preliminary research on some technological specifications in the production of chocolate coated by orange peels

INTRODUCTION

Research rationale

Vietnam is a country located in the humid tropics, so tropical fruit trees are diverse and abundant, in which oranges are a very popular fruit tree, grown throughout all regions of our country, available all year round delicious fruit, high nutritional value but cheap price, especially with many health effects such as clearing heat, detoxifying, except cough, so it is very popular

Oranges can take advantage of all parts: leaves, flowers, peels, and fruits contain essential oils, used to prepare aromatherapy; orange seeds contain a lot of pectin, which can replace chemical pectin in food processing, in the production of medicines; Orange juice contains many nutrients such as fruit sugars, beta- carotene, vitamin C and minerals Phosphorus, Iron Currently, in addition to the orange peel is used mainly in the form of fresh eating, squeezing for fresh drinking water, most of the remaining parts are considered redundant and wasted

Recently, in folklore, there are also people who use orange peels to fresh or dry to cook drinking water that has the effect of sputum, easy to digest but not much, and there is still a very large amount of orange peel that has not been used

With the desire to take advantage of the abundant source of raw materials from orange peels, which can be obtained easily and very cheaply; creating jam products with novel flavors to diversify food products The study was carried out at the laboratory scale based on the basic in preparation of products for the purpose of building the product "Jam shell"; organize product quality assessment to start receiving feedback on products, as a basis for perfecting the production process and applying it to actual production

Besides, Chocolate is a product with high sensory and nutritional value, it is not used for semi-finished products for other candies but also provides us with a large amount of energy Not only that, it's one of those multi-functional, multi-use ingredients, whether it's dark black, milky or white In particular, Chocolate is also a very good product for health such as helping to reduce muscle blood pressure, lower blood pressure, reduce the risk of death, fight fatigue, etc And today it is also used in the field of health operations

From the above reasons, with the consent of the Department of Processing Technology Faculty of Food Technology - Thai Nguyen University of Agriculture and Forestry, we carried out the topic: " FIRST STEP RESEARCH ON SOME TECHNOLOGICAL SPECIFICATIONS IN THE PRODUCTION OF ORANGE PEELS JAM CHOCOLATE ”.

Theoretical foundations of basic processes

1.2.1 Selection and classification of ingredients 1.2.1.1 General

Selection is to remove ingredients that are not qualified for processing such as pests, rot disease, inadequate size and shape, inappropriate color

Classification: to divide raw materials into parts with similar properties, having the same size, shape, color, weight to have an appropriate processing mode for each type and help the finished product to have a good product the substance is uniform

Selection is carried out immediately after receiving when entering the processing place: washing, transporting, cutting, putting the product in the packaging

The classification and selection are usually done by manual method But with the manual method, it takes a lot of effort, and due to the continuous working hours and stressful activities, workers get tired quickly, which often negatively affects the quality of classification It is, therefore, possible to mechanize the selection of grades, based on differences in color, size, and density of the material

After selecting the classification, the raw materials are put through the washing stage At this stage of rinsing, the aim is to eliminate impurities, dust, and sand around the raw materials, and at the same time reduce a large number of microorganisms in the raw materials

Requirements for raw materials after washing: Must be clean, not crushed, with little loss of nutrients (when rinsing, avoid long exposure of ingredients to water)

1.2.2.2 Standards of water used in the food industry

Washing water as well as water used during processing (such as blanching, preparation) must be water used for food, ensuring the criteria as prescribed Water must be clear, colorless, and tasteless

During processing, a variety of materials are subjected to heat treatment during mechanical pre-processing, as well as prior to packaging People dip raw materials into water or solution, or process materials with steam, depending on the nature of the raw materials and processing requirements, at a temperature of 75 - 1000C, for 3-15 minutes

Factors affecting the blanching time: in the blanching process, in addition to inactivating the enzyme, it is also necessary to ensure product quality, so the food must be heated quickly Therefore, choosing the right temperature and time for each material is very important, and the heating time depends on the following factors:

• Heating method After blanching and steaming, it should be cooled quickly

Steaming has less nutrient loss than blanching, but in practice, people often blanch because of its convenient operation, simple equipment, and better heat transfer when steaming

Expel the gas present in the material's intercellular space In order to limit the effect of oxygen occurring in the box, avoid bulging the box, corroding the iron box, oxidizing vitamins Blanching also reduces substances with inappropriate flavors such as bitter taste (bamboo shoots, eggplant) sulfur compounds (vegetables, cabbage, poultry)

Make vegetables lighter in color by destroying some colorants When blanching in a solution of citric acid or NaHSO3 these substances will destroy some color compounds, making the material lighter in color

Reduces the amount of microorganisms attached to the surface of the material

Although processing at not very high temperature, with not a long time, it is possible but can kill some less heat-resistant microorganisms on the surface of the material.

Sugar osmosis

Osmosis is the phenomenon where once a concentration difference (or more precisely a concentration difference (or more precisely, a difference in the chemical activity of the solvent) causes the solvent (water) to penetrates a membrane that is more permeable to the solvent than to the solute, which is called a semi-permeable membrane

Osmosis is a special case of diffusion It is diffusion across a semi-permeable membrane where water can pass through the membrane and other solutes cannot

Osmosis is the movement of water across a semi-permeable membrane from the side of higher concentration

When two solutions of different solute concentrations are separated by a semi-permeable membrane separated by a semi-permeable membrane, water from the dilute solution will cross the semi-permeable membrane permeate a more

Water migration will stop when the concentrations of the two solutions are equal The volume of the dilute solution will decrease and the volume of the concentrated solution will increase after the process is terminated

Figure: Permeation of water across the cell membrane

Research’s objectives

Initially, research on some technological parameters in the production of chocolate covered with orange peel jelly, make use and solving problems of a large amount of orange peel by-products during the orange peel intestines

1.4.2 Specific objectives a, Research to optimize the factors affecting the production process from orange peel jam

- Survey on drying temperature of orange peel jam - Survey on drying time of orange peel jam

- Determining the appropriate ceiling time of raw materials for orange peel jelly products

- Research on the effects of the bitter elimination method on product quality

- Research on the ratio of mixing orange and sugar on product quality b, Research to optimize the factors affecting the chocolate production process - Determine chocolate cooking time

- Determine the chocolate cooking temperature - Determination of chocolate cooling time c, Evaluation of sensory quality of finished jams made from orange peels

Meaning of the research

- The theme encourages students to participate in scientific research in the field of food processing

- Understand and grasp the knowledge learned - Supplementing knowledge through practical research activities, cultivating personal knowledge, accumulating practical experience, and at the same time approaching scientific research for future research and work

- Help students consolidate and systematize learned knowledge into scientific research

- Help students have more practical working skills after graduation in terms of observation, processing, product evaluation, quality management

- Creating dried marmalade products with good quality in terms of sensory and health, creating trust for consumers

LITERATURE REVIEW

Overview of orange peel, chocolate

2.1.1 Orange peel overview 2.1.2 Features of orange peel

Orange is a fruit that provides many nutrients beneficial to health In addition, processing by-products from orange peels also provides a rich source of phenolic compounds and dietary fiber, due to the large amount of peel produced Orange peels are often discarded as waste in the environment This is considered a potential product source due to its low cost, availability and environmental friendly nutritional products

Orange peel is thick, white, has a slightly bitter taste, is moist, and in fact, orange peel has many uses, prevents many diseases, and is very good for health

There are so many benefits that orange peels bring, which is why you should never throw away orange peels Orange peel contains more nutrients than the inside

100g of orange peel contains 135mg of vitamin C but the same amount of orange pulp, it only contains up to 70mg of vitamin C For obese people, orange peel is extremely good and has the effect of reducing blood pressure Orange peels contain a substance called hesperidin, which is an antioxidant It is said that this substance has a very good effect on lowering blood pressure, lowering cholesterol, and anti- inflammatory Orange peel has a very good effect in regulating metabolism and is beneficial for the digestive system They are also great for weight loss Orange peels contain flavonoids, which are thought to inhibit certain proteins linked to cancer and obesity Therefore, it is necessary to take advantage of the health benefit of orange peel Orange peel is also rich in magnesium, calcium, fiber, and vitamins

B and C, which are extremely good for the body Orange peel is very effective in fighting allergies, it also cleans the lungs because it can clear the phlegm in the throat when eating orange peels In addition, orange peel helps to whiten the roast and reduce bad breath

Besides, the antioxidant vitamin C can strengthen the connection between tissues and prevent nasal congestion This nutrient is also essential for the production of peptide hormones, tyrosine, dopamine, and ATP The body also needs to use vitamin C to absorb and process other nutrients such as iron and calcium Along with iron and calcium, vitamin C can help the body fight harmful lead toxins Vitamin C also contributes to healthy bones, tendons, and skin

Vitamin C can also neutralize antioxidants, reduce the risk of cancer and many other diseases Not stopping here, this vitamin also plays an essential role in strengthening the immune system, helping the body eliminate free radicals and harmful impurities Therefore, this is also considered as one of the criteria to evaluate the effectiveness of methods of processing and preserving vegetables

2.1.3 The chemical composition and nutritional value of orange peel Pectin:

As the mucus that surrounds the seed coat and pulp of an orange, it is a type of fiber, soluble in water and increasing viscosity Fresh orange peel contains 1- 2% pectin, but when dried, the pectin content in the peel decreases to 0.5-1%

Pharmacological effects of pectin: fat loss, lipid absorption, reduction of total blood cholesterol in dyslipidemia patients At the same time, control hyperglycemia before and after meals in people with diabetes

It is a non-sugar polysaccharide, a major component of plant cells It is insoluble in water, humans cannot digest Cellulose because there is no enzyme needed to break it down However, some bacteria are capable of breaking them down into CO and H O

Pharmacological effects of Cellulose: prevention of colon cancer, prevention of atherosclerosis, reduction of gallstone formation, reduction of blood fat, and prevention of obesity

C28H34O5, abundant in the rind of Citrus, has a bitter taste, has Vitamin P activity, plays a role in permeability and elasticity of blood vessel walls When hydrolyzed, Hesperidin will hydrolyze to ramnoza and aglucon hesperidin

C27H32O14, in white peel and citrus fruit, is the substance that causes the bitter taste

Nutritional Value Of Orange Peel

Most of us remove the peel when we eat oranges, but what many of us don't know is that this peel is very nutritious and has many miraculous benefits for our health Orange peel contains more than 60 types of Flavonoids and more than 170 types of phytonutrients, in addition to being rich in pectins, vitamins, minerals, and fiber

Table 2.1 Nutritional table of orange peel (According to USDA - USA)

The situation of orange production and consumption in Vietnam and worldwide

2.2.1 The situation of orange production and consumption in Vietnam

Figure 2.2 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, brings high productivity, contributing to the development of the economy

Figure 2.3 Orange production in Vietnam Although the area of oranges planted from 2005 to 2013 decreased, the production of oranges still tended to increase and stabilize, this means that the production of oranges / area increased, thus, the area of orange planted has been significantly expanded since 2013 In 2016, orange production increased to 10.9% compared to 2015, orange production in 2017 increased by 18.7% compared to 2016, an increase of 151 thousand tons

Cao Phong District, Hoa Binh Province is one of the places with the largest orange supply in the North of Vietnam According to statistics February 2017, the whole 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 a great source of income for farmers in Cao Phong district Each year, Cao Phong orange harvest season usually takes place from August to May of the following year, divided into varieties of early maturity, main crop and late

In Vietnam, products are processed from Orange specialties according to the process 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 3 and 4, creating additional income for orange growers Products made from oranges have 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, runny nose, 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 Vietnamese orange brand

2.2.2 The situation of orange production and consumption world

Figure 2.4 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 49.85 million metric tons, in 2018/2019 increased significant was 54.28 million metric tons of oranges

Figure 2.5 Leading orange producing countries worldwide in 2018/2019

Socola

2.3.1 History of formation and development

The history of the origin of the cacao tree: the cocoa tree appeared more than 3000 years ago and was first developed in Mexico Over time, Native American tribes such as the Mayans and Aztecs realized that the beans of the cacao tree could make a delicious drink The Aztecs called it xocolatl (zo-ko-lah-tl) The Mayans believed that the cocoa tree belonged to God and that the cocoa bean was God's grace to man The Mayans were probably the first people on this earth to use chocolate as food At first, Chocolate was not sweet, but spicy Unsweetened chocolate has a bitter taste

The presence of chocolate in European countries became a luxury: in the 1600s, chocolate spread throughout Europe and soon became a popular drink Between 1500 and 1800, rich people in Europe found a new way to make chocolate less bitter, they added cinnamon, some began to sweeten them with sugar

The age of the first chocolate bar: in the 19th century, solid chocolate became popular, with the introduction of molds People use a grinder to grind cocoa beans into a fine powder, then heat it and pour it into a mold, creating different shapes when cooled A Dutchman named Coenraad Van Houten perfected the extraction of cocoa butter from cocoa beans in 1825 The beans were crushed into a paste, heated under high pressure, creating a chocolate liquid and cocoa butter This extracted butter is smoothed and treated to deodorize By 1880, Rodolphe Lindt of Switzerland added cocoa butter to the chocolate production process, to make the product smoother and shinier Cocoa butter melts at 36ᵒC, human body temperature That's why chocolate melts in your mouth

Chocolate is not only known as a food rich in energy, is one of the most popular flavors in the world, but it can also be used for many different purposes:

Used to prepare drinks, decorate dishes, drinks

Adding to foods not only increases nutritional value, creates unique delicious flavors, and also attracts consumers

As raw materials for the production of food products such as candy, cake, ice cream, etc

For health: especially dark chocolate, has antioxidant effects, good for circulation, reduces the risk of stroke, lowers cholesterol, prevents diabetes, improves memory, creates a feeling of euphoria, stimulates,…

Chocolate is a food made from the fruit of the cocoa tree Chocolate is a mixture of cocoa powder and cocoa butter, to which sugar, milk, and other ingredients are added

Chocolate has two main forms of finished products: solid and liquid

Table 2.2 Chemical composition of chocolates

Chocolate recipe Typical percentage of ingredients in

(Cocoa Powder and Cocoa Butter) 11.8 39.6 60.7

Flavoring Compounds (Salt and vani)

There are many ways to classify chocolate products One can classify chocolate according to the purpose of use, by chocolate product, by ingredient, or by raw material for making chocolate In which classification by production materials is the most common, chocolate is divided into the following types:

Dark Chocolate: Chocolate without milk The main ingredients of Dark Chocolate are cocoa powder, cocoa butter, sugar, and vanilla In which cocoa powder accounts for about 35% by volume

Milk chocolate: similar to dark chocolate, but mixed with milk powder or condensed milk to create aroma, sweetness and nutritional value In which cocoa powder accounted for 25% by volume White chocolate: main ingredients include cocoa butter, sugar, vanilla and milk Because it is made mainly from cocoa butter without cocoa powder, white chocolate does not have a pronounced chocolate flavor but has flavors of vanilla and milk In which cocoa butter accounts for at least 20% by weight

Mixed chocolate: is a technical word for chocolate that does not use cocoa butter, but uses vegetable fat instead Its main ingredients include: cocoa powder, vegetable fat, sugar and food additives In which cocoa powder accounts for at least 35% by weight

2.3.5 Research status of chocolate products in the world and in Vietnam

The largest cocoa bean production in the world is in Ivory Coast and Ghana (in West Africa), amounting to 1476 thousand tons in 2012

Confectionery products made from cocoa beans have the highest production in the United States, with sales of about 17 billion US dollars

The highest chocolate consumption is in European countries, the highest is in Switzerland with 8.89kg/person/year In Vietnam

According to the assessment of the Vietnam Cocoa Coordination Board (under the Ministry of Agriculture and Rural Development), the current demand for chocolate in Vietnam is about 5,500 tons/year, but most of it is imported chocolate

In Vietnam, there is not a single chocolate production industry like many other countries in the world, but it is mainly produced by confectionery businesses

But at present, many businesses have not promoted investment in chocolate production and the production process has not paid attention to using domestic cocoa raw materials In the market, there are only a few large enterprises with chocolate products such as Kinh Do, Bibica, Hai Chau However, Vietnamese chocolate products are only considered as a common confectionery product, with packaging and design , even the quality is not different from ordinary confectionery and of course is not built into a brand

According to the latest survey results of market research company Kantar Worldpanel, in the first 6 months of 2014, chocolate is a commodity with a double growth in consumption volume compared to the same period in 2013 in the Vietnam market

Accordingly, the chocolate industry has attracted 52,000 new consumers and increased the average chocolate consumption per household by 24% As for consumers in rural areas, chocolate-flavored drinks (milk, cereals ) also increased impressively by 47% and an additional 675,000 people chose to buy chocolate products.

Research Methods

2.4.1 Investigate factors in the research process

To produce the product "Orange Peel Jam" with a harmonious structure, color and taste, the following factors were studied:

 Investigate the influence of pickling solution, concentration of

 Effect of blanching time on bitter taste of orange peel

 Investigating the ratio of orange peel: sugar, cooking time of orange peel in sugar affects the structure, color and taste of the product

2.4.2 Sensory evaluation and product quality

Survey of consumer preferences for products to see how successful the entire research process is For food, the sensory method has become the official method, indispensable in assessing product quality because it is a scientific method used to evoke, measure, analyze and interpret assessors' responses to the inherent organoleptic properties of a food product (color, form, taste, and texture), assessing product quality based on the use of information obtained by receptors such as sight, touch, hearing, smell, and taste A food product with very good nutritional criteria but unusual appearance and taste will hardly be accepted by consumers Therefore, people also use the concept of sensory labeling which is the analysis of common organoleptic properties based not only on the inherent properties of food, but also on the level of preference of the tester for that product or that property There are many types of sensory methods, of which the most commonly used method is the method of taste perception

Surveys must be performed on a wide variety of users

Make a taste survey questionnaire for four sensory criteria of the product: color, texture, and taste

Because there was no training time, only ten students of food technology were selected for sensory evaluation

 Processing results: The score for each sample is the position that the tester has arranged for them We sum by column, the sample with the smallest column total is the highest rated sample

Based on the distance between the smallest sum and the largest sum If these two values are far apart, the difference is more significant Look up the Appendix table of 8 books on Food Sensory Analysis Techniques by teacher Ha Duyen Tu

Give us the critical values at the significance level α = 5% corresponding to 10 testers and 3 samples of 15 – 25 and 16 – 24

Sensory analysis method is specified in Vietnamese standard “TCVN 3215- 79_ Food products _ Sensory analysis _ Scoring method” In the scoring method, many scoring systems can be used, many levels and in each level there can be different grading scales Vietnamese standards use a 20-point system to build a unified 6-point scale of 5 points (0 to 5) and score 5 is the highest score for the evaluation indicator

This is a dried jam product, so the structure and color criteria often affect the initial choice of consumers Therefore, choose the important coefficients of the indicators as:

- The important coefficient of structural criteria is: 1.2 - The important factor of color index is: 0.8

- The important coefficient of the taste index is: 1.0

The number of people participating in the analysis and evaluation is 10 people The criteria depending on the level of performance are scored as follows:

Targets Important factor Request Point

Characteristic yellow-orange color of the product

Discoloration (brown) Discoloration due to product damage

The sweetness is not harmonious

The taste of the product is damaged

Has a characteristic aroma of orange peel

Little smell of orange peel

No smell of orange peel

Calculate the average of the members for each sensory criterion, to the nearest one decimal place Then multiply by the respective importance coefficient of each indicator

Calculate the total weighted score of all sensory indicators Then classify the product quality based on that average score according to the quality level specified in TCVN

The product is qualified when the weighted average score of any criterion must be at least 2.8 and the quality score is not less than 11.2 If the council agrees for a certain criterion 0, the common score is 0 and the product is considered defective If any member deviates more than 1.5 points from the unweighted average of

Score cards are as follows:

Sensory Analysis Lab Score card Test for Quality Score (TCVN 3215-79)

Product: Orange peel jam Answer:

Each member gets 1 scorecard and scores on each vote Process the scoreboard given by the members, giving the final result what quality the product belongs to.

Overview of jam products

Orange juice: It has bright colors and a refreshing flavor extracted from fresh oranges 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 perfect options for beverages, soft drinks, or food applications

Dry orange juice powder, this substance can be used within numerous products A handful 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 in drums just after its extraction to maintain its properties

Fruit jams are products made from fresh or semi-prepared fruits cooked with sugar to dryness of 65-70% Featured jam products are sweet, naturally pure aroma of berries In addition to the content of sugar available in the fruit, people also add a large amount of sugar Fruit jam with high acid content also inhibits the activity of microorganisms Most fruit jams need a certain amount of coagulation The coagulant available in the fruit is pectin During storage, jam can be gradually mortar, at first on the face, and then spread out If stored at low temperatures, the product has a pH below 2.8 and has many impurities, or is subject to mechanical impact, the jam becomes even more decompose

Jam classification: according to the state of product structure

- Processing from juice or fruit pure

- Create gel coagulated with pectin or agar

- There are 3 types: Jelly, Jam, Marmalade

- The dry matter content is about 60-65%

- Pieces or whole fruit - Soft, slightly wet, no more sugar syrup around the product

- The dry matter content is about 70-75%

- Outside there is a sugar coat crust

2.5.2 General process of producing orange peel

Diagram 2 General process of producing orange peel

2.5.3 Explain the procedure as follows 2.5.3.1 Fresh oranges

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

The fruits after selection and classification are washed to remove all impurities and microorganisms adhering to the crust

After washing, cut off the stem, the fruit is cut into thin slices, remove seed, remove broken orange, and unsatisfactory orange piece to prepare for the next step

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

- Put the orange pieces into the prepared lime water and soak for 10 hours - Rinse with clean water after soaking

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 of the skin, affecting the quality of candied orange slices

Soaking the sugar will help the orange pieces to soak into the sugar, while the

- Put sugar into orange after draining

- After mixing sugar, let stand for 12 hours for the orange to soak into the sugar and dissolve

- Concentrate orange slices on low heat to avoid burning the product due to caramelized

- During the concentration process, stir well and do gently to avoid broken orange pieces

- Orange pieces after concentration will be uniform yellow, dry sugar will stick around

The drying process of product works to lose some of the water in the product, the product is drier, flexible, does not drain, and preserves longer

Procedure: The drying stage is used by specialized dry ovens - Set the drying temperature

- Spread the orange pieces after concentrating on the drying tray - Put the drying tray into the oven

Purpose: To continue releasing the remaining steam in the product, and to lower the temperature of the product, helping to prevent water when packaging

Procedure: After drying, remove the tray from the oven Cooling the product in two ways is natural cooling and forced cooling:

+ Natural cooling: A method to cool after drying in the room and slowly + Forced cooling: As a fan-cooling method, this cooling method has advantages over the natural cooling which is faster cooling time, product is less changed

Purpose: To help the product is isolated from the outside environment, prolong the time of storage and use of the product

+ Prepare packaging: Can use PE bags or glass jars, plastic jars to contain products.

About jam

Jam, fruit jam, or fruit jam can be found in many countries around the world, it is made from some fruits and some tubers cooked with sugar to 65-70% dry

Sugar ingredients in jam are always present and need to reach a concentration of 55-60%, it not only plays the role of sweetening but also has the effect of preserving jam and increasing freezing In jam, microorganisms are shrinking protoplasm so they are inactive, or do not grow because of the high acidity (in jam), so there are many types of cooked jam that do not need to be pasteurized (however there are some jams) jams with lower dryness need to be pasteurized for a short time to kill yeast and mold) Jam is processed into many forms, which can be classified into the following types: frozen jam, puree, frozen jam, flexible jam, and dried jam

Requirements of chocolate orange peel jam products

Color: brown of chocolate coating, not contaminated with other colors

Taste: sweet-slightly bitter of chocolate, the characteristic sweetness of orange peel jam, not mixed with other flavors

Structure: the outer layer is slightly crispy of chocolate, flexible and slightly chewy of a piece of marmalade

CONTENTS AND METHODS

Object and scope of the study

Orange peels from Cao Phong oranges from Hoa Binh Cao Phong oranges are purchased at Cao Phong-Hoa Binh with prices ranging from 18,000-19,000 VND/ 1kg

The purchased oranges are washed, scrubbed through the outer skin, then cut in half, squeezed to get the juice and removed from the intestines inside Wash again, dry, and cut into pieces

Research location

Major food technology, Thai Nguyen University of Agriculture and Forestry

Research time

Resarch instruments, equipment, tools, chemicals

Water Bath Drying Oven Precision Balance Viscometer Desiccator Hardness Testing Machines Spectrometers Uv Vis Fridge

The scissors, basin, colander, knife, chopping board 50ml, 100ml volumetric flasks; pipette 1ml, 2ml; Measuring cylinder, Erlenmeyer Flask, filter paper, Funnel

3.4.4 Research content a, Research to optimize the factors affecting the production process from orange peel jam

- Investigate the drying temperature of orange peel jam - Survey on drying time of orange peel jam

- Determine the appropriate ceiling time of raw materials for orange peel jam products b, Research to optimize the factors affecting the chocolate production process - Determine the chocolate cooking time

- Determine the chocolate cooking temperature - Determine the chocolate cooling time c, Evaluation of sensory quality of finished products made from orange peels

3.5 Proposed technological process for the production of chocolate covered with orange peel jam

Diagram 3 Technological process for the production of chocolate covered with orange peel jam

3.5.2 Process explanation 3.5.2.1 Explain the procedure

Mix the ingredients: cocoa powder, cocoa butter, sugar, milk, together in a certain ratio to form a homogeneous liquid for use in the next process b The changes that occur in the process

Physical: in the process of mixing, the temperature of the mixture increases,

Physicochemical: from the initial mixture, through the stirring process, it becomes a homogeneous suspension, with cocoa butter as the continuous phase, and sugar, milk and cocoa powder as the dispersed phase c Implementation method and specifications:

The chocolate mixture, after mixing with many particles of different sizes, will be put into a fine grinding device to grind the powder to a size of about 30 ɱm, creating a very smooth, highly uniform mixture The temperature of the mixture in the device is always around 45-48ºC

Cook the mixture after grinding finely, creating a unique texture and flavor for chocolate b The changes that occur in the process:

Physics: The temperature of the chocolate mass increases due to the friction between it and the wall of the device and between the chocolate molecules, the viscosity decreases

Chemicals: Because this process occurs at high temperatures and over a long period of time, many reactions occur In particular, the Maillard reaction creates the characteristic color, odor and taste of the product Mixed moisture reduced Physicochemical:

Lecithin is added 1 hour before the end of the mixing process with the aim of: reducing viscosity, helping the chocolate block to achieve the required liquid; both improve chocolate structure and reduce the risk of "fat bloom" c Implementation method and specifications:

The process temperature is kept at 60-80ºC for chocolate without milk and 45-60ºC for chocolate with added milk The time lasts from 48-72 hours, depending on the type of chocolate and different equipment

Complete: stabilizes cocoa butter crystals from unstable to more stable, avoiding "sugar bloom" and "fat bloom" In addition, it also helps the cocoa butter crystals to be evenly distributed so that the chocolate can easily solidify during the cooling process

Preparation: after chocolate crystals form, raise the temperature to 32-330C, creating favorable conditions for pouring the mold b The changes that occur in the process

Physical: due to temperature change, complete crystallization of stable and unstable crystalline forms

Physicochemical: Cocoa butter has many crystalline forms and unstable forms will change to more stable.

Research methodology

3.6.1 Determining the suitable drying temperature for orange peel jam products

After cooking the jam, the jam will be put in a convection oven with three different temperatures for the same time and humidity as designed in Table 3.6

Table 3.1 Experimental design to determine the drying temperature of orange peel jam

The finished jam will be analyzed to determine moisture content, total dry matter content and sensory evaluation by scoring test

3.6.2 Determine the suitable drying time for orange peel jam products

Table 3.2 Determine the suitable drying time for orange peel jam products

+ Mass materials + Drying temperature: Choose from experiment

The finished jam will be analyzed to determine moisture content, total dry matter content and sensory evaluation by scoring test

3.6.3 Determine the chocolate cooking temperature to wrap the orange peel jam

Chocolate will be heated to different temperatures with the elements kept constant as shown in table 3.6.3 below:

Table 3.3 Experimental design to determine the chocolate cooking temperature

Formula Temperature (ᵒC) Fixed factors

After the chocolate is heated, it will be evaluated sensory by scoring test.

Analytical methods

3.7.1 Physical method 3.7.1.1 Determine the viscosity of Chocolate with a viscometer The principle

After finishing the chocolate cooking process, we need to test the viscosity of the mixture, in order to create a mixture that achieves an appropriate viscosity

After cooking, proceed to take 70ml of liquid chocolate mixture into the sample tube of the viscometer, measure the sample at 40ºC Turn on the meter, select the probe for low viscosity solution as S64, set the measuring time to 60 seconds, the measuring speed to 60 RPM, and then take the measurement

After the meter is finished, record the result in mPa.s and the confidence level (must be ≥10%)

3.7.1.2 Determination of hardness of chocolate orange peel jam with a hardness tester The principle

After finishing the cooling process of chocolate covered with orange peel jam, we need to conduct a hardness test of the product, in order to create a product that achieves an appropriate hardness to have a product with good quality

Hardness is determined exactly by the magnitude of the force required for the probe to penetrate of the sample thickness

Sample preparation, same sample size Samples were left at 60°C for 18 hours before being measured The probe must also be chilled to the same temperature to avoid affecting the sample

Probe Diameter: 3.12mm Cutting speed: 20cm/min

Read the measured results on the machine with the unit is Newton

3.7.1.3 Determine the melting rate of chocolate The principle

After completely freezing the chocolate block, we need to check the melting rate of the chocolate block, based on the temperature difference between the outside environment (with a higher temperature) and the chocolate block, where the butter crystals are melted cocoa, in order to choose the most optimal recipe for chocolate products

After the chocolate block is completely frozen (chilled for 2 hours), measure the initial mass of the sample Using a small plastic container the same size as the sample container, turn the two boxes upside down (the sample container is on top)

Put them in the oven at 350C to stabilize the temperature, measure the volume of chocolate flowing down the box once every 10 minutes

While: m1 is the initial mass of the chocolate block (g); m2 is the mass

3.7.2 Chemical Methods 3.7.2.1 Determine humidity The principle

Apply drying method to constant weight

We dry the clean weighing beaker in the drying oven at 105˚C to constant weight, use an analytical balance to weigh, determine the weight of the weighing cup (g), put the materials to be analyzed in the beaker, and weigh the stool volume, record the mass, then the sum of the beaker and sample is (g) Place the cup in the oven at 105˚C, dry for about 4 hours, then take it out and let it cool for 15 minutes in a desiccator with desiccant Weigh the dried sample cup After weighing, leave the beaker for about 2 hours, then weigh again until the mass between the sample cups between drying times does not change, record the mass (g)

While: : mass of sample and cup before drying

: mass of sample and beaker after drying to constant mass

3.7.2.2 Determination of total sugar content The principle

The method is based on coloration between reducing sugars and dinitrosalicylic acid (DNS) The color intensity of the reaction mixture is proportional to the concentration of reducing sugar in a certain range

Build a standard graph of glucose First phase the glucose standard sequence from 0; 0.2; 0.4; 0.6; 0.8; 1 (mg/ml) Add 1 ml of DNS reagent to the test tubes above, boil for 5 min, and then cool to room temperature Measure optical density at 540 nm with distilled water as a control Construct a standard curve describing the correlation between optical absorbance and glucose concentration

Prepare the test solution In order for the experimental solution to convert all sugars into reducing sugars, we add 5ml of HCl to hydrolyze at 70-80˚C for 30 minutes, then measure again with distilled water

Note: Carry out calibration and test samples at the same time

Based on the built-up standard curve, the total sugar content in the experiment will be determined, the result is the average of 3 replicates

3.7.2.3 Sensory evaluation of finished chocolate products wrapped with orange peel jam and compared with products on the market

Evaluation of sensory quality of orange peel chocolate products:

- Sensory method: Give the taste score according to the Hedonic scale - Sensory evaluation committee: 10 people

Panelist Hedonic Rating Linking Score

3.7.2.4 Analysis and evaluation of sensory quality of chocolate orange peel jam products

Person Color Structure Flavor Smell

Average scoreboard without weighting coefficients

Average scoreboard with weighting coefficient

Comment: From the results of sensory evaluation, we see that the product is liked by many people, and the structure and smell are highly appreciated

However, the taste of the product has not been harmonized (the taste of the product is slightly more bitter than expected), so it needs to be overcome by adjusting the amount of sugar.

Product price

- Ingredients (orange peel + sugar + salt) Product (1kg orange peel + 2kg sugar) (0.75 kg) - Orange peel bought at the store: 1200 VND / 1 kg

- Salt : 7000 VND/ 1kg Total cost (materials) = 1200 VND + 48000 VND + 420 VND (salt) = 49620 VND

RESEARCH RESULTS AND DISCUSSION

Survey results of orange peel and chocolate ingredients

Choose Cao Phong oranges to get orange peels Cao Phong is an area with gentle hilly terrain, mainly made up of feralit soil The climate here is very suitable for growing juicy and succulent orange trees Orange trees have long become a staple crop, helping people here "eliminate hunger and reduce poverty" Currently, there are more than 5,000 households growing orange trees in Cao Phong district

Each house planted at least a few hundred roots and sometimes up to several thousand roots After being granted a geographical indication certificate in 2014, more than 50% of oranges in this area met VietGAP standards This helps consumers have more confidence in the quality of each orange here

Oranges have fruit weight from 160g - 190g, fruit diameter from 7.49 - 8.34 cm, fruit height from 5.84 - 6.51 cm, oranges have a light aroma, sweet taste and sour but very sweet taste yummy Succulent orange shrimp, red yellow, multi- segment, suitable for squeezing juice or can be used directly after peeling Vitamin C content from 19.54 - 24.61 mg/100g of fruit juice, total organic acid from 0.63 - 0.78%, total sugar from 6.89 - 8.12%, Brix from 8 25 - 9.60 %, water content from 87.22 - 89.34 %.

Investigation of drying mode for orange peel jam

4.2.1 Survey results of drying temperature affect the quality of orange peel jam

In the production of chocolate orange peel jam, the drying stage is very important, directly affecting the sensory quality of the product But in this period we do not dry orange peel jam at the temperature to be investigated immediately, because according to the principle of drying, the temperature should not be too high, if the temperature is high, the outer surface of the marmalade will be dry hardens quickly, making the process of evaporation of water from the orange peel jam to the environment limited Thus, orange peel jam products after drying will have uneven moisture, reducing the storage time of the product later

4.2.1.1 Survey results on the influence of drying temperature on the moisture content of orange peel jam

Humidity has a great influence on the nutritional quality as well as the sensory quality of orange peel jam products

The effect of drying temperature on the moisture content of orange peel jam is shown in Figure 4.1

Figure 4.1 Effect of drying temperature on the moisture content of orange peel jam Through the data in Figure 4.1 we can see that when drying orange peels at different temperatures, the moisture content of the product will be different When increasing the drying temperature, the moisture content of the product decreases

Temperature(°С) gradually, the highest at 500C is 4.5%, the lowest at 900C is only 1.8% This decrease in moisture is because when the temperature increases, the rate of water evaporation will increase, the higher the temperature, the higher the rate of moisture evaporation and vice versa Moisture is a factor reflecting the brittleness of the product after drying The lower the humidity, the longer the product can be stored Therefore, to ensure better product quality after drying, it is necessary to choose the most suitable drying temperature for the product

4.2.1.2 Effect of drying temperature on total sugar content

Figure 4.2 Effect of drying temperature on total sugar content Looking at Figure 4.2 we see that the total sugar content is inversely proportional to the drying temperature When increasing the drying temperature, the total sugar content of the product gradually decreased, the highest at 50ºC was 74.90%, the lowest at 90ºC was only 71.90% This can be explained as follows: when the temperature is increased, the amount of sugar in the orange peel jam will be reduced gradually because caramelization and male reaction have occurred, so the sugar content will be partially reduced compared to the original amount Therefore, in production, sometimes people take advantage of caramelization and may lose

Temperature( ℃ ) reactions to give the product a beautiful yellow color

4.2.2 Survey results of drying time for orange peel jam quality

During the drying process of orange peel jam, drying temperature is also one of the important factors that directly affect the sensory quality of orange peel jam

We do not dry the product in the period that needs to be surveyed immediately but dry it for a short initial period first Therefore, the survey to find out the optimal drying time for orange peel jam plays an important role

4.4.2 Results of determining the effect of cooking time on the firmness of chocolate covered with orange peel jam

Similar to when changing the cooking temperature leads to a change in the hardness of chocolate when changing the cooking time, the hardness of the chocolate is different

The results of determining the effect of cooking temperature on chocolate hardness are shown in Figure 4.7

We have the following graph:

Figure 4.3 Effect of cooking time on chocolate hardness

From the data of Figure 4.7., we can see that the hardness of chocolate increases steadily when the cooking time increases from 7 to 11 minutes, the lowest at the cooking time is 3 minutes, the hardness is only 2.51 N When the temperature increases, the hardness of the mixture increases because when the temperature increases, the mixture gradually loses moisture, the mixture becomes dry At the cooking time of 5 minutes, the hardness index is the highest at 6.42 N, which can be explained by the fact that when cooked at this temperature, crystals are formed, creating a strong and stable structure Best As for the cooking time of 3 minutes, the hardness of chocolate is the lowest (2.51N), because, despite having a higher moisture content, the solute components are not evenly distributed, and an emulsion has not yet been formed Relative stability should have small stiffness

Therefore, we will choose the model with the highest hardness, with a cooking time of 5 minutes

4 2 3 Results of determining the effect of cooking time on the melting rate of chocolate

The effect of cooking time on the melting rate of chocolate has the same mechanism of action as the effect of cooking temperature on chocolate moisture

When the cooking times of the samples were different, their melting rates were also different

The results of determining the effect of cooking time on the chocolate melting rate are shown in Figure 4.8

We have the following graph:

Figure 4.4 Effect of cooking time on the chocolate melting rate Through the data in Figure 4.4.3, we can see that when cooking chocolate at different times, different melting rates will be obtained The rate of melting when changing the time at 3 minutes, 5 minutes has a big change, increasing steadily with the increase of cooking time The melting rate when changing the cooking time at the 5-minute, 7-minute mark also has a big change, decreasing evenly with the increase of time Melting rate when changing cooking time at 7 minutes, 9 minutes, 11 minutes also had a big change, increasing steadily with increasing time At the 5-minute time mark, the melting rate reached the highest value of 39.62%, explaining this as follows: because at the 5-minute time mark, this is an unstable time, making the particles The component crystals in the chocolate mixture have not been fully formed, so the chocolate mass has melted, and the melting rate is high Although at the time of 11 minutes, the melting rate also reached a fairly high value of 32.81%, in order to reduce costs and energy during the experiment, we decided to choose a cooking time of 5 minutes minutes for the

4.3 The results determine the optimal cooling time for chocolate

The cooling time has a great influence on the organoleptic properties as well as the quality of chocolate It directly affects the formation of fat crystals, giving structure to the product, the melting point of chocolate If the short cooling time leads to the fat crystals not having enough time to crystallize, forming stable crystals, and the structure is not uniform, the fat will recrystallize, causing “fat bloom” " If the cooling time is long, the structure of the chocolate will be too hard, affecting the taste Because of that, choosing a cooling time for chocolate is very important

4.4 Establish a process for processing product orange peel

Based on the above experiments, we propose the technology procedure for producing orange peel as shown in the below:

Diagram of the production process of orange peel (10kg fresh orange)

Diagram 4 Diagram of the production process of orange peel jam

4.4.2 Description the production process of orange peel jam Step 1: Preparation the ingredients

Figure 4.5 The main materials: orange and Sugar

The fruits after selection and classification are washed to remove all impurities and microorganisms adhering to the crust by clean water

Step 3: Cutting the orange into slices orange

- After washing, cut off the stalk, the fruit is cut across the citrus into thin slices (about 1cm to 1.5cm) from the stem to the bottom

- Getting all the seeds out

- Remove the pieces of orange torn, unsatisfactory

Figure 4.7 Cutting slices orange and remove the seed

Step 4: Soaking the slices orange in brine water

- Soak the orange pieces in 20 liters of 5% brine solution - Soaking time: 10 hours

- Purpose: To eliminate a part of bitter substance in orange skin

+ Put the orange pieces in the prepared saline and soak for 10 hours

+ Rinse with clean water 2-3 times to remove residual salt

+ Drain and make the process of soaking in lime water

Step 5 Soaking in lime water

- Soaking the orange with the rate of 10kg of fresh oranges in 20l of freshly prepared lime water

- Purpose: to increase the crispy of the product

- Rinse with clean water from 2-3 times to remove all lime water

- The mixing ratio between oranges and sugar is 10kg of fresh oranges and 5kg of sugar

- Purpose: Soaking the sugar will help orange pieces to soak into the sugar, and melting sugar will avoid local sugar melting when concentrated

+ Pour sugar into orange after draining, can mix sugar in brass or pan

+ After mixing sugar, let stand for 10-12 hours to infuse orange pieces

+ Concentrate the slices orange on low heat to avoid burning the product due to caramelization

+ During the concentration process, it is necessary to stir and perform gently to avoid broken orange pieces, maybe a chopstick for each hand to make the mixing easier

+ During the concentrate step, we add 20ml of honey to create a fragrance for the product

+ Orange pieces will gradually turn yellow

+ Orange pieces after concentration will be uniform yellow, have a thin layer of sugar surrouding the orange pieces

Step 8 Drying by drying oven

- Purpose: The drying process of orange jam has the effect of losing a quantity of water in the product, the jam is drier, flexible, not watery and preserved for longer

- Procedure: The drying step is used by drying ovens + Set at a temperature of 50 o C

+ Spread the orange pieces after concentrating on drying tray

+ Put the drying tray into the oven, the number of trays according to the design of the oven

+ Close the oven door and set up time to dry for 24 hours

- Purpose: To continue releasing the remaining steam in the product, and to lower the temperature of the product, helping to prevent steam when packaging

- Procedure: After drying, remove the tray from the oven Cooling the product in two ways is natural cooling and forced cooling:

+ Natural cooling: A method to cool product after drying in the room at room temperature, it will make to decrease temperature of this product from 55 o C to ambient temperature of the product after drying

+ Forced cooling: As a fan-cooling method, this cooling method has advantages over the natural cooling method which is faster cooling time, product is less changed

- Purpose: To help the product is isolated from the outside environment, prolong the time of storage of the product

Although the products are high in sugar, water content is low, the storage process will still water leakage Therefore, it is necessary to conduct cold storage at a temperature of 3 o C-5 o C to extend the shelf life of the product On a small scale, jam can be placed in the refrigerator to store it.

Establish a process for processing product orange peel