Report subject practice of dairy and related dairy production

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION

FACULTY OF CHEMICAL AND FOOD TECHNOLOGY

2 Nguyễn Quốc Huy 21116300

3 Lê Viết Anh Khôi 21116304

4 Nguyễn Thị Thu Hà 20116138

Class: PDRP410750E_23_2_02FIE Ho Chi Minh City, January 2024

TASK ROSTERS AND ASSESSMENTS TABLE

No Full name Student’s

- Lesson 1: Density, Alcohol Test

- Lesson 2: Date synthesized

- Lesson 3: Date synthesized

- Editing report word

2.3.3 Changes during incubating 19

2.4 Results and Discussion 20

2.4.1 Total amount of mixture between samples 20

LIST OF FIGURES

Figure 1.1 TH milk 2

Figure 1.2 Color and Condition 3

Figure 1.3 The first measurement 4

Figure 1.4 The second measurement 4

Figure 1.5 The third measurement 5

Figure 1.6 Alcohol test 5

Figure 1.7 After 15 minutes 6

Figure 1.8 After 1 hour 7

Figure 1.9 After 3 hours 7

Figure 1.10 pH measurement 8

Figure 1.0.11 The formula of titration 8

Figure 1.12 The result of titration 9

Figure 1.13 The criteria of titratable acidity 10

Figure 2.0.1 The commercial yogurt 15

Figure 0.2.2 The power milk (left) and fresh milk (right) 15

Figure 2.0.3 The vinamilk yogurt non sugar 16

Figure 2.0.4 Yogurt manufacturing 17

Figure 2.0.5 Pasteurization of milk 18

Figure 2.6 Average result of pH value 21

Figure 2.9 Titration of yogurt after 1 hour 30 minutes 23

Figure 2.8 Titration of yogurt after 1 hour 23

Figure 2 0.6 Titration of yogurt right after adding culture 23

Figure 2.12 Titration of yogurt after 3 hours 24

Figure 2.11 Titration of yogurt after 2 hours 30 minutes 24

Figure 2.10 Titration of yogurt after 2 hour 24

Figure 2.13 The formula for titration acidity 25

Figure 2.13 Chart of changing of acidiity in yogurt at interval time 26

Figure 2.14 The graph below depicts the pH and acidity of yogurt during fermentation 26

Figure 2.15 The yogurt 4.5% culture 27

Figure 3.1 Classification of cheese 30

Figure 3.2 Mozzarella cheese 30

Figure 3.3 Fresh cheese 31

Figure 3.4 The power milk (left) and TH true milk (right) 32

Figure 3.5 Citric acid 32

Figure 3.6 Rennet 33

Figure 3.7 Mozzarella production 34

Figure 3.8 Coagulation mozzarella 35

Figure 3.9 Kneading 36

Figure 3.0.10 Fresh cheese production 37

Figure 3.11 Coagulation fresh cheese 39

Figure 3.12 Final production 39

Figure 3.13 Final production fresh cheese 41

LIST OF TABLES

Table 1.2 Sensory evaluation of TH true milk 3

Table 1.3 The density of TH true milk 4

Table 1.4 The result of titration 9

Table 2.1 The TCVN 7030:2002 Sensory criteria 13

Table 2.2 The TCVN 7030:2002 Physical and chemical criteria 14

Table 2.3 The TCVN 7030:2002 heavy metal criteria 14

Table 2.4 The TCVN 7030:2002 Bacteria criteria 14

Table 2.5 Total amount of mixture between samples 20

Table 2.6 pH value of Yogurt sample at interval time 20

Table 2.7 Average result of pH value 21

Table 2.8 The concentration of NaOH 22

Table 2.9 Volume of NaOH use to titrate ai interval time 25

Table 2.10 The result after acidity calculation 25

Table 2.11 The sensory evaluation of yogurt 27

Table 3.1 Sensory evaluation 40

Table 3.2 Calculation 40

Table 3.3 Sensory evaluation of fresh cheese 42

Table 3.4 Calculation of fresh cheese 42

LESSON 1: MILK TESTING AND CONTROL QUALITY OF LIQUID MILK

1.1 Objective

− Checking the quality of milk

− Use techniques to test and control milk quality − Determine pH, the titratable acidity

1.2 Overview

− Milk, a nutrient-rich liquid sustenance, is secreted by the mammary glands of mammals It serves as the primary source of nourishment for young mammals, including human infants who are breastfed, until they transition to solid food Milk is obtained from lactating warm-blooded animals, encompassing species such as bovines, sheep, goats, horses, buffaloes, and others It offers vital elements like lipids and lactose for energy, proteins for amino acids and amino groups, essential fatty acids, vitamins, inorganic elements, and water.

− The composition and production of milk exhibit variations among different species, resulting in a range of health benefits Lipids present in goat and sheep milk possess anti-obesity and anti-atherogenic properties, with goat milk also acting as a prebiotic Goat milk boasts higher selenium levels, supporting the immune system, while camel milk is abundant in iron, aiding in oxygen transport Bovine milk is enriched with vitamins such as riboflavin, folic acid, B6, and vitamin A, contributing to hemoglobin synthesis Moreover, cattle milk supplies folate, and goat milk is rich in niacin, recognized for its anti-cancer properties.

1.3 Material and Procedure

1.3.1 Material

Sample preparation:

− Unexpired sterilized TH True Milk

− Purely made with fresh milk from the TH Farm

− Closed and hygienic process from grass to glass

− Immediately smell the milk.

− Observe the appearance of the milk.

− If still unable to make a clear judgment, taste the milk, but do not swallow it Spit the milk sample into a bucket provided for that purpose or into a drain basin, flush with

Purpose: The purity of milk is assessed using a lactometer test By dividing the density of milk by the density of water, it calculates the specific gravity of milk.

Color The color spans from ivory white to a gentle light cream.

Flavor The natural, inherent aroma and flavor of fresh milk, without any

unusual or foreign smells or tastes.

Impurity for

Figure 1.2 Color and Condition

Procedure:Fill the 250 mL cylinder with TH genuine milk, then submerge the lactometer in the liquid

Result and discussion

Table 1.3 The density of TH true milk No.Density (kg/m3)Temperature

Figure 1.3 The first measurement

Figure 1.4 The second measurement

 Three measurements indicate that milk has a density of 1024 kg/m3

❖ The Alcohol Test

Purpose: To detect abnormal milk, such as colostrums or mastitis milk It is based on the instability of the proteins when the levels of acid and/or rennet are increased and acted upon by alcohol as a result of disturbances in the mineral balance of milk.

Procedure: For routine testing, 5 ml of milk is mixed with 5 ml of an ethanol solution If the tested milk is of good quality, there will be no coagulation, clotting, or precipitation The presence of flakes or clots indicates poor quality milk.

Result

Discussion

Figure 1.5 The third measurement

Figure 1.6 Alcohol test

− After adding alcohol, there is no coagulation or precipitation occurrence for "TH true milk" that has been pasteurized This demonstrates that the acidity, calcium, and magnesium contents of the aforementioned milk are all within permissible bounds according to milk regulations.

❖ Test Methylene Blue

− The Methylene Blue is based on the fact that the coloring matter known as methylene blue is blue in the presence of oxygen If the dye, methylene blue, be added to fresh milk, it will give to it a blue color This blue color will remain until all the oxygen is used up when the milk will almost immediately change back to white again.

− The larger the number of bacteria in milk, the sooner this change in the color will take place Hence the use of methylene blue becomes a valuable test for determining the relative number of bacteria present in a given number of milk samples

− Prepare: Methylene blue solution is prepared by dissolving 5 mg methylene blue into 100mL distilled water The solution is stored in the refrigerator, protected from sunlight, and used within 1 week.

Procedure: Conducted under sterile conditions Take 10 ml of milk and 1 ml of methylene blue solution into a sterile test tube Shake by turning it over and over again 2-3 times Incubate at 37oC Shake every 1 hour and check the color change over time.

Result

Figure 1.7 After 15 minutes

Discussion

− Methylene blue does not change color with TH true milk because TH true milk is heat-sterilized The heat-sterilization process kills all bacteria in the milk, so there are no bacteria to use methylene blue to create blue intermediate products

− In addition, TH true milk is also processed using ultraviolet (UV) light sterilization technology This technology also has the effect of killing bacteria in milk, so TH true milk also does not change color when methylene blue is added.

Figure 1.8 After 1 hour

Figure 1.9 After 3 hours

− Therefore, it can be concluded that methylene blue does not change color with TH true milk because TH true milk is heat-sterilized and processed using UV light sterilization technology.

❖ pH Measurement

Discussion

− The pH of TH true milk is 6.64 (about 6.6 to 6.8) This is a neutral pH, which is within the safe pH range for human health TH true milk is produced from fresh cow's milk from TH farms, which are naturally grazing on pastures The milk is heat-sterilized and processed using ultraviolet (UV) light sterilization technology Therefore, TH true milk has a neutral pH, which is within the safe pH range for human health

❖ Acidity Test

Procedure: 10 ml of the milk measured into the erlen, add the water follow by ratio 1:2 and 3 drops Phenolphthalein is added Slowly drip down the NaOH 0.1N from the burette until the mixture appear pink, then stop The number of mL of Sodium hydroxide solution divided by 10 expresses the percentage of lactic acid.

Result

Figure 1.10 pH measurement

Figure 1.0.11 The formula of titration

Table 1.4 The result of titration

Volume of NaOH titrated (mL)

Discussion:

− Based on the table above, the acidity of milk is 0.137 (range 0.14±0.01) The milk quality is good and not contaminated

1.4 Conclusion

− Results are presented of the relationship of the formation of lactic acid in milk with (a) the production of acid-associated flavors, (b) the microscopic clump count, (c) the methylene blue reduction, and (d) titratable acidity

− A general relationship was noted in the lactic acid increases obtained by the colorimetric lactic acid method and by titration However, the titration results may vary appreciably from the true lactic acid changes in individual milks

− A discussion is given of the limitations and application of certain of these quality tests in a lactic acid grading program.

References

1 P Walstra, T J Geurts, A Noomen, A Jellema, M A J S van Boekel, 1999, DAIRY TECHNOLOGY principles of milk properties and processes, Department of 16 Food

Figure 1.13 The criteria of titratable acidity

Science, Wageningen Agricultural University, Wageningen, Netherlands, Marcel Dekker Inc

2 A H A Al-Shamary and N I Abdulali, 2011, Detection of microbial load in Imported UHT milk in Baghdad Markets, Al-Anbar J Vet Sci., Vol.: 4 No (2) Accessed: 02/28/2023, https://www.iasj.net/iasj/download/1deae599d1330089

3 Food Engineering Progress, 2013, Changes of Proteins and Physicochemical Properties of Cow's Milk by High Voltage Pulsed Electric Field Treatment, Sulhee Lee and Young-Seo Park, https://s.net.vn/QHtQ

LESSON 2: YOGURT PRODUCTION 2.1 Objective

− Describe and explain the yoghurt manufacturing procedure − Determine the technical parameters of yogurt processing − Applying knowledge to real-world products

− Examining the factors that affect yogurt quality during production and storage − Using ordinary laboratory equipment with mastery

− Determine pH, the titratable acidity, during fermentation − Checking the quality of yogurt

2.2 Overview

Definition

A fermented milk obtained by a simultaneous operation of L bulgaricus and S

thermophilus in which the two specific cultures remain active (living) until consumption

Thermal treatment after fermentation is not allowed Classification

On the market today, yogurt products are very diverse in terms of standard types, structures, and flavors of yogurt, which are always changed by manufacturers to suit the tastes and usage habits of customers in different countries Yogurt products can be classified as follows:

− Traditional yogurt (set type): the product has a smooth gel structure In the traditional yogurt production process, the raw milk is processed, inoculated, and then poured into the packaging Fermentation takes place in the packaging causing the appearance of a curd mass and a characteristic structure for the product

− Stirred type yogurt: the curd that appears in the product after fermentation is partially destroyed by mechanical damage During the production of stir-fried yogurt, raw milk is treated, inoculated, then fermented in specialized equipment,

then cooled and poured into packaging Yogurt will not have a smooth and uniform gel structure like traditional yogurt

− Drinking yogurt or liquid yogurt: the curd that appears in the product after the fermentation process is completely destroyed The product has a liquid form, when using the consumer does not need to use a spoon The difference is that after the fermentation process, people use stirring or homogenization to destroy the gel structure of the coagulant and reduce the viscosity of the product

− Frozen yogurt: the product is similar to ice cream The milk fermentation process is carried out in specialized equipment, then the mixture after fermentation will be treated and frozen to increase the hardness of the product and then packaged − Concentrated yogurt: the production process includes important stages such as milk

fermentation, concentration, cooling and product packaging During the concentration process, the milk serum is separated from the product Today, to diversify yogurt even 23 more on the market, people can add flavoring, food coloring or fruit purée to the product

− Yogurt cheese: is a fresh cheese created by draining and separating whey overnight The flavor is akin to sour cream and has the texture of soft cream cheese A liter of yogurt produces around 500 mL of cheese Yogurt cheese has a shelf life of 7-14 days when wrapped and refrigerated at 4°C or below

− Dried yogurt (Kurut in Turkey): Yogurt is sun dried for longer preservation Quality criteria

Based on the TCVN 7030:2002 standard for yogurt products: − The sensory criteria

Table 2.1 The TCVN 7030:2002 Sensory criteria

1 Color Milky white color or characteristic color of additional ingredients 2 Flavor, taste Features for each type of product

3 State Smooth, dense

− Considering physical and chemical markers of yogurt

Table 2.2 The TCVN 7030:2002 Physical and chemical criteria

1 Fat-free dry matter, % mass fraction, not less than 8.2

− Considering heavy metal indicators in yogurt

Table 2.3 The TCVN 7030:2002 heavy metal criteria

Fungal toxins – Aflatoxin M1 < 0.5 mg/L − Yogurt's microbiological properties

Table 2.4 The TCVN 7030:2002 Bacteria criteria

Without heat treatment

With heat treatment

1 Total number of aerobic microorganisms, number of colonies in 1 g of product

2 Coliform group, number of bacteria in 1 g of product

3 Staphylococcus aureus, number of bacteria in 1 g of product

5 Salmonella, number of bacteria in 25 g of

Some commercial products

2.3 Material and procedure 2.3.1 Material

Milk

Figure 2.0.1 The commercial yogurt

Figure 0.2.2 The power milk (left) and fresh milk (right)

In this experiment, we used both sterilized milk (11% TS) and milk powder (96%TS) to make a standardized milk with total solid content is 15%

Starter

Lactobacillus bulgaricus and Streptococcus thermophilus are the two major (starter)

microorganisms found in yogurt The starter cultures' role is to ferment lactose (milk sugar) and create lactic acid The rise in lactic acid lowers pH and causes the milk to coagulate, resulting in the soft gel typical of yoghurt In this experiment, we utilise the starter from Vinamilk yogurt (no sugar added) We purchased the product with the most recent manufacturing date in order to maximise the amount and quality of the lactic acid bacteria present The starting concentration is 4.5%

2.3.2 Procedure

Calculate raw materials

For this experiment, we used two types of milk: sterilized fresh milk and reconstituted powdered milk As a result, we had to calculate the mass of each component in order to get the final result for a yogurt product with a 15% dry matter

a: weight of sterilized fresh milk

Figure 2.0.3 The vinamilk yogurt non sugar