Chemistry and physics of milk and dairy products. Milk and fermented milk products - chemistry - it's interesting - fascinating chemistry - catalog of articles - call for a lesson
Lesson objectives:
- Educational:
- familiarizing students with the basics of nutrition with dairy and lactic acid products, with the dependence of the quality of dairy products on the environmental situation of the area;
- familiarizing students with methods for determining the quality of milk and lactic acid products.
- Developmental:
- development of students’ ability and skills to conduct a brief chemical analysis of the quality of milk and lactic acid food products.
- Educational:
- Show students, using specific examples, the opinions and statements of many experts about the positive and negative qualities of milk and its products, their impact on the human digestive system.
Intersubject connection:
- biology + chemistry – proteins, fats, carbohydrates, vitamins;
- chemistry - rules for using laboratory equipment and chemical reagents;
- labor training – general characteristics of food products;
- cooking – milk and lactic acid products.
Sayings:
- “If excessive and exclusive passion for food is animalism, then any inattention to food is imprudence.” (I. P. Pavlov)
- “When studying, experimenting, observing, try not to remain at the surface of the facts. Try to penetrate the mystery of their origin. Persistently seek the laws that govern them.” (I. P. Pavlov)
Equipment: stand for test tubes, posters and paintings depicting milk and fermented milk products.
Signed tubes: acetic acid, copper hydroxide solution, alcohol
phenolphthalein solution, 5 g of cottage cheese, 40 ml of milk, 0.1 molar sodium hydroxide solution. Burettes filled with 0.1 molar sodium hydroxide solution. Tap water. Distilled water, 0.5 liters of milk; 10% hydrochloric acid solution. Test tube holder – 2 pcs., box of matches, stand for fuel. Dry fuel – 1 tablet. Chemical beaker 150-200 ml., test tubes 10 pcs.
DURING THE CLASSES
Introductory word from the teacher. Basics of rational nutrition
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Milk is one of the complete, universal food products. Academician I.P. Pavlov spoke about milk: “Milk is a food that is prepared by nature itself, and is easy to digest and nutritious.
Since ancient times, milk has been a healing agent. Doctors Ancient Egypt, and after them Hippocrates used them to treat many diseases of donkey milk. Aristotle, Pliny, Herodotus argued that in Ancient Greece Goat's and mare's milk were used to cure a disease such as pulmonary tuberculosis, and cow's milk was used to cure anemia. Already in the 17th century, fresh milk began to be used as a therapeutic and prophylactic agent in almost all European countries. So milk was used for illnesses nervous system, gastrointestinal tract, gout, anemia and used as an antidote. They treated cardiovascular failure, bronchitis, pleurisy, bronchial asthma, gastritis, obesity, kidney and liver diseases. In 1880, Academician A. A. Ostroumov proposed treating diseases of the stomach and intestines with a mixture of baked milk and oatmeal broth.
Milk consists of 88.1 – 91.4% water and 4.7 – 6.4 g %
lactose, which is part of complex organic compounds. Also, whole fresh cow's milk contains methionine, choline, and lecithin, which give milk lipotropic, i.e., anti-atherosclerotic activity. Lecithin also has antibacterial properties.
The energy value of milk is 58 kcal. per 100 g of product. With large consumption of milk, appetite may decrease to a certain extent. This is of course undesirable, but the dairy diet does a good job.
Today we are teaching you a lesson role playing game by chemical determination of milk quality. When conducting chemical analysis, follow the rules for T/B that we studied earlier.
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Director of a dairy products plant (dairy plant):
– Dear friends, colleagues! Today, at an emergency meeting in my presence, I gathered the leading specialists of our enterprise to resolve an important issue concerning the future path of our products, and the enterprise itself as a whole. You know that there were years when we were the only monopolist of dairy products in our city market. Now things are different. Dairy products from other enterprises in our region and even other regions of our country are imported into our city. In order to preserve our brand in the future, I would like to listen to the opinions of our departments on their work in this area and what products should we release more into our stores so that they do not linger on the shelves. So, I'm listening to your opinions.
Chief technologist: I think the next word is mine. You know that the dairy industry sells bottled milk, pasteurized milk in packages, kefir, yogurt, fermented baked milk, as well as sour cream, cottage cheese, curd cheese, a creamy drink, various types of ice cream, and powdered milk, which is prepared from whole or skim milk. Our plant is armed with the most advanced technology, there are automatic machines, units for pasteurization, cooling, storage, and bottling of milk. Our level of automation is very high, all processes are done without touching hands. IN Lately we can produce such a dietary, medicinal drink as kumiss. We prepare it from mare's or cow's milk (cow's milk is mixed with whey and sugar). Benign kumiss has White color with a grayish tint, pleasant, sour-alcohol taste and smell. Weak (one-day) koumiss contains up to 1% alcohol, medium (two-day) - 1.75%, strong (three-day) - 2.5%. Milk is fermented with lactic acid bacteria and lactic yeast, resulting in both lactic acid and alcoholic fermentation. We have also already launched production and are producing domestic yoghurts with various fillings.
Director of the dairy plant. I understand everything. With this arrangement, we can maintain the brand of our plant's dairy products.
This is certainly true. Our laboratory staff have found that milk contains all the nutrients necessary for the proper development and functioning of the human body. The fats, proteins and carbohydrates of milk are easily and almost completely digestible, and the presence of vitamins A, C, B1, B2, D, E and mineral salts in this product significantly increases its nutritional value. Due to its chemical composition and low melting point, milk fat is one of the most complete and easily digestible; it is found in milk in the form of tiny balls. Whole, unskimmed milk must contain at least 3.2% fat.
Chief technologist. I would like to clarify the following. Does the organic chemistry laboratory have data on the chemical composition and calorie content of different types of milk?
Director of the dairy plant. The question is significant. I was also interested in the chemical composition of milk and especially the calorie content, because there are a lot of misconceptions among scientists and nutritionists about the benefits of milk. Or maybe they are right in this matter? What do you say to this?
Laboratory of Organic Chemistry. To this question we can answer that the materials you are interested in may be in the analytical chemistry laboratory, they are doing this. So, this is for the analysts, they have the floor.
Yes, we have the material you are interested in. We study and determine the chemical composition of milk and the caloric value of various types of this product. There are no secrets in this. And we can say that drinking milk should be 500 g per day in a person’s diet. It was determined that its composition includes; water, milk sugar, proteins, milk fat, minerals, vitamins, enzymes and hormones. The vitamin composition of milk is very diverse. Of the 12 vitamins contained in milk, the main ones are vitamins such as: A, D1, D2, B2, carotene. With milk and dairy products, the human body’s need for vitamins A and B and partially for vitamins C and D can be fully satisfied. Largest quantity vitamin A in summer milk. Here is a table in front of you, reflecting that in terms of calorie content, deer milk comes first, then sheep and buffalo milk. Cow - is in sixth place.
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Chemical composition and calorie content of milk from agricultural animals:
Milk |
In 100 g of milk, in g |
Calorie content kcal per 1 kg |
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dry matter |
milksugar |
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| DEER SHEEP BUFFALO CAMEL GOAT COW |
63,3 |
36,7 |
10,3 |
22,5 |
2,5 |
2725 |
Laboratory of general chemistry. The department of the laboratory of general chemistry can complement its analytical colleagues that of the various mineral salts of milk, calcium and phosphorus salts are of greatest importance. The ratio of these salts in milk ensures high absorption of both elements. When milk is included in the diet, the absorption of calcium salts contained in other products increases. The iron contained in milk is also easily absorbed. Our department believes and is of the opinion that it is necessary to continue the production of dairy products from our plant, increasing and expanding its range, without fear of competition. We must survive and displace our competitors by improving the quality of our products. Only by quality and very high quality can we make foreign names of products disappear, preserving our true Russian names of milk and dairy products.
Laboratory of Organic Chemistry. Organics agree and support the opinion of the general chemistry laboratory department. We believe and defend our point of view that milk and milk fat are among the most complete in terms of nutritional and biological properties. Milk fat is absorbed by the human body by 95 %. When milk is stored, the fat globules rise to form a layer of cream. Milk proteins are absorbed almost completely by the human body (up to 98%). They contain amino acids necessary for humans. The main carbohydrate in milk is milk sugar or, as it is also called, lactose. In the intestines, where the digestion process takes place, lactose is broken down and does not cause intense fermentation. This helps reduce putrefactive processes and has a beneficial effect on the digestive process as a whole. Lactose is absorbed quite slowly compared to other sugars and due to this lactose is absorbed almost completely - by 98 %. I see that, in my opinion, the nutritionist wants to supplement something.
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Nutritionist. I am a nutritionist. Your director invited me to this meeting so that all of you sitting here could hear the opinions of nutritionists on your main product - milk. Regarding the use of milk for food, it can be noted that our ancestors consumed this food product for thousands of years. But they preferred goat milk, since they mainly raised goats and sheep, this is the first thing. Secondly, even if you take the cow's milk that we drink today, it will not be like the milk that we drank just a century ago: its proteins, as a result of heat treatment during the pasteurization process, have changed. And if you look at this from the point of view of evolution, we can firmly say that our body cannot adapt to this product in any way over long millennia. It is the root of many diseases, such as chronic runny nose, migraine, urticaria, asthma, eczema, joint pain and others. The mechanisms involved in the formation of food intolerance are very difficult to determine. But it can be assumed that the digestive system plays a role here. Incompletely digested particles of dairy products enter the bloodstream and spread throughout the body, causing various ailments. My opinion would be this: you can, of course, eat milk, but in very limited quantities. Which ones? And this must be determined by the body itself - by responses to irritation of the mucous membrane of the stomach and intestines, which include: pain and cramping in the abdomen, bloating, quality of stool, diarrhea, increased fatigue. I think that a representative of the biochemical laboratory will definitely join my presentation.
Laboratory of Biochemistry. Biochemists believe that many cases of milk intolerance are caused by lactose, a form of sugar found in milk. A number of people do not digest milk fat, but low-fat dairy products and skim milk do not harm the body. Therefore, sadly, you need to exclude fatty milk, cheese and butter from your diet. Milk intolerance is associated with insufficient amounts of the enzyme lactose in the intestinal juice. And in this case, milk sugar is not broken down in the intestines and becomes toxic to the body. Due to this, various diseases are caused. It should also be noted that for people who digest milk, the most complete milk is freshly milked, fresh. It is bactericidal, that is, it can trap and even kill bacteria that enter milk. To preserve the bactericidal properties of fresh milk, it is cooled. At a temperature of 30°C, bactericidal activity lasts for 3 hours, at 15°C for about 8 hours, at 10°C for about 24 hours. Despite the fact that a certain percentage of people cannot tolerate milk...
Director of the dairy plant. Could you say what percentage, that is, clarify this percentage?
Laboratory of Biochemistry. We cannot say a certain percentage, since there is none. It changes from year to year and its quantity has recently been strongly influenced by various environmental factors. So, continuing where I left off, our laboratory considers it appropriate to continue to consume milk and various dairy products, expanding their range.
Cosmetologist. I wanted to touch on the cosmetology of milk.
Director of the dairy plant. Please, we are listening to you very carefully. I think it will be interesting - milk cosmetology. New, forgotten is old, isn’t it?
Cosmetologist. One could say so. Many of our ancestors used milk as food, that is, a food product, and as a cosmetic product and medicine. According to old recipes, milk was used in the treatment of sore throats, poisoning and intoxication. I am sure that women would not refuse to take a bath from Queen Cleopatra, who regularly bathed in... milk, thereby prolonging her youth. But the Egyptian queen had her own herd and cow farm. And milk was supplied to her immediately after milking. Here is the secret of youth.
Director of the dairy plant. Yes, this is the most ancient perfection of female beauty. One can only admire him. The nutritionist asks to speak. Please.
Nutritionist. I can only complement organic and biochemists with the fact that exclusion of milk and lactic acid products from the diet can cause calcium, vitamin B and iron deficiency. This deficiency can be compensated for by choosing the right diet of vitamin and mineral supplements. If this is not done on time, anemia and various diseases of the nervous system may develop.
Director of the dairy plant. What will the technical department for pasteurization and sterilization of milk say?
Department of pasteurization and sterilization. We produce pasteurized and sterilized milk.
Pasteurized milk obtained by heating raw milk for 15-20 seconds at a temperature of 74-76°C. There are the following types of milk: whole, high-fat, low-fat, protein, low-fat, fortified, baked.
Whole– contains milk fat 3.2%.
Increased fat content– milk fat – up to 6%, add cream.
Protein– fat – up to 2% – 2.5%, protein – up to 5.5%, obtained from a mixture of whole and skimmed milk powder. Dietary product for people with protein deficiency
insufficiency.
Low-fat milk– fat no more than 0.05%, obtained by removing cream.
Low fat milk– fat removal up to 2.5%.
Fortified– add vitamin C to whole milk (100 mg per 1 kg).
Ghee– obtained by simmering pasteurized milk in closed containers for 3-4 hours at a temperature of 95-99°C. Pasteurized milk is a perishable product. It is stored at temperatures up to 6°C. Milk can be stored at room temperature for no more than a day.
Second employee of the pasteurization and sterilization department. Sterilized milk is obtained by heating milk under conditions that ensure the destruction of not only bacteria, but also their spores. Milk is sterilized at high pressure for up to 10 seconds at a temperature of 125-145°C. In order to prevent cream from settling and increase the digestibility of milk, homogenization (crushing of fat globules) is carried out before sterilization. After sterilization, the milk is cooled and then packaged. In this case, sterilization may be disrupted. Therefore, repeated sterilization is carried out. Such milk is called “Mozhaisk”, and sterilization is carried out for several minutes at 115-120°C. We also produce various fermented milk products. We join the opinion of those who advocated the continuation of the production of various dairy products, observing all technological standards and safety regulations when processing milk.
Director of the dairy plant. The position of all departments and the laboratory is completely clear to me. I also support the opinions of all the speakers that milk and fermented milk products play an important role in the diet of many people. Only by high quality can we maintain the high brand of our dairy plant hometown. And now I want to address you with a production request directly related to your work - to conduct a mini-chemical analysis of newly arrived milk and an analysis of the acidity of our competitors’ cottage cheese. After work, we will summarize your research on some aspects of the quality of milk and cottage cheese. So, please start researching.
Carrying out chemical analysis
Determination of lactose (milk sugar) in milk
Cow's milk contains about 4.5% lactose. It is an isomer of sucrose and gives a silver mirror reaction (also a copper one). Milk sugar is less soluble and sweet than beet sugar. When hydrolyzed, milk sugar produces two monosaccharides - glucose and galactose.
To detect milk sugar, you need to take 20 ml of milk, then add the same amount of water and a few drops of acetic acid to curdle the milk. When casein is isolated, it is filtered. An ammonia solution of silver nitrate (5 ml of silver nitrate + 2-3 drops of ammonia) is added to 10 ml of the filtrate and heated - silver mirror reaction - metallic silver is released. You can replace silver nitrate with a freshly prepared solution of copper hydroxide (5 ml of copper sulfate solution + 1-2 ml of sodium hydroxide solution). Then, as in the first case, a little copper hydroxide is added to 10 ml of the filtrate and heated - the reaction of the copper mirror is a red-yellow color.
Determination of milk acidity
10 ml of the test milk, 20 ml of distilled water and 5 drops of a 2% alcohol solution of phenolphthalein are poured into a beaker. Then the mixture is shaken well and a 0.1-molar solution of sodium hydroxide is added dropwise from a burette until it turns noticeably pink. The number of milliliters of caustic soda solution used is multiplied by 10. The acidity of the milk is obtained in conventional degrees Turner. Fresh milk has 16-18 degrees Turner acidity. If the acidity is above 20 degrees, then the milk begins to sour. The maximum acidity of milk is 20 degrees Turner.
Determination of cottage cheese acidity
Place 5 g of cottage cheese in a 150-200 ml beaker and add 50 ml of water heated to 30-40°C. The cottage cheese is thoroughly mixed with a glass rod. Then add 5 drops of an alcohol solution of phenolphthalein and pour in a 0.5-molar solution of sodium hydroxide from a burette until a permanent pink color is formed. The number of milliliters of added alkali is multiplied by 20. In this way, the acidity of the cottage cheese is determined in degrees according to Turner. The acidity of the highest grade cottage cheese is no more than 200 degrees. The acidity of the first grade of cottage cheese is no more than 220 degrees. The acidity of the second grade of cottage cheese is no more than 240 degrees.
The first part of the experiment is carried out 2-3 hours before the lesson. Casein is one of the proteins in milk; it is excreted in the form of a curd-like sediment. For the experiment, take 0.5 liters of milk. After the milk has stood for a long time, the cream is removed from its upper surface. Cream is the fat part of milk. Then add 10 ml of a 10% solution of hydrochloric acid and leave the liquid to stand for 2.5 hours. The resulting casein is squeezed through linen. To completely remove traces of acid, the protein is washed repeatedly with water.
Lesson experience
To remove traces of fat in casein, add 25 ml of water and heat for 10 minutes. Then the water is drained, the casein is squeezed out through a cloth and dried in an oven at a temperature of 60°C. After cooling, the casein is weighed.
Chief technologist. I ask all departments to report on how chemical research is progressing.
All departments report chemical testing performed.
Director of the dairy plant. It's nice to hear about the completion of your chemical research. And what are the results of your work? Who will speak out?
Laboratory of Organic Chemistry. We conducted a study on lactose content, i.e. milk sugar in milk. The determination showed a positive reaction to the lactose content in milk.
Director of the dairy plant. Thank you for your message. Who is next?
Laboratory of Analytical Chemistry. Our laboratory determined the acidity of milk. We determined that the milk sample under study contains 18 degrees Turner acidity. This means the milk is fresh.
Director of the dairy plant. The message is good, but what about the acidity of the curd under study? I'm waiting.
Laboratory of General Chemistry. We determined that the acidity of cottage cheese is 210 degrees. First grade cottage cheese.
Director of the dairy plant. It’s a pity, of course, that it’s first grade. I wanted the highest, but nothing can be done, the first is the first. So be it. Thank you all for your work. The meeting is over.
Final words from the teacher. So, dear guys, we conducted a lesson on the chemical determination of milk quality. You have learned to determine lactose in milk, the acidity of milk and cottage cheese, and the casein content of milk. I ask you to short form characterize the progress of chemical analysis.
Students talk about the progress of their research.
To summarize our lesson, in conclusion I can say the following about milk. Opinions about milk and its benefits are clearly divided: for and against. Many scientists and doctors consider milk to be harmful, but at the same time beneficial. It is impossible to draw a line between the harmful and healing properties of milk. Yes, it harms some people, helps others. Like all medicines, so are food products: some are well absorbed, others are poorly absorbed or not absorbed at all. Each body reacts differently. On the pages of many publications there was controversy about the properties of milk. But it is impossible to say specifically for or against. Everyone has their own opinion. IN difficult years Many survived their lives only thanks to this food product, having their own household. So, I think it is premature to completely exclude milk from your diet, but you can limit it in your diet. Each food product in large quantities is a slow-acting poison, and when used in moderation, it is a stimulant of living space. Today you have seen for yourself how many vitamins and valuable elements and substances for life are contained in milk. And regarding environmental assessment, it can be noted that now there is not a single food product that is ideally environmentally friendly. This is an indisputable factor; it can always be proven by the most accurate chemical and analytical studies.
If you feel and believe that milk benefits you and strengthens your body, then drink it for your health, as much as you think it is possible to drink it. And may it give you strength, health, vigor and energy throughout your working day and throughout your life! Drink milk and pay less attention to everything!
Unlike other types of milk, breast milk contains 7% carbohydrates (lactose), lactase - an enzyme that digests lactose, 4% fat, lipase - an enzyme that breaks down fats, polyunsaturated fatty acids, essential amino acids, vitamins "C", "B", “K”, “D”, water – 87%, protein hormone – adiponectin, casein – beta, lactalbumin, macroelements – calcium, phosphorus, sodium salts, microelements – iron, etc. A simple protein is a - lactoglobulin, cystine, taurine, thyroxine, antibacterial proteins - lactoferin, lysozyme.
The horse was domesticated about 6000 years ago, the donkey - 5000 years ago, buffalos - no later than 3000 BC, the cow - about 6000 years ago, the goat, camel, sheep - about 3500 - 7000 years ago.
Stages and prospects for the development of milk chemistry and physics. The role of domestic scientists in the development of chemistry and physics of milk. Chemistry, physics (and biochemistry) of milk as a science was created in the 20s…30s of the 20th century. Professor G. S. Inikhov and Professor Ya. S. Zaikovsky and continued by other scientists (P. F. Dyachenko, A. I. Ovchinnikov, A. P. Belousoa, I. I. Klimovsky, etc.)
Georgy Sergeevich Inikhov (1886-1969).
Professor G.S. Inikhov devoted almost 60 years of his life to the formation of the national school of chemistry and biochemistry of milk and dairy products.
G. S. Inikhov in 1910, graduated from the Faculty of Physics and Mathematics of St. Petersburg University. Since his student days, he linked his fate with the dairy industry - his diploma work on the topic “Chemical composition and properties of milk from Yaroslavl cows” was awarded a 1st degree diploma.
After graduating from the university, Georgy Sergeevich went to the city of Kurgan - a large butter-making center Western Siberia, where he began to manage the dairy testing laboratory.
Here he studied the physicochemical numbers of milk fat and the influence of various factors on them, and developed a method for controlling the moisture content in butter.
In 1916, he was invited to the Vologda Dairy Institute to the position of head of the experimental biochemical station, soon he was elected professor of the department of “Biochemistry of Milk and Dairy Products”, and then in 1924 (to 1930) - rector of the institute.
In 1917, G.S. Inikhov developed a method for producing rennet, which had previously been imported from abroad; later, according to his plan, a rennet plant was built in Moscow. He devoted a lot of time to studying the mechanism of action of rennet on milk casein and the influence of temperature, calcium salts, milk acidity and other factors on its activity. By this time, Georgy Sergeevich became a well-known specialist in the field of biochemistry of milk and dairy products.
In 1922-1924. he wrote and published the world's first textbooks, “Chemistry of Milk and Dairy Products” (for universities) and “Analysis of Milk and Dairy Products.” 13 1934 he published “Biochemistry of Milk” for food universities and in 1956 for universities of the dairy industry “Biochemistry of Milk and Dairy Products” for technical schools was published by him in 1935 (and republished in 1951, 1962 and 1970 G.). Together with N. G1. Brio he wrote the reference manual “Methods of Analysis of Milk and Dairy Products”. Thousands of students throughout the country were then taught using his textbooks, and more than one generation of dairy industry specialists studied using them.
In 1930 G. S. Inikhov headed scientific work All-Union Scientific Research Institute of the Dairy Industry and continues to be active pedagogical activity- Heads the department and teaches the course “Biochemistry of Milk” at the Moscow Institute of Dairy Engineers. From 1941 to 1952, G. S. Inikhov headed the department of organic chemistry and milk chemistry at the Moscow Technological Institute of Meat and Dairy Industry, where until 1965 he continued to teach the course “Biochemistry of Milk”; G. S. Inikhov participated in many congresses and conferences dairy industry, was a member National Committee USSR on dairy business, as well as scientific councils of a number of institutes.
Janusz Stanislavovich Zaikovsky (1887-1952). Professor Ya. S. Zaikovsky is a prominent scientist and talented teacher, who devoted 40 years of his life to serving the dairy industry and agriculture.
Ya. S. Zaikovsky graduated from the chemical-technological department of the Lvov Polytechnic Institute in 1912 and went to work at the Agronomy Academy as an assistant in the department of general chemistry. In 1914 he was awarded the academic degree of Doctor of Chemical Sciences
He began his research activities in 1918 at the experimental biochemical station of the Vologda Dairy Institute. Here in 1921 he was elected professor of the department of analytical chemistry. He directs all his creative energy to researching the nature of the influence of chymosin (rennet) on milk proteins.
In 1924, Ya. S. Zaikovsky went to work at the Leningrad Agricultural Institute. At the Children's Rural Zootechnical Experimental Station he studies mineral metabolism in the body of farm animals.
In 1925 he was approved as a professor of inorganic chemistry at the Omsk Institute Agriculture and forestry. The zootechnical laboratory he organized carried out extensive work on the study of feed and its effect on the composition of milk. In 1930, it was reorganized into the Department of Biochemistry and Milk Chemistry, which he headed until last days life.
For forty years scientific activity in the field of biochemistry and milk chemistry, Ya. S. Zaikovsky published sixty works that have important scientific and practical significance. He paid much attention to the study of coagulation and the properties of milk casein, developed his own theory (the “foam” theory) of butter formation, studied the mechanism of acid and rennet coagulation of casein in the production of cheese, and also worked on the basics of the production of canned milk. In addition, he developed a number of new methods for studying milk.
Y. S. Zaikovsky
The work of Ya became widely known. S. Zaikovsky - “Chemistry and Physics of Milk and Dairy Products”, which he republished twice (in 1938 and 1950). He based the book on the material of lectures that he gave for a number of years to students of the dairy industry department of the Omsk Agricultural Institute (now Omsk State Agrarian University).
Pavel Fedorovich Dyachenko (1905-1995) worked for many years at VNIMI, then at the Moscow Technological Institute of Meat and Dairy Industry (currently MGUPB),
During his long life, P. F. Dyachenko did a lot in the field of milk protein chemistry (“Study of milk proteins”, 1959; “Theory of phosphoamidase action of rennet”, 1961; “Study of the composition of the caseinate calcium phosphate complex of milk”, 1968 and etc.). He developed a technology for producing caseinates, thermocalcium co-precipitate and other protein products, a method for determining the buffer capacity of milk, etc. He is one of the authors of the textbook for universities “Technology of Milk and Dairy Products”, 1974.
Andrey Ignatievich Ovchinnikov (1907-196U) first worked at the Leningrad Institute of Dairy Industry Engineers, then at the Leningrad Institute of Refrigeration Industry (now St. Petersburg State Unitary Enterprise and Technology). They wrote more than 20 scientific articles(“To the effect of othermal coagulation of casein”, “A simplified method for determining calcium in milk”, “The influence of calcium on the consistency of cheese”, etc.).
Alexander Pavlovich Belousov (1900-1989) worked fruitfully both in the field of cheese making and butter making.
The pinnacle of his creativity should be considered his writing of the fundamental monograph “Physico-chemical processes in the production of butter by churning cream” (1984), Irinei Ivanovich Klimovsky (1903-1996). He devoted all his love and creative activity to cheese making. His monograph “Biochemical and microbiological foundations of cheese production” (1966) is widely known.
Huge contribution A. I. Chebotarev (1904-1991), Z. Kh. Dilanyan (1903-1994), D. A. Panikov (1902-1965) and N. contributed to the development of the chemistry and physics of milk. N. Lipatov (1923-1994) and other scientists.
Currently, enormous research work in the field of milk chemistry and physics is being carried out by teams of employees from numerous universities (Moscow, St. Petersburg, Vologda, Stavropol, Omsk, etc.).
Nutritional value of milk and dairy products.
Their role in human nutrition. Among the huge number of products of animal and plant origin, the most nutritionally valuable are milk and dairy products. “Among the varieties of human food,” wrote the great scientist Ivan Petrovich Pavlov, “milk is in an exceptional position... How amazingly food prepared by nature itself stands out from a number of other varieties.”
The high nutritional value of milk lies in the fact. that it contains all the nutrients necessary for humans (proteins, lipids, carbohydrates, minerals, vitamins, etc.) in well-balanced proportions and in an easily digestible form.
As you know, animal proteins play an important role in human nutrition. It is precisely the deficiency of complete animal proteins that is associated with the decline in health indicators of the population of many countries - their physical and mental development, resistance negative impacts, ability to work, life expectancy, etc.
Based on the content of essential amino acids and digestibility by proteases in the gastrointestinal tract, milk proteins are proteins of high biological value. At the same time, the nutritional value of casein is somewhat limited by the deficiency of the sulfur-containing amino acid cystine (the amino acid score of methionine in total with cystine is slightly below 100%). However, whey proteins have a better balance of deficient sulfur-containing and other essential amino acids than casein, and therefore their nutritional value is higher. Therefore, adding milk proteins in the form of protein concentrates to plant proteins containing insufficient amounts of lysine and tryptophan improves their amino acid composition.
It should be noted that milk proteins have a number of important functional properties that allow their concentrates to be used as valuable components of a variety of combined food products. These include their high water-binding capacity, viscosity, gelation, emulsification, tar formation and a number of others.
Functional milk proteins include acid casein, sodium, potassium and citrate casenates, condensates, and whey protein concentrates. All of them are widely used in the meat and dairy, baking and other sectors of the food industry as protein additives and structure stabilizers (production of processed cheeses, sour cream, yogurt, children's dairy products, puddings, creams, bread, pasta and meat products). All this makes it possible to improve the quality and biological value of traditional products and create fundamentally new types of food products.
At the same time, when there is a shortage of animal proteins, soy protein products are now widely used. Combined milk and protein products using a soy base (kefir, cottage cheese, curd pastes, various desserts, etc.) are recommended for nutrition for diabetics, patients with anemia, tuberculosis, stomach ulcers and other diseases.
IN last years There is increasing evidence that milk casein is a source of a number of biologically active peptides. These include gdicomacropep - tides cleaved from k-casein under the action of chymosin and phospho-peptides obtained from 3-casein during digestion. They promote the formation of protein clots of a high degree of dispersion, and also exhibit antigastrinic activity, that is, the ability to inhibit gastric secretion (or have the opposite physiological effect). In addition, according to the assumption of academician. A. M. Ugolev and a number of foreign researchers, they can have an analgesic and sedative effect.
Milk fat and other milk lipids are of certain value in human nutrition. As is known, the biological value of fats is determined by the content of polyunsaturated fatty acids, melting point, digestibility, and the amount of vitamins A, O, E (as well as trans isomers of unsaturated fatty acids). Compared to animal fats, milk fat is better absorbed in the human body, since it has a low melting point (28...3СГС) and is in a finely dispersed form, its digestibility coefficient is 97...99 >7%. Compared to vegetable fats, it contains relatively few essential fatty acids. At the same time, the presence of deficient arachidonic acid, short-chain fatty acids, as well as significant amounts of phospholipids and vitamins A and O in milk fat increases its nutritional value.
In the last decade, the production of dairy products with a combined or mixed fat composition (butter, sour cream, ice cream, condensed milk, cottage cheese, processed cheese, etc.) began to develop in Russia, for the production of which vegetable fats are used. However, the quality and safety of dairy products with a combined fat phase, manufactured in our country or imported from abroad, are not always guaranteed. Unfortunately, in order to save money, manufacturers choose cheap vegetable oils (palm, rapeseed, etc.) or milk fat substitutes with a high content of trans fatty acids. Therefore, it is so necessary to develop precise methods for monitoring the adulteration of milk fat and determining the mass fraction of non-dairy fats in products with a mixed fat composition.
The nutritional value of milk, along with proteins and milk fat, is determined by lactose. One of the components of lactose - glucose - is a source of synthesis of the reserve carbohydrate of the newborn's body - glycogen, and the other component - galactose - is necessary for the formation of brain ganglycosides. It is necessary to note the valuable properties of lactose - the ability to improve the absorption of calcium by the human intestine. And finally, the enormous physiological role of the alkaline derivative of lactose, lactulose, which is recognized in the world as the main prebiotic used for functional nutrition, is very important.
As you know, functional food products are intended to restore normal human microflora, consisting of bifidobacteria and lactobacilli. which is able to resist colonization of the intestines by pathogenic microorganisms. It is the disruption of the normal intestinal microflora, or dysbacteriosis, accompanied by the production of toxic compounds (phenol, indole, skatole, etc.) by putrefactive microorganisms, which leads to various diseases and a decrease in human life expectancy. Consequently, the use of lactulose to fortify dairy products intended for feeding not only children, but also adults will help solve the problem of improving the health of the population of our country.
The nutritional value of milk and dairy products lies largely in their high content of calcium (in milk it is 120 mt%, in cottage cheese - 150, in hard cheeses - 850...1100 t%).
Calcium is an important component of human bone tissue and teeth, accounting for about 99% of all calcium intake. The rest of its quantity is found in cellular and tissue fluids, which is necessary for blood clotting, the mechanism of muscle contractions, the functioning of enzymes, etc. With insufficient intake of calcium into the human body, teeth are destroyed in children and rickets occurs, in adults - osteoporosis (demineralization of bone tissue). fabrics).
In cow's milk, calcium is well balanced with phosphorus, their ratio is 1:1... 1.3:1 (curd is 1:1.5...1:2). For adults, the Institute of Nutrition of the Russian Academy of Medical Sciences recommends their food ratio is 1:1.5, for children - 2.3:1.
As a rule, calcium supplied with food is almost insoluble in water and is poorly absorbed by the small intestine. The exception is calcium in milk and dairy products, since the processes of its absorption and assimilation are positively influenced by lactose, as well as its content in the phosphopeptidoa formed during the proteolytic breakdown of casein. Thus, the main part of calpium (about 75%) in the diet is covered precisely by milk, cottage cheese and cheeses.
At the same time, milk is relatively poor in magnesium and microelements - iron, iodine, selenium (sometimes zinc), which can lead to disruption of the heart muscles, anemia, physical and mental retardation in children, as well as cardiovascular diseases and immunodeficiency. Currently, attempts are being made to add calcium to milk (up to a level of 150 ... 180 mg%), as well as iron, iodine and selenium.
Milk and dairy products are a source of many vitamins for the body. Thus, 50...70% of human needs for riboflavin and 20...70% for cyanocobalamin are met by milk and fermented milk products, and butter and cheeses are the main supplier of vitamins A and O.
Thus, the nutritional value of milk is indisputable and it should be an indispensable food product for a person at all periods of his life. Various dairy products also play a very important role in nutrition - fermented milk drinks (yogurt, yogurt, kefir, etc.), cottage cheese, sour cream, cheeses, butter, etc.
Physiological norms for the consumption of milk and dairy products (in terms of milk), recommended by the Institute of Nutrition of the Russian Academy of Medical Sciences, are 1090 g per day and 392 kg per year.
According to the Department of Food and Processing Industry of the Ministry of Agriculture of the Russian Federation, actual consumption of milk and dairy products has decreased sharply in recent years. So, if in 1990 it was 386 kg per year, then in 1999 it was 206 kg or about 53% of the recommended norm. In 2000...2002 milk production per capita increased slightly and amounted to 222...228 kg. According to forecasts by the Russian Ministry of Agriculture, in 2005 it should be 270..310 kg, in 2010 - 343...386 kg.
Introduction
Chemistry and physics as a science began its countdown in the last century; during that period it began with the study chemical composition milk. In our country, this issue was dealt with by Ilyenko (1819-1877), then Kalantar (1859-1937). Milk chemistry (biochemistry) as a science was created in Soviet time Ave. Inikhov and Zaikovsky, who worked at the Vologda Dairy Plant, then at the Moscow Meat and Dairy Plant (MGUBT). In the 20-30s, they wrote the first textbooks on the biochemistry of milk (Milk Chemistry, Milk Analysis: Chemistry and Physics of Milk and Dairy Products). The great Russian scientists Pavlov and Mechnikov made a great contribution to the development of milk science.
A significant contribution to the development of milk biochemistry was made by Prof. Parashchuk (1873-1850); The development of biochemistry was facilitated by the work of Belousov, Brio, Granikov, Davidov, Dilanyan, Dyachenko, Kazansky, Klimovsky, Kovalenko, Ovchinnikov, Chebotarev and others.
Currently, research is being carried out by teams in the field of chemistry and physics of milk from VNIMI, the Uglich Research Institute and scientists from other higher educational institutions.
The subject “Chemistry and Physics of Milk” is based on the achievements of related sciences, such as organic chemistry, physical and colloid chemistry, physiology, and nutritional biochemistry. This science studies the chemical composition of milk, the physical and chemical properties of milk: density, acidity, thermophysical, optical, etc. As well as milk systems in which the components are located: this is the true solution phase, the colloidal phase, the emulsion phase. A special role is given to the study of changes in milk and its components during processing and processing. These are energy effects, mechanical loads, temperature effects, biochemical transformations. Without this knowledge, it is impossible to carry out technological processes for the production of milk and dairy products, because any changes to traditional production methods can affect the components of milk, which, in turn, will affect the quality of dairy products.
When using high-performance equipment, it is very important to preserve the properties of milk and its components. This is why dairy technology must have extensive knowledge of chemical, biochemical and physical properties components of milk.
MILK - complete and useful product nutrition. It contains all the nutrients necessary for life that are needed to build the body. The natural purpose of milk in nature is to provide nutrition to the young body after birth. The composition of the milk of various mammals is generally determined by the conditions environment, in which the growth of a young organism occurs. This is especially clearly manifested in the content of protein and fat; the more of them in a mother’s milk, the faster her child grows.
Thus, an infant doubles its weight in about 180 days, a calf in 50 days, and a puppy in 9 days. The protein content in human milk, compared to the milk of various animals, is the lowest - 1.6%, in cow's milk - 3.4%, and in dog milk - 7.3% protein. Milk fat serves primarily to satisfy the body's energy needs. In areas with cold climates, the body's need for energy is higher than in areas with temperate climate. This is why the milk of a female reindeer has a higher fat content - 19.7%.
Milk survived many civilizations before it became a food product and has its own purpose:
As a food product for the population;
Means for feeding young animals and feed in livestock farming;
Raw materials for food production;
a source of individual milk components, which, in turn, serve as raw materials for pharmacology and other industries.
The increasing importance of milk as a complete food product and as a raw material has led to an increase in demand for it. As a result, milk production has become one of the most important sectors of agricultural production. Currently, milk makes up a significant share of our country's gross agricultural product.
The nutritional value of 1 liter of milk is 685 kcal. Calorie content depends mainly on the fat and protein content. Due to the content in milk of the most important nutrients, mainly protein, carbohydrates, vitamins, minerals, it is also a protective factor. In order to protect health in enterprises where hazardous working conditions exist, workers receive milk.
Milk protein is an important protective fact because... due to its alephotheric nature, it binds vapors of acids and alkalis, and also neutralizes toxic heavy metals(traces) and other substances harmful to health. Due to the content of calcium, phosphorus, and vitamins in milk, the development of vitamin deficiencies is prevented. In addition to human nutrition, milk is used to feed farm animals: calves, pigs, birds.
Using physical and biochemical methods, dairy products are obtained from raw milk, which are partially enriched food products, due to which these products are characterized by an increased calorie content for every 100 g. Processing of milk leads to a change in its nutritional value and taste, therefore it is necessary to take into account the properties of each a separate component of milk. The raw materials for industry are milk components such as casein and lactose. The substance of milk can be defined from various points of view, taking into account, first of all, the purpose of use. If we consider milk as a food product, then legislative, hygienic and economic requirements come to the fore, so we can define raw milk.
“Raw milk is the pure and then cooled product obtained as a result of regular, complete milking of the udder of one or more cows from one or more milkings, from which nothing has been removed or to which nothing has been added.”
Knowledge about the number of components of milk has constantly expanded over time. This can be explained by purposefulness scientific research and the use of modern methods of analysis, which make it possible, without using enrichment methods, to detect and quantify even those components of milk that are present in it in the form of traces. Currently, over 200 different components of milk are known.
Milk constituents are all those components that are released from the udder during milking.
Chemicalization of agriculture, treatment of diseases of cattle, as well as diseases of the udder with the help of chemotherapeutic agents have led to an increase in the content of foreign substances in milk, which enter it in various ways.
Purpose: to determine the biochemical value of milk
· Study the amino acid composition of milk
· Study the protein composition of milk
· Study the enzyme composition of milk
· Study the carbohydrate composition of milk
· Study the lipid composition of milk
· Study the vitamin composition of milk
· Study the elemental composition of milk
Determine practically the casein content in milk
Chemical composition of milk.
Cattle milk is a white opaque liquid with a yellowish tint, with a sweetish taste and peculiar odor. Milk plasma is a multicomponent system containing organic and mineral substances of varying degrees of dispersion. Protein-lipid complexes are present in milk in small particles called milk or fat globules. The size of fat globules can range from 0.5 to 18 microns.
The chemical composition of animal milk is very complex. Milk contains amino acids, proteins, carbohydrates, lipids, phosphatides, steroids, vitamins, enzymes, salts, gases, water, calcium.
There are fresh, whole and drinking milk.
Fresh milk is obtained immediately after milking cows. It has a temperature close to the body temperature of the animal. However, when standing, the temperature of the milk drops, and fat globules up to 1.5 microns in size float to the surface, forming a layer of cream. With a larger diameter, fat globules can form fat deposits. This type of milk is called whole milk.
Drinking milk is obtained by homogenization of whole milk, which is accompanied by fragmentation of milk fat globules, as well as an increase in the dispersion of protein particles. Homogenization of milk is carried out in order to improve appearance and taste, as well as increasing consistency and reducing raw material costs. In homogenized milk, aggregation of fat globules does not occur, since the aggregation mechanism is due to the occurrence of weak intermolecular interactions between amino acid residues and surface proteins of fat globules, which are destroyed during homogenization of milk.
After water and lipids are removed from milk, dry skimmed milk residue is formed, which is used as an indicator of milk quality.
Milk amino acids
Amino acids are low molecular weight organic compounds belonging to the group of carboxylic acids, which contain an amino group.
There are about 300 different amino acids found in nature. Proteins contain 20 types of amino acid residues, which are mainly present in milk. All of them belong to the α-L-forms of amino acids, in which the amino group is located in the α-position. According to their structure, these amino acids can be divided into three groups: hydrophobic (alanine, valine, leucine, isoleucine, phenylalanine, methionine, tryptophan, proline), polar uncharged (glycine, serine, threonine, tyrosine, cysteine, asparagine, glutamine) and charged (lysine, histidine, arginine, aspartic and glutamic acids). Of these, eight amino acids are not synthesized in the body of some animals and humans and are therefore called essential (valine, leucine, isoleucine, phenylalanine, tryptophan, methionine, threonine, lysine), two amino acids, although formed in the body, are in insufficient quantities (arginine, histidine ). For animal proteins, the composition of essential amino acids may vary depending on the species.
Man's friend from the cradle, milk is a complete "comprehensive" food product. And it's not strange. After all, until a certain age, a person, like other mammals, consumes only milk, which is so necessary for the nutrition, growth and development of his body.
Milk- one of the most important food products for humans, especially children, pregnant and lactating women, and the elderly. Milk and dairy products add variety to the diet, improve taste, increase the nutritional value of our food and are of great dietary importance. Milk contains physiologically highly valuable proteins, highly digestible fat, minerals, especially calcium and a number of important vitamins.
Composition and properties of cow's milk
Very interesting features can be noted when considering the average chemical composition of animal milk. For example, few people know that in terms of calorie content (in kilocalories per kilogram), the first places are occupied by the milk of a female deer (2725 kilocalories) and a rabbit (1708 kilocalories); compare with cow's milk, which has 713 kilocalories.
The same picture emerges when comparing fat and protein content. A female deer's milk contains 22.5 percent fat, a rabbit's milk contains 10.5 percent, while a cow's milk contains 3.7 percent. Sheep milk also contains a lot of fat - 6.7 percent. The protein in the milk of a female deer is 10.3 percent, in the milk of a female rabbit it is 15.5 percent, and in cow's milk it is only 3.3 percent. However, in terms of the content of milk sugar - lactose - cow's milk (4.8 percent lactose) is not far behind the milk of mare (6.7 percent lactose) and donkey (6.2 percent lactose).
Despite the fact that cow's milk contains up to 87 percent water, the so-called wateriness is not felt in its taste, just as milk sugar is not felt. This is explained by the fact that water and milk sugar are associated with proteins, phosphatides and other substances. However, the taste of milk that is frozen and thawed after some time changes dramatically: it becomes watery and sweet in taste. This is explained by the fact that after thawing, part of the water does not bind to proteins and milk sugar, that is, it remains in a free state and can be tasted.
Milk fat consists of triglycerides, which are esters of glycerol and fatty acids. Milk fat is found in milk in the form of tiny fat globules, about 2 microns in size (1 micron is equal to 0.001 parts of a millimeter). Fat is the lightest component of milk; when whole milk settles, it is released on the surface, forming cream. Cow's milk proteins are mainly represented by three types: casein, albumin and globulin. Casein alone accounts for 82 percent. Casein is bound to calcium and phosphorus.
If part of the calcium is “split off” from casein, it precipitates in the form of a flaky clot. This is what happens in milk when a large amount of lactic acid is formed (as a result of the development of lactic acid bacteria), when casein precipitates and the milk curdles. Globulin in milk contains approximately 6 percent, and it is in a dissolved state. It is believed that globulin is the carrier of the antibiotic properties of milk. Albumin constitutes approximately 2 percent of milk proteins. The white sediment that remains on the walls and bottom of the container after boiling milk consists primarily of albumin. The more milk is boiled, the less valuable nutrients remain in it.
Milk proteins contain all the amino acids vital for humans. During the processing of milk into cheese and other fermented milk products, milk proteins undergo hydrolysis, that is, breakdown.
Milk sugar is what causes milk to taste sweet. With the development of lactic acid bacteria, milk sugar is converted into lactic acid, alcohol, esters, volatile acids and other compounds. Under the action of the enzyme lactase or strong solutions of organic acids, lactose is hydrolyzed, that is, it breaks down into monosaccharides - glucose and galactose.
Lactose plays important role in the production of fermented milk products. During the development of yeast, lactose also undergoes alcoholic fermentation, so part of it turns into alcohol. Typically, both of these types of fermentation - lactic acid and alcoholic - occur in parallel. The technology of very interesting and healthy drinks is based on them - kefir, kumiss, ayran. Fermentation leads to the formation of gases, in particular carbon dioxide, which is responsible for the formation of eyes in the cheese.
Among the mineral salts in milk there are salts of calcium, phosphorus, magnesium, iron, sodium, potassium, citric, hydrochloric acids and others. Calcium, phosphorus and magnesium are part of bones, teeth, in addition, magnesium affects the functioning of the heart, and phosphorus is integral part nerve tissue and brain cells. All these salts are in milk in an easily digestible form - no food substance transfers calcium and phosphorus to the body better than milk.
Among the trace elements found in milk: cobalt, copper, zinc, bromine, manganese, sulfur, fluorine, aluminum, lead, tin, titanium, vanadium, silver and others. Of course, their number amounts to hundred thousandths or even millionths of a percent. It would seem that substances in such insignificant quantities cannot be important, however, as we have already said, their absence or deficiency in food can cause various disturbances in the functioning of the body. 
Vitamins, the need for which is calculated in thousandths of a gram, are presented quite fully in milk. We can safely say that milk contains almost all fat-soluble and water-soluble vitamins known in nature. Vitamin A and carotene (provitamin A) are dissolved in the fat of milk, so they are absent in skim milk. The vitamin A content in milk is 30-40 gamma percent (gamma is a thousandth of a milligram). Summer and autumn milk contains 2-5 times more vitamin A than winter and spring milk. There is several times more vitamin D in summer milk than in winter milk. Milk contains approximately 90 gamma percent vitamin E, the amount of which does not change significantly throughout the year. Vitamin K in milk is 3-4 gamma percent.
Of the water-soluble vitamins in milk, there is vitamin B1, or thiamine, vitamin B2, or riboflavin, vitamin B6, or pyridoxine, vitamin B12, or cyanocobalamin. Vitamin C in milk contains 1000-1500 gamma percent. Winter milk contains less vitamin C than summer milk. Evening milk contains 15-20 percent more vitamin C than morning milk. But vitamin C is the least stable; it is easily oxidized by atmospheric oxygen and loses its properties. To preserve it longer, it is necessary to immediately cool the milk after milking to a temperature below 8 degrees and subsequently store it, without shaking, at a low temperature, avoiding light shining on the milk.
In addition, milk contains vitamin PP, or nicotinic acid, vitamin H, or biotin, folic acid, which is involved in hematopoiesis, pantothenic acid, which promotes the normal development of nervous and circulatory system And skin, and choline.
Milk enzymes play a very important role. Milk contains numerous enzymes, in particular hydrolyzing enzymes - galactase, lactase, lipase, phosphatase and redox enzymes. In early childhood, milk enzymes may be important for the processes of transformation of nutrients in the gastrointestinal tract. However, boiling milk destroys its enzymes.
An important role is played by the immune bodies contained in milk, which increase the body’s resistance to infectious diseases, which is especially important for children who have not had childhood illnesses.
About the milk of other animals
The population of various countries widely uses in their diet, in addition to cow's milk, the milk of other farm animals: goats, sheep, mares, donkeys, camels, and deer. 
Goat's milk is higher in biological value than cow's milk, since it contains more highly dispersed proteins, and when it coagulates, more delicate flakes are formed. It contains more cobalt salts, which is part of vitamin B12. There is a prejudice that when consuming goat milk, children develop anemia - this is completely unfounded.
Sheep milk is 1.5 times more nutritious than cow milk. There are 2-3 times more vitamins A, B1 and B2 in sheep's milk than in cow's milk. Sheep milk is widely used for making yogurt, kefir, cheese, butter and other products. Residents of Italy, Greece and the Middle East consume a lot of sheep and goat milk. The least fatty milk is mare's milk, but it contains many vitamins, especially vitamin C. It has great medicinal value and is used for the production of kumiss.
Donkey milk is close in composition and properties to human milk. Camel milk has a specific taste, which contains a lot of fat, phosphorus and calcium salts. In desert and semi-desert areas, the local population consumes camel milk fresh and prepares a nutritious, refreshing fermented milk product from it - shubat.
The most high-calorie milk known northern peoples- This is deer milk. It is four times more calorie than cow's. In India, Indonesia and Egypt, buffalo milk is consumed mainly. It is thicker than cow milk, twice as fat.
Variety of fermented milk products
There is a great variety of fermented milk products. Yogurt and Varenets in Russia, matsun in Armenia, matsoni in Georgia, katyk in Azerbaijan and Central Asia, chal in Turkmenistan, kurunga in Northeast Asia, jugurt, ayran and kefir in the North Caucasus, kumiss in Bashkiria, Kazakhstan, Tataria, fermented baked milk in Ukraine, leben in Egypt, yagurt (or yaurt) in Bulgaria, Romania, Turkey, Greece, funeral milk in Norway, etc.
What are the features national species curdled milk (sour milk)?
Ukrainian curdled milk, or ryazhenka, the taste and consistency resembles sour cream, and the sweetish aftertaste resembles stewed milk. The fat content of fermented baked milk is 6 percent. To prepare it, pure cultures of lactic acid streptococcus are used. The calorie content of fermented baked milk is significantly higher than the calorie content of yogurt of other varieties.
Varenets produced from baked or sterilized (steamed) milk. In this case, some evaporation of moisture from the milk and its thickening occurs. Varenets is thick, slightly viscous in consistency, and its sour taste has a sweetish aftertaste.
Matsoni, matsun, katyk- different names for the same type of southern sour milk produced from cow, buffalo, sheep or goat milk. The main microflora of these products is Bulgarian bacillus and heat-loving lactic acid streptococci. Milk is fermented at elevated temperatures (48-55 degrees) and fermented in a device that retains heat.
Dzhugurt produced in the North Caucasus (Kabardino-Balkaria). This is pressed sour milk that looks like thick sour cream or paste. It contains 12-13 percent fat, and no more than 70 percent water. Various dishes are prepared from this pressed sour milk. It can be stored for a long time for consumption in winter months in the form of a creamy product “brnats-matsun”.
Ayran- mixed liquid yogurt, which is prepared in household for future use For better storage, the whey is partially removed from the mixed curd and salted.
Yogurt, or yagurt, or yaurt, has become widespread in Europe and America. It has long been known in Bulgaria. In some countries, yogurt is made from partially evaporated milk or from whole milk to which powdered milk is added.
Shubat (in Kazakhstan), or chal (in Turkmenistan)- a highly foaming fermented milk drink with a pronounced sour-milk taste and yeasty smell made from camel milk. The initial starter for preparing the drink is sour camel milk - katyk.
Fermented milk drink kurunga common among the Buryats, Mongols, Tuvinians, Khakassians, Oirots, etc. It is a product of lactic acid and alcoholic fermentation, pleasant to the taste, and not much different in consistency from kumiss. Milk wine is obtained by distillation of kurungi. container -
sung and semi-liquid nutritional drink Arsu.
In addition to the mentioned drinks, other interesting things, not to mention ordinary yogurt, Mechnikovskaya yogurt(it differs from the ordinary one in its more sour taste and dense clot) and southern curdled milk(slightly viscous, with a pinching, refreshing taste).
MINISTRY OF EDUCATIONRUSSIAN FEDERATION
KEMEROVSK TECHNOLOGICAL INSTITUTE
FOOD INDUSTRY
T.A.OSTROUMOVA
CHEMISTRY AND PHYSICS OF MILK
animal origin as a teaching aid
for students of higher educational institutions studying
in direction 655900 – Technology of raw materials and products
animal origin by specialty
271100 – Technology of milk and dairy products
Kemerovo 2004
UDC: 637.1.
Published by decision of the Editorial and Publishing Council of the Kemerovo Technological Institute of Food Industry
Reviewers: Head of the Department of Food Technology, Altai State Technical University. I. I. Polzunova, Doctor of Technical Sciences, Professor M. P. Shchetinin
Director of the State Scientific Institution Siberian Research Institute of Cheese Making, Siberian Branch of the Russian Academy of Agricultural Sciences,
Doctor of Technical Sciences A. A. Mayorov
Ostroumova T. A.
Chemistry and physics of milk: Tutorial. -
Kemerovo Technological Institute of Food
industry. - Kemerovo, 2004.- 196 p.
ISBN 5-89289-250-6
The characteristics of milk components, their structure, composition, features of biosynthesis, physicochemical, chemical, organoleptic and technological properties are presented. The issues of equilibrium relationships between different phases of milk as a single polydisperse system are outlined. An analysis of changes in constituent components in the processes of obtaining, storing, transporting, processing milk and producing dairy products was carried out.
Intended for students of specialty 271100 – Technology of milk and dairy products.
Ill. - 12, table - 3, library title - 12
ISBN-5-89289-250-6 © Kemerovo Technological
Institute of Food Industry
ABOUT THE CHAPTER
Introduction……………………………………………………………. 6
Topic 1. The role of domestic scientists in the development of science
“Chemistry and physics of milk”……………………….. 7
Topic 2. Current state of the dairy industry
technology, the main directions of development of technology
logy of dairy products and research problems
knowledge in the field of chemistry and physics of milk………… 10
Topic 3. The role of milk and dairy products in nutrition
person. Economic aspects of rational
extensive use of milk in production
dairy products……………………………. 12
Topic 4. general characteristics chemical composition
milk…………………………………………. 15
4.1. General characteristics of the components
nents of milk……………………………. 15
4.2. Comparative assessment of the composition of cow milk
moat with milk from other agricultural
animals and with human milk……… 21
4.3. The influence of zootechnical factors on the sow
tav and properties of milk………………………. 26
Topic 5. Milk proteins…………………………………….. 34
5.1. Modern nomenclature of milk proteins.
Characteristics of casein and whey fractions
mouth proteins……………………………. 35
5.2. Protein structure…………………………… 45
5.3. Protein composition: elemental and amino acids
lot……………………………………………………….. 53
5.4. Physico-chemical properties of proteins……… 55
5.5. Chemical properties proteins………………. 62
5.6. Biosynthesis of proteins in the mammary gland……… 64
Topic 6. Milk lipids ………………………………….. 66
6.1. The importance of lipids. Classification………… 67
6.2. Glyceride composition of milk fat……… 69
6.3. Fatty acid composition of milk fat... 72
6.4. Physico-chemical properties of dairy
fat…………………………………………………………… 76
6.5. Chemical properties of milk fat……… 79
6.6. Phospholipids, sterols and other lipids…… 82
6.7. Biosynthesis of lipids…………………………….. 84
Topic 7. Milk carbohydrates……………………………………. 90
7.1. General characteristics of milk carbohydrates. Know-
lactose reading…………………………………… 90
7.2. Structure of lactose, its isomeric forms and
physical properties……………………………. 91
7.3. Chemical properties of lactose…………………. 95
7.4. Biosynthesis of lactose………………………………. 97
Topic 8. Minerals milk……………………… 98
8.1. General characteristics of mineral substances.
Salt composition of milk………………………….. 98
8.2. Salt balance of milk. Factors influencing
for salt balance……………………… 100
8.3. The role of macro- and microelements in milk and milk
local products………………………………… 103
Topic 9. Biologically active and other substances of milk... 106
9.1. Milk vitamins and their biological role……. 107
9.2. Characteristics of milk enzymes. Use
the use of enzyme properties in quality assessment
milk…………………………………………………………… 111
9.3. Hormones and gases…………………………………… 118
Topic 10. Milk as a polydisperse system………………. 120
10.1. General characteristics of disperse systems…… 120
10.2. Milk as a colloidal system………………. 122
10.2.1. The structure of casein micelles determines
defining the colloidal state of the sol…………….. 122
10.2.2. Conditions for destabilization of the colloidal system
melting of the sol and formation of a gel upon dis-
personal methods of coagulation…………… … 126
10.2.3. Co-precipitation of casein and whey
proteins during thermocalcium and thermo-
acid coagulation methods…………….. 130
10.3. Milk as an emulsion of fat in plasma…………… 131
10.3.1. Factors of aggregative stability of fat
howl of emulsion…………………………………… 131
10.3.2. Factors affecting fat stability
emulsions……………………………………….. 136
10.4. Milk as a true solution…………………. 140
Topic 11. Physico-chemical, organoleptic and technological
gical properties of milk…………………………… 143
11.1. Density………………………………………………………. 145
11.2. Titratable acidity………………………… 146
11.3. Active acidity and buffering properties... 147
11.4. Redox potential.. 151
11.5. Viscosity and surface tension………… 152
11.6. Osmotic pressure and temperature measured
knowledge…………………………………………………………….. 154
11.7. Electrical conductivity and thermophysical
properties…………………………………………. 155
11.8. Organoleptic properties………………….. 156
11.9. Technological properties………………….. 158
Topic 12. Physico-chemical changes in milk during its
storage and processing………………………………. 162
12.1. Changes during storage in low conditions
temperatures and transportation………………. 164
12.2. Changes due to mechanical influences... 166
12.3. Changes during heat treatment………….. 168
Topic 13. Physicochemical and biochemical changes
components of milk in the process of its transformation
boots and when storing dairy products………. 174
13.1. Changes in milk components
during thickening and drying………………………… 175
13.2. Biochemical changes in the constituent components
components of milk during its processing………. 178
13.2.1. Fermentation of milk sugar. Types of fermentation
nia……………………………………………………………… 178
13.2.2. The role of fermentation products in the formation
taste, aroma and consistency of dairy products
products……………………………………. 186
13.2.3. Proteolysis and formation of organoleptic
technical indicators…………………………… 189
13.2.4. Changes in lipid components………… 191
Bibliography……………………………………. 195
INTRODUCTION
“Chemistry and Physics of Milk” is a discipline of a special cycle that forms professional knowledge engineer-technologist of the dairy industry. Along with others, this discipline provides a theoretical basis for the study of the technology of milk and dairy products.
The purpose of this course is to master the basics of chemistry and physics of milk to the extent necessary to solve production problems of the industry and in research activities.
The main objectives of the course are the acquisition of theoretical knowledge, practical skills and abilities for their further use in professional activities: in analyzing the composition and properties of milk, choosing directions for their improvement and adjustment, choosing and justifying technological parameters for processing and processing milk, justifying the economic feasibility of using milk for the production of certain dairy products.
As a result of studying the discipline, you should know and be able to:
chemical composition, physicochemical and organoleptic properties of milk;
characteristics of milk components, their structure, composition, physicochemical properties that determine the nutritional, biological value and technological properties of milk as a raw material for the dairy industry;
methods for adjusting the composition of milk necessary in production conditions;
the influence of various factors: zootechnical and technological on the composition and properties of milk;
the role of milk and its individual components in ensuring rational human nutrition;
equilibrium relationships between different phases of milk as a single polydisperse system;
physicochemical changes in milk during its storage and processing;
physical and chemical processes in the production of various groups of dairy products;
theoretical foundations of methods for studying the composition and properties of milk;
apply theoretical knowledge in specific production situations;
conduct research on the composition and properties of milk;
theoretically justify the choice of technological parameters for milk processing and processing.
Topic 1. ROLE OF DOMESTIC SCIENTISTS IN THE DEVELOPMENT OF THE SCIENCE “CHEMISTRY AND PHYSICS OF MILK”
The formation of the science “Chemistry and Physics of Milk” is directly related to the organization of first handicraft and then industrial production of dairy products.
The organization of industrial production of dairy products dictated the need to develop theoretical knowledge in the field of the composition and properties of milk, scientific explanations and justifications of technological processes, as well as the training of professional personnel.
