Milk is the secretion of mammary glands in humans and animals after childbirth. It provides complete nutrition for newborns as it contains carbohydrates, lipids, proteins, minerals, and vitamins. Milk's composition varies between species, with human milk containing less protein and minerals than cow's milk. Milk is made up of water, organic constituents like proteins (casein, lactalbumin, lactoglobulin), lipids, and carbohydrates (lactose), and inorganic constituents including minerals and vitamins. Its physical properties include white color, slightly acidic pH, specific gravity, taste, odor, and freezing/boiling points. Milk undergoes changes through processing like pasteurization, sterilization, and cheese/
This document discusses the properties and composition of milk. It begins by defining milk as the secretion of mammary glands in humans and animals after birth. Milk is the sole food for newborns and contains all the necessary nutrients for growth. The main components of milk are water, proteins (casein, whey proteins), lipids, carbohydrates (lactose), vitamins, and minerals. Milk also contains various enzymes. The physical properties of milk include its white color, pH, specific gravity, taste, odor, boiling point, and freezing point. The document provides detailed information on the composition and role of the various milk constituents.
Milk is the secretion of mammary glands in humans and animals. It provides complete nutrition for newborns as their sole food source. Milk contains water, proteins like casein, lipids, lactose, vitamins, and minerals. Casein proteins make up the majority of milk proteins and give milk its white color when suspended in colloidal casein micelles. When milk is fermented or acidified, casein proteins precipitate out to form curds. Milk's pH, fat content, protein composition and other properties can vary between species and individual animals.
Milk is the secretion of mammary glands in humans and animals. It provides complete nutrition for newborns as their sole food source. Milk contains water, proteins like casein, lipids, lactose, minerals, and vitamins. Casein is the main protein in milk and forms a colloidal suspension with calcium and phosphate. Milk also contains whey proteins like lactalbumin and lactoglobulin. The pH, specific gravity, freezing point, and other physical properties of milk can indicate its quality and composition.
The document provides an overview of milk and milk products. It discusses the composition of milk including water, carbohydrates, fat, protein, vitamins, and minerals. It also covers the flavor of milk, contamination issues, physical properties, nutritive value, and various milk products produced through processes like fermentation, evaporation, drying, and homogenization. The document concludes by describing several Indian milk products like khoa, rabri, chhaina, and ice cream.
Milk is composed of water, organic constituents like protein, lipid, carbohydrates, and inorganic constituents like minerals. The main proteins in milk are casein and whey proteins. Casein exists as micelles while whey proteins include beta-lactoglobulin and alpha-lactalbumin. Milk also contains fat in the form of globules composed mainly of triglycerides. Lactose is the major carbohydrate in milk. Inorganic constituents include important minerals like calcium and phosphorus. Milk composition can vary depending on species, breed, lactation stage, nutrition, and other factors.
This document provides an overview of milk and milk products. It discusses the composition of milk including water, fat, protein, carbohydrates, vitamins and minerals. It also covers milk flavor, contamination issues, physical properties, nutritive value, and various milk products produced through processes like fermentation, evaporation, homogenization and more. The document concludes with a discussion of common milk products like cream, butter, cheese, yogurt and ice cream.
composition of milk and its nutritive valuemohitkumar1677
Milk can be summarized as follows:
(1) Milk is defined as the lacteal secretion obtained from healthy milch animals and its composition varies by species like buffalo, cow and goat but generally contains water, fat, protein, lactose, ash, vitamins and minerals.
(2) The main constituents of milk include proteins (casein and whey), carbohydrates (lactose), fat, vitamins and minerals which provide nutrients for growth, energy, health and reproduction.
(3) The composition of milk can be affected by environmental and biological factors like species, breed, age, feeding, season, disease and milking practices.
This document discusses milk and milk products. It provides information on the composition of milk, including that milk is 87% water and contains proteins, fats, carbohydrates, vitamins, and minerals. It also discusses the types of microorganisms commonly found in milk, such as various bacteria, and microorganisms of concern for food safety. Additionally, the document outlines several factors that influence microbial growth in milk and describes various processes involved in milk processing, including clarification, homogenization, pasteurization, fortification, bleaching, and dehydration.
This document discusses the properties and composition of milk. It begins by defining milk as the secretion of mammary glands in humans and animals after birth. Milk is the sole food for newborns and contains all the necessary nutrients for growth. The main components of milk are water, proteins (casein, whey proteins), lipids, carbohydrates (lactose), vitamins, and minerals. Milk also contains various enzymes. The physical properties of milk include its white color, pH, specific gravity, taste, odor, boiling point, and freezing point. The document provides detailed information on the composition and role of the various milk constituents.
Milk is the secretion of mammary glands in humans and animals. It provides complete nutrition for newborns as their sole food source. Milk contains water, proteins like casein, lipids, lactose, vitamins, and minerals. Casein proteins make up the majority of milk proteins and give milk its white color when suspended in colloidal casein micelles. When milk is fermented or acidified, casein proteins precipitate out to form curds. Milk's pH, fat content, protein composition and other properties can vary between species and individual animals.
Milk is the secretion of mammary glands in humans and animals. It provides complete nutrition for newborns as their sole food source. Milk contains water, proteins like casein, lipids, lactose, minerals, and vitamins. Casein is the main protein in milk and forms a colloidal suspension with calcium and phosphate. Milk also contains whey proteins like lactalbumin and lactoglobulin. The pH, specific gravity, freezing point, and other physical properties of milk can indicate its quality and composition.
The document provides an overview of milk and milk products. It discusses the composition of milk including water, carbohydrates, fat, protein, vitamins, and minerals. It also covers the flavor of milk, contamination issues, physical properties, nutritive value, and various milk products produced through processes like fermentation, evaporation, drying, and homogenization. The document concludes by describing several Indian milk products like khoa, rabri, chhaina, and ice cream.
Milk is composed of water, organic constituents like protein, lipid, carbohydrates, and inorganic constituents like minerals. The main proteins in milk are casein and whey proteins. Casein exists as micelles while whey proteins include beta-lactoglobulin and alpha-lactalbumin. Milk also contains fat in the form of globules composed mainly of triglycerides. Lactose is the major carbohydrate in milk. Inorganic constituents include important minerals like calcium and phosphorus. Milk composition can vary depending on species, breed, lactation stage, nutrition, and other factors.
This document provides an overview of milk and milk products. It discusses the composition of milk including water, fat, protein, carbohydrates, vitamins and minerals. It also covers milk flavor, contamination issues, physical properties, nutritive value, and various milk products produced through processes like fermentation, evaporation, homogenization and more. The document concludes with a discussion of common milk products like cream, butter, cheese, yogurt and ice cream.
composition of milk and its nutritive valuemohitkumar1677
Milk can be summarized as follows:
(1) Milk is defined as the lacteal secretion obtained from healthy milch animals and its composition varies by species like buffalo, cow and goat but generally contains water, fat, protein, lactose, ash, vitamins and minerals.
(2) The main constituents of milk include proteins (casein and whey), carbohydrates (lactose), fat, vitamins and minerals which provide nutrients for growth, energy, health and reproduction.
(3) The composition of milk can be affected by environmental and biological factors like species, breed, age, feeding, season, disease and milking practices.
This document discusses milk and milk products. It provides information on the composition of milk, including that milk is 87% water and contains proteins, fats, carbohydrates, vitamins, and minerals. It also discusses the types of microorganisms commonly found in milk, such as various bacteria, and microorganisms of concern for food safety. Additionally, the document outlines several factors that influence microbial growth in milk and describes various processes involved in milk processing, including clarification, homogenization, pasteurization, fortification, bleaching, and dehydration.
Milk is a complex fluid that contains fat, proteins, lactose, minerals, vitamins, and other components. It exists as an emulsion with fat globules dispersed in the water-based fluid. The fat globules are encapsulated by a membrane and vary in size from 0.1 to 10 micrometers. Milk contains on average 3-4% fat consisting primarily of triglycerides with fatty acid chains of varying lengths. Other lipid components include phospholipids, cholesterol, and fat-soluble vitamins. The proteins, minerals, sugars, and other components suspend the fat globules and give milk its nutritional and physical properties.
This document summarizes the composition and biosynthesis of milk. Milk is composed of water (87%), solids (13%), proteins, lipids, carbohydrates, minerals and vitamins. The major protein in milk is casein. Milk proteins are synthesized in the mammary gland from amino acids. The main carbohydrate is lactose, which is synthesized from glucose and galactose. Milk lipids contain triglycerides and fatty acids synthesized from glucose and acetate in the mammary epithelial cells. Minerals such as calcium and phosphorus are important for bone and teeth growth in infants.
Milk
Composition of milk
physical properties of milk
Nutritive value of milk
Milk processing
Packaging of milk
Cream
Physico-chemical properties of cream
Butter
Process of butter making
Milk is defined as the fresh lacteal secretion obtained from milking healthy animals. It contains fat globules suspended in a water-based fluid and consists of various macronutrients and micronutrients. The major components of milk include water, milk fat, protein (caseins and whey proteins), lactose, and minerals. Casein proteins aggregate into micelles that are suspended in the serum and help give milk its opacity. Whey proteins remain dissolved in the serum.
This document discusses milk processing operations such as pasteurization, homogenization, and cream separation. It provides details on:
- Pasteurization methods including low temperature long time (LTLT), high temperature short time (HTST), and ultra high temperature (UHT) processing.
- Homogenization which breaks down milk fat globules to reduce creaminess and improve digestion.
- Cream separation techniques using gravity or centrifugal force to separate higher density cream from lower density skim milk.
- Other operations like standardization, mixing of ingredients, and packaging are also briefly covered. The document provides an overview of key milk processing steps and techniques.
This document discusses the physicochemical properties of milk constituents such as water, milk fat, milk proteins, lactose, and minerals. It describes the size, structure, and composition of milk fat globules. It also summarizes the types and properties of casein and whey proteins, lactose, and minor milk constituents including phospholipids, pigments, enzymes, cholesterol, and vitamins. The document then covers additional physicochemical properties of milk such as acidity, pH, density, specific gravity, freezing point, boiling point, color, and flavor.
This document provides information about milk processing operations. It begins with an introduction to milk and its composition. The main constituents of milk are water, milk fat, milk proteins, milk sugar (lactose), enzymes, vitamins, and minerals. It then describes common milk processing operations like pasteurization, homogenization, and cream separation. Pasteurization involves heating milk to high temperatures to eliminate harmful bacteria. Homogenization breaks down milk fat globules for a creamier texture. Cream separation separates milk into cream and skim milk using gravity or centrifugal force. The document also discusses standardization, mixing ingredients, and properties of milk.
1) Milk contains various proteins including caseins that coagulate when milk sours and whey proteins that remain in the whey. Milk also contains the sugar lactose.
2) Common processes used in milk production include pasteurization to kill bacteria without affecting nutrition, homogenization to reduce fat globule size, and sterilization using higher temperatures.
3) Many dairy products result from milk processing, including cheeses produced through coagulation, butter, yogurt, evaporated/condensed milks with varying water content, and dried milk powders.
This document provides an overview of dairy production, processing, and marketing. It discusses the principles of dairy farming including sustainable practices around site selection, animal health and welfare, economic stability, and environmental sustainability. It then covers the composition, biosynthesis, properties, and quality factors of milk such as interval between milking and lactation stage that can influence attributes like fat content. The document is intended to provide information on dairy farming practices and milk composition and quality.
This document provides an overview of milk processing operations. It begins with definitions of milk and its composition. The key components of milk discussed include water, fat, proteins, lactose, enzymes, vitamins, and minerals. The document then covers several milk processing operations, including pasteurization methods like low-temperature long-time and high-temperature short-time. Other operations discussed are homogenization, cream separation via gravity or centrifugal methods, standardization, and mixing ingredients.
The document discusses the composition of milk and the protein casein. It describes an experiment to quantify the amount of casein in different milk samples (cow, goat, buffalo, processed). The results showed that the percentage of casein varied between samples, with cow milk containing 3.0% casein, goat milk 3.25%, buffalo milk 4.2% and processed milk 3.88%. The document expresses thanks to the teacher and school administrators for their support.
The document analyzes the amount of casein protein present in different milk samples. Through a process of precipitation using acetic acid and saturated ammonium sulfate solution, the casein protein is separated from cow milk, goat milk, buffalo milk, and two market milk samples. The results show that cow milk contains the highest amount of casein at 7.8 grams, while buffalo milk contains the lowest at 4 grams. This indicates cow milk is most suitable for muscle growth. However, goat milk may provide an alternative for those sensitive to certain types of casein.
This document summarizes the principles of dairy production, processing, and marketing. It discusses the composition of milk, including proteins, lactose, lipids, minerals, vitamins, and enzymes. The biosynthesis of milk constituents from the mammary gland is described. Finally, it discusses the structural and physical properties of milk as an emulsion, colloid, and solution, and how processing can impact these properties. Factors that influence milk quality like milking interval and lactation stage are also summarized.
Animal Product Technology I is a fundamental course that aims to provide you with a comprehensive understanding of various aspects related to the processing and preservation of animal-derived products. As we explore this subject, we will delve into the techniques, technologies, and principles involved in transforming raw animal products into valuable commodities that meet the needs of consumers.
This document discusses milk and casein. It provides background on milk, noting that it is produced by mammary glands and is a primary source of nutrition for infant mammals. It then discusses casein, the main protein in milk, which comprises 80% of cow's milk proteins. The document presents an experiment that measures the quantity of casein in different milk samples (cow, buffalo, goat, human) by precipitating it from solution using acetic acid. It finds that heated goat milk contains the most casein at 1.4 grams, while normal goat milk contains 1.2 grams.
This document provides information on the production of dried milk and milk products. It discusses the history of dried milk, the composition of milk, and details each step of the milk powder production process from receiving and selection of raw milk to packaging and storage of the finished powder. The key steps include evaporation to concentrate the milk, drying via spray drying, drum drying or freeze drying, and quality control testing to ensure proper composition and properties. The effects of processing on powder quality attributes like solubility, bulk density and shelf life are also covered.
Milk is a complex fluid that contains fat, proteins, lactose, minerals, vitamins, and other components. It exists as an emulsion with fat globules dispersed in the water-based fluid. The fat globules are encapsulated by a membrane and vary in size from 0.1 to 10 micrometers. Milk contains on average 3-4% fat consisting primarily of triglycerides with fatty acid chains of varying lengths. Other lipid components include phospholipids, cholesterol, and fat-soluble vitamins. The proteins, minerals, sugars, and other components suspend the fat globules and give milk its nutritional and physical properties.
This document summarizes the composition and biosynthesis of milk. Milk is composed of water (87%), solids (13%), proteins, lipids, carbohydrates, minerals and vitamins. The major protein in milk is casein. Milk proteins are synthesized in the mammary gland from amino acids. The main carbohydrate is lactose, which is synthesized from glucose and galactose. Milk lipids contain triglycerides and fatty acids synthesized from glucose and acetate in the mammary epithelial cells. Minerals such as calcium and phosphorus are important for bone and teeth growth in infants.
Milk
Composition of milk
physical properties of milk
Nutritive value of milk
Milk processing
Packaging of milk
Cream
Physico-chemical properties of cream
Butter
Process of butter making
Milk is defined as the fresh lacteal secretion obtained from milking healthy animals. It contains fat globules suspended in a water-based fluid and consists of various macronutrients and micronutrients. The major components of milk include water, milk fat, protein (caseins and whey proteins), lactose, and minerals. Casein proteins aggregate into micelles that are suspended in the serum and help give milk its opacity. Whey proteins remain dissolved in the serum.
This document discusses milk processing operations such as pasteurization, homogenization, and cream separation. It provides details on:
- Pasteurization methods including low temperature long time (LTLT), high temperature short time (HTST), and ultra high temperature (UHT) processing.
- Homogenization which breaks down milk fat globules to reduce creaminess and improve digestion.
- Cream separation techniques using gravity or centrifugal force to separate higher density cream from lower density skim milk.
- Other operations like standardization, mixing of ingredients, and packaging are also briefly covered. The document provides an overview of key milk processing steps and techniques.
This document discusses the physicochemical properties of milk constituents such as water, milk fat, milk proteins, lactose, and minerals. It describes the size, structure, and composition of milk fat globules. It also summarizes the types and properties of casein and whey proteins, lactose, and minor milk constituents including phospholipids, pigments, enzymes, cholesterol, and vitamins. The document then covers additional physicochemical properties of milk such as acidity, pH, density, specific gravity, freezing point, boiling point, color, and flavor.
This document provides information about milk processing operations. It begins with an introduction to milk and its composition. The main constituents of milk are water, milk fat, milk proteins, milk sugar (lactose), enzymes, vitamins, and minerals. It then describes common milk processing operations like pasteurization, homogenization, and cream separation. Pasteurization involves heating milk to high temperatures to eliminate harmful bacteria. Homogenization breaks down milk fat globules for a creamier texture. Cream separation separates milk into cream and skim milk using gravity or centrifugal force. The document also discusses standardization, mixing ingredients, and properties of milk.
1) Milk contains various proteins including caseins that coagulate when milk sours and whey proteins that remain in the whey. Milk also contains the sugar lactose.
2) Common processes used in milk production include pasteurization to kill bacteria without affecting nutrition, homogenization to reduce fat globule size, and sterilization using higher temperatures.
3) Many dairy products result from milk processing, including cheeses produced through coagulation, butter, yogurt, evaporated/condensed milks with varying water content, and dried milk powders.
This document provides an overview of dairy production, processing, and marketing. It discusses the principles of dairy farming including sustainable practices around site selection, animal health and welfare, economic stability, and environmental sustainability. It then covers the composition, biosynthesis, properties, and quality factors of milk such as interval between milking and lactation stage that can influence attributes like fat content. The document is intended to provide information on dairy farming practices and milk composition and quality.
This document provides an overview of milk processing operations. It begins with definitions of milk and its composition. The key components of milk discussed include water, fat, proteins, lactose, enzymes, vitamins, and minerals. The document then covers several milk processing operations, including pasteurization methods like low-temperature long-time and high-temperature short-time. Other operations discussed are homogenization, cream separation via gravity or centrifugal methods, standardization, and mixing ingredients.
The document discusses the composition of milk and the protein casein. It describes an experiment to quantify the amount of casein in different milk samples (cow, goat, buffalo, processed). The results showed that the percentage of casein varied between samples, with cow milk containing 3.0% casein, goat milk 3.25%, buffalo milk 4.2% and processed milk 3.88%. The document expresses thanks to the teacher and school administrators for their support.
The document analyzes the amount of casein protein present in different milk samples. Through a process of precipitation using acetic acid and saturated ammonium sulfate solution, the casein protein is separated from cow milk, goat milk, buffalo milk, and two market milk samples. The results show that cow milk contains the highest amount of casein at 7.8 grams, while buffalo milk contains the lowest at 4 grams. This indicates cow milk is most suitable for muscle growth. However, goat milk may provide an alternative for those sensitive to certain types of casein.
This document summarizes the principles of dairy production, processing, and marketing. It discusses the composition of milk, including proteins, lactose, lipids, minerals, vitamins, and enzymes. The biosynthesis of milk constituents from the mammary gland is described. Finally, it discusses the structural and physical properties of milk as an emulsion, colloid, and solution, and how processing can impact these properties. Factors that influence milk quality like milking interval and lactation stage are also summarized.
Animal Product Technology I is a fundamental course that aims to provide you with a comprehensive understanding of various aspects related to the processing and preservation of animal-derived products. As we explore this subject, we will delve into the techniques, technologies, and principles involved in transforming raw animal products into valuable commodities that meet the needs of consumers.
This document discusses milk and casein. It provides background on milk, noting that it is produced by mammary glands and is a primary source of nutrition for infant mammals. It then discusses casein, the main protein in milk, which comprises 80% of cow's milk proteins. The document presents an experiment that measures the quantity of casein in different milk samples (cow, buffalo, goat, human) by precipitating it from solution using acetic acid. It finds that heated goat milk contains the most casein at 1.4 grams, while normal goat milk contains 1.2 grams.
This document provides information on the production of dried milk and milk products. It discusses the history of dried milk, the composition of milk, and details each step of the milk powder production process from receiving and selection of raw milk to packaging and storage of the finished powder. The key steps include evaporation to concentrate the milk, drying via spray drying, drum drying or freeze drying, and quality control testing to ensure proper composition and properties. The effects of processing on powder quality attributes like solubility, bulk density and shelf life are also covered.
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2. Def:
It is the secretion of mammary glands in human and animals
after labour.
It is the only food for newborn for a long period till weaning
time.
Before birth the fetus receives its nutrition through the
placenta.
2
3. Milk secretion is stimulated by Prolactin.
Milk flow is decreased by Estrogen and
Progesterone while increased by
Thyroxin.
Also Squalene present in HELBA
increase milk flow.
Initiation of lactation may result from
sudden removal of the placenta and other
factors.
Oxytocin (posterior pituitary hormone)
responsible for milk ejection
3
4. Milk is considered as a complete diet as:-
It contains all of the components necessary for growth,
maintenance of life and reproduction.
e.g:
Carbohydrates, Lipid, Protein, Minerals and Vitamins.
But, it is deficient in:
Vitamin C, Vitamin D, Vitamin K, Iron, Copper
4
6. Property 1- Color
White color → due to presence of:
Fat globules in emulsion form.
Protein in colloidal form.
Ca. phosphate and Ca. Casinate.
Yellowish (creamy) color → due to presence of
Carotene and
Xanthophyll pigments (specially in cow's milk) and
colostrums (1st fresh milk in pregnancy).
6
7. Property 2 - Reaction
Fresh milk is amphoteric in reaction as it contains acid & base.
Milk is an excellent buffer as it contain:
Protein.
Phosphate.
Bicarbonate.
Citrate.
pH of fresh milk:
6.6 – 6.8 Cow's milk.
6.8 – 7.4 Human's milk
Milk pH is changed to alkaline in case of:
Mastitis
Late period of lactation.
If the milk left to stand for a long period specially in warm
temperature, lactose is fermented to lactic acid by bacteria present
normally in milk as:
Streptococcus Lactis
Lactobacillus Lactis
7
8. Property 3 – Specific Gravity
It is the ratio between weight of a given volume of milk
compared with the same volume of water at a specific
temperature. Measured by Lactometer
It measure total solids of milk, and determine if any
constituent added or removed from milk..
Normal specific gravity:
1020 – 1030 Cow's milk.
1030 – 1035 Human's milk.
Fat is the only constituent in milk with specific gravity
lower than 1000, so, when fat present in milk in high
amount, specific gravity decrease than normal values.
8
9. Property 4 – Taste
Normal characteristic milky taste.
Milk taste changed in case of :
Souring: due to increased acidity.
Boiling: due to certain biochemical changes and
evaporation of volatile fatty acids.
Late stage of lactation: due to increase chloride
percent.
Mastitis: inflammation of udder.
Property 5 - Odor
Characteristic milky odor
9
10. Property 6 – Freezing point of milk
It is the temperature at which the liquid milk freeze or
crystallize.
The freezing point of cow or buffalo milk ranges from (-
0.53) to (-0.57) °C with average (-0.55) °C
Milk freezes at a temperature slightly lower than that of
water due to the soluble constituents in milk such as
lactose, minerals which lower the freezing point.
This test is important for detection of the amount of water
added to pure milk
10
11. Addition of Water to Milk
The addition of 9% water to milk will raise the
freezing point by 0.05 °C.
i.e., if milk freezing point is -0.45 °C, it means addition
of 18% water.
-0.45 – (-0.55) = -0.45 + 0.55 = +0.10
0.05 → 9 %
0.10 → X
X = = 18 %
9x0.1
0.05
11
12. Property 7 – Boiling Point
Milk boiling point is 100.5 °C , more than water due to
presence of dissolving substances
Property 8 – Cream Line Formation
When milk left at room temperature the fat globules
coalesce, clumped at surface of the container and form
cream line.
12
16. 1- Protein:
Milk protein less in human than in cow's milk.
All milk protein synthesized in the mammary gland.
Milk protein of high coefficient digestibility (85 – 95%)
X 100
Amount of N2 absorbed
Total N2 in the protein
Total amount of protein differ according to species and affect
rate of growth
Young rabbit reach double weight in 5 days as milk protein 10 gm/dl.
Young calf reaches double weight in 50 days as milk protein 3.7 gm/dl.
Young child reach double weight in 5 - 8 months as milk protein 1.5 gm/dl.
16
18. (i) Casein
It is the main and most dominant milk protein.
Casein is the only milk protein that not coagulated on
boiling.
It represents 25% in human's milk and 83% in cow's
milk.
It is a compound protein (Phospho-protein) of high
biological value.
The high phosphate content of casein allows it to
associate with calcium and form calcium phosphate
salts.
So, at normal PH of fresh milk (6.6 PH)
casein present as insoluble Ca. caseinate
phosphate complex.
18
19. Casein is deficient in cystiene and cystin so give negative
result with sulpher test.
Casein : (Lactalbumin - Lactglobulin) ratio is 1:3 which
facilitate its digestion.
According to molecular weight and electrophoresis
process, casein is separated in to 3 fractions, each one of
them has its own amino acid composition :
α Casein → 75%.
β Casein → 22%.
γ Casein → 3%.
1
=
Casein
3
Lactalbumin + Lactglobulin
19
22. Milk Souring (Milk Curdling – Zabadi)
The principle of coagulation, or curd formation, at acidic
pH is the basis for Yoghurt (Zabadi) formation. How?
Fermentation of lactose to lactic acid by:
Lactic acid producing bacteria present normally in milk.
Addition of acid (acetic acid).
Addition of starter culture (yoghurt).
Lactose + lactic acid bacteria Lactic acid ↓ pH
Worm temp.
Fermentation
22
23. Milk Clotting (Cheese Manufacturing)
During digestion (in new born):
Rennin enzyme acts on casein, converting it to soluble
Paracaseinate which is bounded to Ca and form insoluble
Ca. paracaseinate (milk clot).
Rennin enzyme:
Derived from 4th stomach of calves and used externally in
cheese manufacture.
It is secreted inactive as pro-rennin.
Its optimum PH 4.
It is absent in adult stomach.
Formation of milk clot: prevents rapid passage of milk from
stomach to intestine so give the sense of fullness to
newborn.
23
25. (ii) Lactalbumin
Represent 87% of whey protein.
PPT by full saturation with ammonium sulphate.
Rich in cystein and cystin so give +ve result with sulpher test.
Simple, soluble and easily digested protein.
Consists of two fractions:
α Lactalbumin 32% of whey protein.
β lactglobulin 55% of whey protein.
Where,
β lactglobulin called globulin because it need small amount of
NaCl to be dissolved but it is not PPT by half saturation as
albumin.
25
26. (iii) Lactglobulin
Represent 13% of whey protein.
PPT by half saturation with ammonium sulphate solution.
Rich in cystein and cystin so give +ve result with sulpher test.
Simple, soluble and easily digested protein.
Consists of two fractions:
True globulin (Euglobulin) 50%.
False globulin (Pseudoglobulin) 50%.
They carry antibodies causing immunity so called
immunoglobulins.
They present in higher concentration in colostrum.
26
28. 1- Catalase:
Carried by fat globules.
Act on hydrogen peroxide (H2O2) producing water and
oxygen.
Increased in case of mastitis.
2- Xanthin oxidase:
Carried by fat globules.
Act on hypoxanthin and xanthin to produce uric acid.
Milk enzymes
28
29. 3- Peroxidase:
Carried by lactalbumin.
Act on hydrogen peroxide (H2O2).
It is heat stable enzyme (resist destruction by heat).
It is destroyed by milk sterilization.
Milk sterilization:
Heating of milk to 116◦C for 15 minutes which destroy all
harmful and non harmful microorganisms.
Milk sterilization leads to alteration in milk taste and
destruction of vitamin C and vitamin B2.
N.B:
Absence of peroxidase enzyme indicates milk sterilization.
Milk enzymes
29
30. 4 - Alkaline phophatase:
Carried by fat globules.
Catalyze hydrolysis of phosphate ester.
Destroyed by the same temperature that destroys the
harmful bacteria.
e.g:
Tubercle bacilli.
Absence of Alkaline phophatase enzyme indicates milk
pasteurization.
Milk pasteurization:
Heating of milk to 60◦C for 30 minutes or 70◦C for 15 minutes
followed by sudden cooling which destroy the harmful
microorganisms only.
Milk enzymes
30
31. 5- Amylase:
Carried by lactalbumin.
Catalyze hydrolysis of α 1, 4 glycosidic linkage of starch and glycogen.
Increased in case of mastitis.
Milk enzymes
6- Lipase:
Carried by casein.
Catalyze hydrolysis of primary ester linkage in triacylglycerol.
Act on milk fat producing free fatty acids and undesirable taste
(Rancidity).
7- Aldehyde oxidase (Schardinger's enzyme):
Its absence indicates milk boiling.
Schardinger's test:
Milk + Methyl blue + Formaldehyde
Blue color appeared in case of boiled milk.
Colorless in case of unboiled milk.
31
32. Beside milk proteins milk also contains:
A) Lactoferrin binding protein:
It contains iron which is bounded to a glycoprotein.
It facilitates iron transport and storage.
Found in high concentration in human colostrums and milk.
B) Vitamin B12 binding protein:
It carries vitamin B12.
Lactoferrin and vitamin B12 binding protein deprive
pathogenic intestinal bacteria from iron and vitamin B12 so
they have bacteriostatic action.
32
34. C) Carbohydrates:
Lactose (milk sugar) is the only carbohydrate of milk.
It is a reducing disaccharide consists of glucose and
galactose.
Human's milk contains 7% lactose while cow's milk contains
5% lactose.
Lactose may be excreted in urine during last third of
pregnancy physiologically so it should be differentiated from
glucose by osazon test.
34
36. 1- Minerals:
Human milk contain less mineral elements (0.4%) than cow's milk (0.8%).
Milk rich in Ca and P which are present in their proper ratio for
absorption (2:1) in human milk while in cow's milk (1:2) which is not
suitable for their maximum absorption .
Ca and P are essential for:
1. Growth of bone and teeth.
2. Stability of casein.
Milk is deficient in Fe and Cu which are supplied by their storage in
liver during prenatal life (this store is sufficient till weaning time).
N.B:
Milk is deficient in Iron but it is more in human milk than cow's milk
Thus anaemia in breast feeding is less common.
Milk contain adequate amount of Na, K, Mg.
Human milk contains Na:K (1:2) which is suitable for the optimal
growth of newborn.
36
37. 2- Vitamins:
Milk is deficient in: Vitamin C, Vitamin D, Vitamin K.
Milk contain adequate amount of vitamin B complex which are sufficient
for first week of life. e.g: Pantothenic acid
Although milk is deficient in Fe, Cu, vitamin C, vitamin D, and vitamin K it
is complete natural food for the following reasons:
1. Easily digested absorbed and metabolized.
2. Contain all the nutrients required for the newborn at early stage of
life.
3. Balanced ratio between carbohydrates, lipid and protein.
4. Milk Protein of high biological value as:
It contains all essential amino acids.
Easily digested.
Easily absorbed.
Easily metabolized.
37
39. Definition:
It is a process by which cow's milk is made to be as near as
human's milk.
Aim:
Protein of human's milk (casein) form 25% of milk protein
while casein in cow's milk form 5/6 of milk protein so it
form dense clot in newborn stomach which can't be
digested leading to vomition.
Lactose in human's milk higher than that in cow's milk
(7:5).
39
40. Steps:
1. Pasteurization of milk:
Heating of milk to 60 ◦C for 30 minutes followed by sudden
cooling then the pasteurized milk left in cool place for 4 hours
to allow separation of cream.
2. Separate the cream and the residual milk called
Skimmed milk.
3. Skimmed milk is divided to two halves.
To one half add:
Separated cream.
Equal amount of water.
Complete lactose to 7%.
Iron, vitamin C, vitamin D may be added.
4. Mix well then sterilize the milk:
Heating of milk to 116 ◦C for 15 minutes.
40
41. Advantages of human milk (Breast Feeding)
1. Psychological effect on both child and mother.
2. Breast milk is supplied in suitable temperature.
3. Sterile and not liable to be contaminated.
4. Cheaper than animal milk.
5. Not liable to adulteration.
6. Lactation may act as a contraceptive measure.
7. Lactation minimize the risk of breast tumors.
8. Lactation help involution of the uterus.
41
43. Defn: Lactose in milk is estimated in the clear filtrate after
precipitating proteins. Tungestic acid, and
Trichloroacetic acid can be used to precipitate milk
proteins.
Useful Instruments:
1. Estimated pipette.
2. Volumetric flask.
3. Funnel.
4. Beaker.
5. Burette.
6. Burette holder.
7. Porcelain dish.
43
44. Procedures:
a) PPT of casein:
In a clean dry volumetric flask add:
5ml of milk
5ml of 10% sodium tungstate solution
5ml of 2/3 N sulphuric acid drop by drop.
Shake gently after each addition .
Complete to the 100-ml mark by distilled water.
Left for sometime (1/4 – 1/2 hr) until the precipitate of
casein settles down.
b) Filtration:
Filter into a dry clean beaker.
The filtrate must be clear, if not refilter again
44
45. c) Reduction:
When about half the volume is filtered, wash the burette
with little of the filtrate.
Then fill the burette with the filtrate.
In a porcelain dish place:
10 ml of Fehling’s solution.
20 ml of distilled water.
Heat the Fehling’s solution until it gently boils and
Begin the reduction adding the filtrate slowly and regularly
in order to keep Fehling’s solution boiling all the time.
Continue the reduction until the last trace of blue color is
just discharged.
45
46. d) Calculation:
R = number of mls of the filterate used for complete
reduction of fehling’s solution.
10 ml Fehling’s solution are completely reduced by
0.0678 gm lactose.
Total dilution of milk (T.D):
Lactose in milk (g%):
0.0678 x 20 x 100
Lactose in milk =
R
100
20 =
5
46
48. Principle of the test:
The quantitative determination of glucose or lactose in
gm/dl in the solution depends upon their reducing
property to Fehling’s solution.
Instruments used in the estimation:
Pipette 5 and 10-ml capacity.
Conical flask of 100 cc capacity.
Burette 50 ml capacity
Burette holder.
Porcelain dish.
Beaker.
48
49. Reagents and solutions required:
Glucose or lactose, solution under estimation.
Fehling quantitative reagent.
Potassium ferrocyanide acidified with glacial acetic acid
(external indicator).
Significance of the test:
This test considered the bases of tests used for the
determination of blood glucose.
Used for estimation of lactose in milk, for detection of
adulteration of milk by the addition of water.
49
50. procedures:
(A) Rough estimation:
Fill the burette with glucose or lactose solution after its careful
rinsing with water.
Put in the porcelain dish
10-ml of Fehling quantitative reagent.
20 ml of distilled.
Heat until the Fehling boils in the dish.
Begin the reduction by slow addition of solution in order to
keep the Fehling boiling all the time.
Continue reduction till the last trace of the blue color of the
Fehling’s reagent turn to red brown PPT of Cu2O.
Record the rough reading R (number of mls of glucose or
lactose descended from the burette).
If the (R) rough reading is below 5ml make dilution to the
glucose or the lactose solution under the estimation.
If the (R) rough reading is above 5ml calculate the percentage of
glucose or the lactose solution under the estimation.
50
51. (B) Preparation of diluted sugar solution:
Mutiply the (R) by 4.
The result is equaled to 5, 10 or 20.
In 100 ml volumetric flask add:
? ml of the glucose or lactose sugar solution.
Completed with distilled water to 100 ml mark and well
mixed.
In this case the sugar solution is diluted 5, 10 or 20 times.
51
52. (C) Accurate estimation:
Wash the burette with distilled water and rinse it with little of
diluted sugar,
fill it again with the diluted sugar.
In the porcelain dish add:
10 ml of Fehling’s quantitative solution.
20 ml of distilled water.
Heat till gentile boiling.
Begin the reduction by slow addition of the diluted sugar
solution drop by drop in order to keep the Fehling’s solution
boiling all the time.
Continue reduction till the last trace of the blue color
disappeared and changed to red brown PPT of Cu2O
52
53. Using an external indicator near the end point (Potassium
Ferrocyanide solution acidified with Glacial Acetic acid) to
ensure the complete reduction of Fehling's solution:
If no brown color or PPT is formed on the addition of one
drop of the solution to the external indicator it indicates:
complete reduction of Fehling's solution.
If brown color or PPT appeared it indicates:
Incomplete reduction of Fehling's solution.
Complete reduction till the yellow color of the indicator
doesn’t change.
Record the number of mls used for reduction of 10 ml Fehling’s
quantitative solution and give it symbol (V) ml.
53
54. (D) Calculation:
10 ml Fehling’s solution are completely reduced by 0.0678 gm
lactose.
g/dl
0.0678 x T.D x 100
Lactose in solution =
V
g/dl
0.0678 x 100
Lactose in solution =
R
10 ml Fehling’s solution are completely reduced by 0.05 gm
glucose.
g/dl
0.05 x 100
Glucose in solution =
R
g/dl
0.05 x T.D x 100
Glucose in solution =
V
54