter elimination method, the ratio ofmixing sugar and orange, the effects of temperature and drying time, the quality ofthe product candied orange slices during storage time, and establish a process forprocessing products candied orange slices We used sensory methods to assess thequality of products and used SPSS software to aggregate data The results showedthat: the bitter elimination method by soaking fresh orange in 5% salt-water, theratio of mixing orange and sugar was 2.0:1.0, the drying temperature was 55°C for

24 hours to create a product with a safe humidity of 7.5%, Identify changes inproduct during storage and product retention time for moisture, total soluble solidscontent, total sugar content, total organic acid content, vitamin C content,

%, 16.85% And then, set up a production process of candied orange slices productwith all accompanying technology parameters

Candied orange slices, drying method, production process,

First of all, I am grateful to the Thai Nguyen University of Agriculture andForestry, the Advance Education Program, the Faculty of Biotechnology and FoodTechnology, where have taught and imparted necessary knowledge and valuableexperience to me, during the time I studied and researched at Thai Nguyen University

of Agriculture and Forestry

I really want to show my deeply grateful to my supervisor Mr Nguyen Duc Tuanfor his conscientious contribution and useful suggestions during the planning anddevelopment of my research work His precious critiques helping me to understandhow to complete my graduation thesis Once again I sincerely thank my supervisor andwishing good health for him

I am also thankful to Ms Le Thi Thu Hien, Ms Nguyen Thi Tra, Mr Le Sy Luy,and Ms Chu Thi Nhan who willing to give me a hand when I do the thesis in theLaboratory of Faculty of Biotechnology and Food Technology

I also acknowledge with a deep sense of reverence with all members of my familywho are always to help and encourage me on the completion of this thesis

I also would like to thank all of my friends who directly or indirectly helped me

to complete this thesis

However, due to the limited knowledge and the lack of practical experience, thecontent of the thesis cannot avoid shortcomings, I would like to receive furthersuggestions and advice to make my this thesis is more complete

Best regards

Thai Nguyen,

Le Thu Thuy

TABLE OF CONTENT

ACKNOWLEDGEMENT i

TABLE OF CONTENT ii

LIST OF FIGURES iv

PART 1 INTRODUCTION 1

1.1 Research rationale 1

1.2 Research’s objectives 2

1.3 Research questions and hypotheses 3

1.4 Limitations 3

1.5 Definitions 3

PART 2 LITERATURE REVIEW 4

2.1 The scientific basis of the thesis 4

2.2 The importance of the orange industry to people and the economy 14

2.3 The situation of orange production and consumption in Vietnam and worldwide 16 2.4 Products made from oranges 19

2.5 General process of producing candied orange slices 21

PART 3 CONTENTS AND METHODS 25

3.1 Material 25

3.2 Methods 27

PART 4 RESULTS 32

4.1 Research on choosing the bitter elimination method of fresh orange to product quality 32

4.2 Research on choosing the ratio of orange and sugar to product quality 33

4.3 Research on choosing temperature on product quality 34

4.4 Evaluate the quality of the product candied orange slices finished product 35

4.5 Establish a process for processing product candied orange slices 36

4.5.1 Technology process diagram 36

PART 5 CONCLUSION AND RECOMMENDATIONS 44

5.1 Conclusion 44

5.2 Recommendations 44

REFERENCES 45

ii

LIST OF TABLES

Table 2.1 Physical parameter of a sweet orange fruit 8

Table 2.2 The nutritional composition of fresh orange (USDA) 9

Table 2.3 Summary of the composition, percentage, nutritional value, and pharmacological effects of each orange composition 11

Table 2.4 Sensory indicators of sugar 12

Table 2.5 Sensory requirements of sodium chloride 13

Table 2.6 Sensory requirements of honey (TCVN 12605: 2019) 14

Table 3.1 Research instruments and equipment 25

Table 3.2 Chemicals 26

Table 3.3 Research on choosing the brine solution to the bitter elimination method of fresh orange 27

Table 3.4 Research on choosing the ratio of orange and sugar to product quality 28

Table 3.5 Research on choosing drying temperature on product quality 28

Table 4.1 Results for research on choosing the bitter elimination method of fresh orange to product quality 32

Table 4.2 Result for research on choosing the ratio of orange and sugar to product quality 33

Table 4.3 Results for research on choosing the temperature and drying time on product quality 34

Table 4.4 The content of nutrients and microbiological criteria in candied orange slices products 35

Table 4.5 Preparation the ingredients 38

LIST OF FIGURES

Figure 2.1 Sanh orange and Vinh orange 4

Figure 2.2 Xa Doai orange 5

Figure 2.3 Navel orange 6

Figure 2.4 Sanh orange 7

Figure 2.5 Sweet orange 7

Figure 2.6 Area planted oranges in Vietnam from 2005 to 2018 16

Figure 2.7 Orange production in Vietnam 16

Figure 2.8 Orange production worldwide from 2012/2013 to 2018/2019 18

Figure 2.9 Leading orange producing countries worldwide in 2018/2019 19

Figure 3.1 Drying oven 27

Figure 4.1 The main materials: Chanh orange and Sugar 38

Figure 4.2 Washing fresh orange 38

Figure 4.3 Cutting slices orange and remove the seed 39

Figure 4.4 Soaking the sliced orange in brine water 39

Figure 4.5 Soaking in lime water 40

Figure 4.6 Mixing with sugar 40

Figure 4.7 Concentrate by boiling sugar solution 41

Figure 4.8 Drying orange pieces bt đrying oven 42

Figure 4.9 Packaging the candied orange slices product 42

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PART 1 INTRODUCTION

1.1 Research rationale

Vegetables and fruits are indispensable foods in the human diet They provideessential nutrients for the growth of the body and strengthen the immune system,prevent diseases such as cardiovascular disease, blood pressure, stroke, etc [1], [3].Fruits and vegetables also play an important role in human nutrition and health, such

as sources of vitamin C, vitamin B1, vitamin B3, vitamin B6, vitamin B9, minerals,dietary fiber (Wargovich, 2000) In Vietnam, fruits and vegetables are a source of foodfor the human, and economic source of the farmer, helping to create jobs, and at thesame time developing Vietnam's economy Currently, Vietnam has exported fruits andvegetables to more than 60 countries around the world, according to the GeneralDepartment of Vietnam Customs, by mid-March 2017, Vietnam's export turnover offruits and vegetables reached nearly $ 543 million, increased by 26.7% over the sameperiod last year [13]

The climate of Vietnam is located in the tropical monsoon region with 4 distinctseasons: Spring, Summer, Autumn, and Winter, the weather of Vietnam is also dividedinto two seasons, rainy and dry Therefore, Vietnam is suitable for many types of fruittrees vary depending on regions such as litchi, jackfruit, avocado, oranges, tangerines,apples, durian, etc In which, oranges grow into specialized areas such as TuyenQuang, Bac Giang, Ha Giang, Hanoi, Hung Yen, Vinh, Nghe An, etc Oranges contentmany benefits to the human body such as a rich source of vitamin C, fiber, low incalories, boosting cardiovascular health, However, fresh oranges are very rootsdamaged during transportation and storage due to physiological activities,biochemistry, and microorganisms, etc Normally, the rate of post-harvest loss inoranges is relatively large from 15-30% and this rate also increases during distributionand storage processing In this situation, the application of post-harvest processingtechniques to reduce the loss of quality of raw materials is essential in Viet Nam [2],[7]

1

Today, on the market there are many types of products made from oranges thatare trusted, such as orange candy, orange juice, orange syrup, orange jam, etc.However, candied orange slices are a product that has not yet been studied and deeplyresearched due to the difficulty of the production process from the processing of rawmaterials to stages of bitter elimination and product completion Candied orange slices

is a product made from thinly sliced fresh orange, reduced the bitterness of the skin,and refine with sugar with a moderate sweetness, supplemented with honey to helpperfect the product flavor that ensures health safety for humans Processing of candiedorange slices is one of the basic measures to preserve fruits, helping to extend thestorage time up to 1 year compared to fresh fruit, giving a completely different productthan the raw material However, in the world, dried fruit jam is applied in productionand trade with materials such as pineapple, bananas, apples, ginger, But the products

of candied orange slice have very little on the market, there is no specific research onthe production of this product according to the production scale

The purpose of this study is to process candied orange slices from some types oforange in Vietnam with good nutritional value and good sensory value, contributing todiversifying to these products on the market and increasing income for orangegrowers Stemming from the above-mentioned reality, I implemented the thesis:

“Research on the production process of candied orange slices” at the laboratory of

The faculty of Biotechnology and Food Technology

1.3 Research questions and hypotheses

1.3.1 Research questions

1.3.2 Research hypotheses

product will have a pertinent sweet taste

safe humidity

1.4 Limitations

limited, cannot be done on a large scale and modern equipment such as the factory

research and experiment

1.5 Definitions

The product "candied orange slice" like Crispy drying jam, with pieces orangeconnect with sugar and dry at high temperature and create to the product with the drymatter around 90%

3

PART 2 LITERATURE REVIEW

2.1 The scientific basis of the thesis

2.1.1 The origin of orange

Oranges with the scientific name are Citrus sinensis belongs to the citrus family.

Oranges vary in size depending on the variety and type Ripe oranges have a sweet andslightly sour taste [8]

There are many different origins regarding the origin of citrus, Orange trees havebeen around for as long as 2200 BC in China, but some argue that oranges are native tothe Himalayas (India) Oranges are very popular in India, then spread to east andsoutheast Asia Around the 3rd century BC, orange trees were brought to Europe andspread to the Mediterranean regions The orange tree was then brought to America byColumbus In the following years, growers in the Americas brought orange trees toAustralinea and Africa Today orange trees are grown very popular in many countries

of the world [8], [9]

Figure 2.1 Sanh orange and Vinh orange

Structure of orange trees:

branches, 2 - 3m tall trees, low branches Spike direction, sparse, horizontal branching

2.5-5cm wide, with a thin tooth edge; petioles with wings, 4-10mm wide Leaves with smallears [9]

- Orange flowers: Oranges often bloom in the spring Each time there are oftenlots of flowers, but only a small number develop fruit Orange flowers are usually white,small, clustered, with a light, pleasant aroma [8].

salts The root system is shallow, broad, and dense, distributed in topsoil and poroussoils The root system grows most strongly in February and September and thrives in thefirst 8 years [17]

sweet, or slightly acidic [20]

Some varieties of oranges are grown in Vietnam:

associated with the place name Vinh (Nghe An, Vietnam) Vinh oranges are round,succulent, yellow evenly The orange color of Vinh orange is bright yellow lemon mixedwith green color There are many varieties of oranges nowadays: Xa Doai orange, Van

Du orange, Song Con orange, Navel orange, etc [8]

origin grown in Vietnam The fruit has two forms, the high fruit and the oval (the fruitare flat) Fruit diameter average 6.8-7.8 cm, the average weight of 200-250gram / fruit,usually with 10-12 pieces, lots of water, 2-3cm thick pods, when ripe, the color peel isbright yellow [8]

Figure 2.2 Xa Doai orange

· Song Con oranges imported by a French plantation owner planted on Dao Nguyenproduction hill (today's Song Con Farm) should be named "Song Con oranges"

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The fruit is very thin skin, lots of water but sweet and also very fragrant Song Conoranges after 3-4 years are the beginning of harvesting, high productivity, goodtolerance to pests and diseases, very suitable for many mountainous midland areas.

through a good selection process, create to orange type with good quality From here takethe breed to other places with name is "Van Du orange" This is a strong, broad canopytree with large, dark green leaves This orange variety produces medium-sized fruits, lots

of water but it contains many seeds The taste of this orange is also special, darkly sweetand slightly bitter taste dissolves quickly after eating

(USA), planted in Vietnam in 1937, are still scattered in farms The average fruit is230g / fruit, can reach 290g / fruit, a diameter of approximately 7.6 cm, when ripe fruit isyellowish gray There are 11 to 12 sections of oranges with dark yellow fruits

Figure 2.3 Navel orange

called Thanh Ha orange, Dong Dinh orange Large fruits (600 - 700g / fruit) on averagealso weigh from 300 - 400g / fruit, 10cm diameter fruit, the skin of the red-yellow fruit.The orange cloves are white color, the seeds big and flat with 20-30 seeds/fruit, sour,bitter taste

We can easily recognize by its thick skin fruit, which is typically bright green Itsflesh is orange, dark, and sweet This is the most popular orange variety in Vietnam.Its flesh is orange, dark, and sweet The most popular orange variety in Vietnam isSanh orange

Typical of king mandarin: Bo Ha oranges, Ha Giang, Tuyen Quang, Yen Bai,

Bo Ha oranges are grown in Bo Ha, Yen The district, Bac Giang province Bo Haorange is suitable with mountainous midland, cool and humid climate

Ha Giang - Tuyen Quang - Yen Bai oranges: are an orange region mainly in thenorthern provinces of Vietnam with high productivity, the fruits are harvested on Tetholiday In Tuyen Quang province, the most famous is Ham Yen orange, this is aregion with delicious oranges

Figure 2.4 Sanh orange

+ Sweet orange (Citrus sinensis L.Osbeck)

The average fruit weighs about 100g, the skin is thin, yellow red or dark red, easy

to peel, easy to divide There are three main types of oranges: Canh orange (Hanoi),Dong Du oranges (Hai Phong), Ngoc Cuc and Hanh Thien oranges (Nam Ha); Buorange, Sour orange, easily planted, slightly sour taste, common in Huong Son (HaTinh), Tuyen Hoa (Quang Binh); Voi oranges (big orange) with big fruits of 300 -350g, hybrid of Bu and grapefruit, planted in Tuyen Hoa (Quang Binh)

Figure 2.5 Sweet orange

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2.1.2 Characteristics of orange fruit

The composition of an orange consists of the following:

The outermost layer (flavedo): orange or blue depending on the breed Theoutermost layer is the layer that contains many essential oil sacs, therefore having astrong flavor similar to that of the orange pulp [17], [20]

The white part of the rind (albedo): contains pectin and cellulose, has nearly thesame amount of vitamin C as the flesh and other nutrients [13], [20]

Carpels with juicy vesicles: the inside contains, the orange cloves are cell fluids

A section of an orange: in it cure the orange cloves and the cell fluid

Orange seeds: hold sprout, include endosperm, embryo, seed coat [9]

Central column: The part located in the center of the orange, containing pectinand cellulose[9]

Table 2.1 Physical parameter of a sweet orange fruit [26]

The compositions of orange

Citrus is a valuable fruit tree on the international market, being one of the most traded fruits Moreover, this is a fruit with high nutritional value

Table 2.2 The nutritional composition of fresh orange (USDA) [33]

Nutritional composition of orange per 100 gram

Nutritional composition of orange per 100 gram

Oranges also contain a lot of fiber, mainly pectin, cellulose, hemicellulose, lignin.The daily supplement of fiber is very beneficial to health, especially improving thefunction of the digestive system and nourishing beneficial bacteria (Metabolic Benefits

of Dietary Prebiotics in Human of National Institutes of Health) Orange is rich invitamins and minerals, especially vitamin C, thiamin, folic acid, and potassium

Eating oranges regularly will help our body be healthier Oranges are rich inflavonoids, especially hesperidin, which helps prevent heart disease effectively(Hesperidin Contributes to the Vascular Protective Effects of Orange Juice by NationalInstitutes of Health) Research has also found that drinking lots of orange juice will

have significant blood thinning and blood pressure reduction (Both Red and BlondOrange Juice Intake Decreases the Procoagulant Activity of Whole Blood in HealthyVolunteers by National Institutes of Health) Iron deficiency is the leading cause ofanemia, which means a decrease in the number of red blood cells or hemoglobin in theblood Although oranges do not contain an abundance of iron, they are rich in vitamin

C, citric acid, etc, which enhances the absorption of iron from the digestive tract.Therefore combining daily oranges supplements will help to prevent anemia [34]

The chemical composition of orange peel

Cellulose is a polymeric polysaccharide that has no sugar properties and is amajor component of plant cells Cellulose is insoluble in water, water inflates a portion

of cellulose It absorbs water with 7-8% by weight

activity

green, naringin causes a bitter taste

Table 2.3 Summary of the composition, percentage, nutritional value, and

pharmacological effects of each orange composition

Composition Percentage (%) Nutritional value and pharmacological effects

stomach painPeel

blood pressure

Vietnam standard for oranges

According to TCVN 1873:2014, we have the following requirements for the

quality of the oranges to produce candied orange slices as follows:

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- Clean, virtually no foreign matter visible to the naked eye;

due to release from the cold storage environment;

The technical requirements of the sugar are as follows (TCVN 6959: 2001):

Table 2.4 Sensory indicators of sugar

Requirement Indicators

strange smellColor

When we mixed sugar withsugar in distilled water to make

a clear solution

relatively clear

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2.1.4 Salt (sodium chloride)

Most kinds of jam on the market such as apple jam, strawberry jam, papaya jam,

… we do not need to use salt in the production process However, the composition oforange peel contains flavonoids, pectin, citric acid, creating a bitter taste of oranges.Therefore, using natural ingredients and salt will help to reduce the bitter taste of theproduct as well as safety to consumers' health [23]

According to TCVN 9639:2013, sensory indicators of salt must conform to therequirements specified in the following table:

Table 2.5 Sensory requirements of sodium chloride [5]

strange taste

2.1.5 Lime water [37]

extracted from the process of dissolving powdered lime (CaO) with water to form amilky solution, leaving the water to settle and take the clear water above

Lime water is used quite a lot in food and is considered safe, helping to make theproduct is crispy, chewy, and clear, creating a perfect taste Although lime water doesnot affect human health, using the right ratio will create a perfect product

2.1.6 Honey

We know that honey is made up of sweeteners collected by the bees Honeycompositions content саrbоhуdrаtе (fructose, glucose, sucrose), water, mineralsubstance, a nitrogen compound, alkaloids, biological stimulants, plant antibiotics,enzyme, organic acid, essential oil, antioxidant, prevent cancer,…

Because of the sweetness and the characteristic aroma of honey, we have usedthem in the production of candied orange slices product However, because the price ofhoney is quite high, so it is used as an auxiliary material and to increase the quality

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of the product Honey used to produce honey must retain the natural, must not mix,and add any ingredients Honey is not heated or processed, because it can cause achange in its composition and quality (TCVN 12605: 2019).

Table 2.6 Sensory requirements of honey (TCVN 12605: 2019)

brown color

2.2 The importance of the orange industry to people and the economy

2.2.1 The importance of the orange industry to people

We know that oranges are rich in nutrients such as vitamin C, fiber, folate,antioxidants but very few calories and sugar To encourage us to eat oranges daily tonourish the body

According to M.D Nguyen Thi Hang (Vice Chairman of the Department ofEastern Medicine, Vietnam Academy of Traditional Medicine): Orange juice containsflavonoids that are beneficial to health and is a source of hesperidin antioxidants.Orange juice is rich in vitamin C that can help lower blood pressure, the nutrients inorange juice also act as a diuretic, causing the kidneys to excrete more salt and waterout of the body to enhance resistance, anti-fatigue [31]

Drinking orange juice with a little salt added after exercising a lot of sweat is away to regain fitness quickly By the amount of fructose and 85% of the water in theorange will quickly be absorbed by the body, have a refreshing effect, and strengthenthe body [34]

Enhance eyesight: Orange is rich in carotenoids and vitamin A These substanceshelp enhance eyesight, especially good for women who have problems with maculardegeneration [34]

Anti-cancer: Scientists have recently published the results of the prevent-cancereffects of orange juice It contains flavonoid substances like hesperidin and naringenin

Laboratory studies have shown that orange juice reduces childhood leukemia, as well

as combating breast, liver, and colon cancers [31]

Reducing the risk of cardiovascular disease: Studies have shown that orange juicecan help reduce the risk of heart disease because it can help improve blood circulation[34]

Anti-aging for the skin: Oranges are full of beta-carotene which is a powerfulantioxidant that protects cells from damage, while also protecting the skin from freeradicals and preventing the signs of aging [34]

Weight-loss support: A large orange contains 4 grams of fiber and only 87calories Therefore, eating oranges helps you to prevent hunger, limit junk food habits

In addition, oranges are also rich in mineral vitamins to help you always feel healthy,full of energy [31]

Preventing virus infection: Consuming foods rich in polyphenols can help youboost your immune system, thus helping to protect you from viral infections Orangescontain lots of polyphenols which is an anti-viral, anti-inflammatory, anti-allergic,anti-carcinogenic and anti-proliferative agent.dustry to people and the economy [34]

2.2.2 The importance of the orange industry to people and the economy

Orange trees prefer tropical climates, strong vitality to easy to cultivate, and carecompared to many varieties Currently, the popular varieties of oranges such asgourmet oranges, oranges, etc give a high income to farmers If more techniques tohandle off-season flowering are applied to citrus, the selling price will be higher,which will bring a significant source of income for farmers

The domestic and foreign consumption markets are being expanded, thus creatingjobs and increasing incomes, improving economic life for farmers, and increasingexport turnover, creating a large revenue source It is estimated that with 1.5 ha ofland, it is possible to yield over 80 tons/crop

Orange trees have gradually asserted their effectiveness in the economicdevelopment of farmers For this model to bring about sustainable efficiency, thefunctional sector needs to create favorable conditions for farmers to access techniques,find quality seed sources as well as a stable consumption market so that gardeners canrest assured production

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2.3 The situation of orange production and consumption in Vietnam and worldwide

2.3.1 The situation of orange production and consumption in Vietnam

Figure 2.6 Area planted oranges in Vietnam from 2005 to 2018

Based on the chart, we can see that the area of oranges growing from 2013 to

2018 tends to increase, from 75 thousand hectares to more than 120 thousand hectares

in 5 years, which means that Vietnam is gradually investing in growing oranges, bringshigh productivity, contributing to the development of the economy

Figure 2.7 Orange production in Vietnam

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Production

(metric 601.3 654.7 678.6 693.5 728.6 702.7 704.1 706.0 758.9 727.4 806.9 957.9 1.055 thousand tons)

2016, an increase of 151 thousand tons [35]

Cao Phong District, Hoa Binh Province is one of the places with the largestorange supply in the North of Vietnam According to statistics February 2017, thewhole district has 2,080 hectares of citrus fruit In which oranges account for 1,367ha.The area of oranges in the business period is over 900ha, the harvested output in 2016

is over 23 million tons, the average price from 25,000 to 35,000 VND / kg This is agreat source of income for farmers in Cao Phong district Each year, Cao Phong orangeharvest season usually takes place from August to May of the following year, dividedinto varieties of early maturity, main crop and late ripening [35]

Sanh orange is planned on an area of over 7,000 hectares in 13 communes andtowns with over 4,000 households growing oranges; The average annual production isfrom 80 to 100 thousand tons, the price ranges from 40,000 to 50,000 VND / kg, theannual value is estimated at over 650 billion VND In 2007, Sanh orange was granted acertificate of product branding and trademark building by the National Office ofIntellectual Property It is in the "Top 50 famous Vietnamese specialty fruits", "top 10famous brands in Vietnam", and the title of "Vietnam Agricultural Gold Brand" [35].Vinh orange is planted in the key orange region of Nghe An in Quy Hop withover 2,000 hectares Average productivity is 27 tons/ha, there are outstanding areaswith productivity of over 45 tons/ha/year Each hectare of orange gives growers over

700 million VND [35]

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In Vietnam, products are processed from Orange specialties according to theprocess of ensuring food hygiene and safety Good oranges are utilized from the skin

to the intestines, so avoiding waste in the garden, taking advantage of oranges types 3and 4, creating additional income for orange growers Products made from orangeshave very good health effects such as orange peel jam, orange syrup for coughs, colds,orange essential oil for the steam bath to bring mental refreshment, treat fever, runnynose, beauty skin, can also be used in the processing of baked goods Products such

as orange wine, essential oil, orange jam, etc have enhanced the value of Vietnameseorange brand [35]

2.3.2 The situation of orange production and consumption worldwide

Figure 2.8 Orange production worldwide from 2012/2013 to 2018/2019 (in million

metric tons) (M Shahbandeh, 2019).

The chart shows the number of oranges produced worldwide from 2012 to 2019.The amount of oranges has changed markedly, as follows: in 2012/2013 was 49.85million metric tons, in 2018/2019 increased significant was 54.28 million metric tons

of oranges

Figure 2.9 Leading orange producing countries worldwide in 2018/2019 (in million

metric tons) (M Shahbandeh, 2019).

During the marketing year 2018/2019, we can see that Brazil is the largestproducer of oranges in the world, reached 20.16 million metric tons, according to thefigure 2.1, that year, the worldwide produced 54.28 million metric tons, therefore,Brazil account for about 37% of oranges production worldwide [36]

Following by Food and Agriculture Organization of the United Nations,Statistical Bulletin, 2016; production of oranges of all countries in the world from

2008 to 2016, in the Northern Hemisphere, countries with a large production oforanges such as the USA, Mediterranean Region included Italy, Spain, Egypt, Turkey,Mexico, China, India, Indonesia, Islamic Republic of Iran, Pakistan, in the SouthernHemisphere have Brazil, South Africa [22], [36]

2.4 Products made from oranges

Orange juice: It has bright colors and a refreshing flavor extracted from freshoranges and concentrated fresh orange juice and pasteurized to further retard spoilage

We can use orange juice to adds to drinks, candies and sweets

Orange peel extract is elaborated with orange peel and orange core The product

is the perfect options for beverages, soft drinks, or food applications

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Dry orange juice powder, this substance can be used within numerous products Ahandful of examples here can include Ready-made meals, jams, and syrups, flavorings,orange-flavored tea, as an additional ingredient within cookies, icings, and cakes.

Orange syrup: Its main uses are soft drinks and beverages, but it can also utilize

in the elaboration of ice creams, dairy products, bakery products, ready meals, jams,other syrups, etc Orange syrup with a brix level of 41.0-44.0

Orange Essential Oil is completely natural and is obtained from the peel of fruits

of different types of Citrus Sinensis obtain this product through a mechanical process,using a cold-pressed method and without any thermal treatments And then pack it indrums just after its extraction to maintain its properties

Jam products:

Fruit jams are products made from fresh or semi-prepared fruits cooked withsugar to dryness of 65-70% Featured jam products are sweet, naturally pure aroma ofberries In addition to the content of sugar available in the fruit, people also add a largeamount of sugar Fruit jam with high acid content also inhibits the activity ofmicroorganisms Most fruit jams need a certain amount of coagulation The coagulantavailable in the fruit is pectin During storage, jam can be gradually mortar, at first onthe face, and then spread out If stored at low temperatures, the product has a pH below2.8 and has many impurities, or is subject to mechanical impact, the jam becomes evenmore decompose [13]

Jam classification: according to the state of product structure

content is about 70-75%

· Crispy drying jam:

The product "candied orange slice" like Crispy drying jam, with pieces orangeconnect with sugar and dry at high temperature and create to the product with the drymatter around 90%

2.5 General process of producing candied orange slices

Fresh orangesWashingHandling

Soaking in limewater

Mixing withsugarConcentrationDryingCoolingPackaging

Product

Flow chart 1 General process of producing candied orange slices

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According to the research “Research on greening disease prevention and trialplanting of new orange varieties in Ham Yen, Tuyen Quang province, Viet Nam”, wehave the general procedure to producing our product Explain the procedure as follows[7], [27], [24]:

2.5.1 Fresh oranges

Raw materials used to produce products must be of good quality, achievematurity, a state of hardness and no defects, no smashing, meeting the standards ofTCVN 1873: 2014

2.5.4 Soaking in lime water

Soaking in lime water helps to increase the firmness of the product and removessome of the bitter substance in the orange peel

Procedure:

2.5.5 Mixing with sugar

The effect of sugar added to the product to create a sweet taste, increase the shelf life

Orange peels have the effect of increasing the flavor and freezing of the product.However, it is necessary to treat orange peel before mixing to reduce the bitterness ofthe skin, affecting the quality of candied orange slices

Soaking the sugar will help the orange pieces to soak into the sugar, while the melted sugar will avoid localized burning when concentrated

Procedure:

and dissolve

Procedure: The drying stage is used by specialized dry ovens

over natural cooling which is faster cooling time, the product is less changed

Fully print product information on the package including product name, netweight, ingredients, production date, expiry date, instructions for use, address of themanufacturer, etc.

(glass and plastic vials)

2.5.10 Preserving candied orange slices

Although products are high in sugar, the storage process does not guarantee water

to extend the shelf life of the product On a small scale, the product can be stored in therefrigerator