Cow milk: composition and properties. Ingredients of cow's milk - table

This product is familiar to every inhabitant of our planet. Traditionally, milk is used for food by children and adults. Scientists frighten us with arguments about its harmful properties, but fans of this product does not become less.

This is due to the fact that milk is unique in its composition and properties, a natural product. In addition, it is raw materials for the production of a huge number of food products, which we use with great pleasure and health benefits. Let's study in this article in more detail cow's milk, composition and its useful properties.

Milk - almost 90% water?

For many, this fact is surprising, but the milk really is 87.5% water. All other amazing and useful components are concentrated in 12.5% of dry matter. This was determined by standard drying the milk sample to constant weight at a temperature of 105 ° C. As a result of this process, the water is completely evaporated, and only dry substances remain.

But the liquid consistency of milk is due not to a large amount of water, but to the fact that all substances and compounds are in a dissolved state.

Milk is also characterized by the SOMO index (dry fat-free milk residue). This value is obtained if all milk and water is removed from the milk. This indicator is normally at least 9% and serves as an indicator of the quality of the natural product. Cow's milk, whose composition was depleted by dilution with water, will give the SOMO index much lower than the norm.

Is milk fat useful?

The milk fat content of cow's milk is 3.5% on average. This indicator is strictly controlled by farmers and receivers of raw materials in factories. It is this characteristic that affects the quality of products: sour cream, cream, cottage cheese.

The composition of milk fat includes about 20 fatty acids. It is characterized by a low melting point (25-30 ° C) and freezing (17-28 ° C). The peculiarity of this fat is its shallow teardrop-shaped structure in the composition of milk. This causes its high percentage (about 95%) of assimilation by the human body.

Due to the low specific gravity, milk fat rises to the surface with the formation of a layer of cream. This valuable product is loved by many, and contains a lot of useful fat-soluble vitamins: D, A, K and E. Therefore, the consumption of milk with natural fat content enriches the body with biologically active substances and has a beneficial effect on human health.

What is the peculiarity of milk proteins?

Cow's milk, whose composition includes proteins in the amount of 3.2%, is considered a valuable nutritious product. This indicator is strictly monitored by farmers and enterprises of the relevant industry.

The milk protein is perfectly absorbed by the human body - more than 95%. Its peculiarity is in the content of essential amino acids, the deficiency of which leads to the disruption of metabolic processes. These include the following:

• Methionine - metabolizes fats, preventing liver dystrophy.
• Tryptophan is the starting material for the synthesis of serotonin and nicotinic acid. Its deficiency can lead to dementia, diabetes, tuberculosis and cancer.
• Lysine promotes normal hematopoiesis. Its deficiency is capable of provoking anemia, disturbances in the exchange of nitrogenous substances and calcification of bones, muscular dystrophy, failure of the liver and lungs.

In general, the milk protein consists of casein. It is presented in two forms: the alpha-variant causes an allergy in some people, the beta-form is perceived by the person well.

Serum or sulfamide proteins, whose content in milk is 0.6%, is a valuable nutrient and is widely used in the food industry.

In milk there is a microflora from the smallest organisms, which in the process of vital activity secrete special protein substances - enzymes, or enzymes. These structures regulate the chemical processes in the product and the effect of each of them is strictly specific. The activity of enzymes depends on the pH and temperature of the medium. Some of them help to assess the quality of milk:

• Lipase promotes the breakdown of fats into free fatty acids and glycerol. This changes the taste of milk for the worse, reducing its quality. The abundance of free fatty acids and their oxidation leads to rancidity of the product.
• Peroxidase - a thermoactive enzyme, serves as an indicator that the milk was pasteurized at 80 ° C.
• Catalase cleaves hydrogen peroxide up to water and oxygen. In milk from sick cows, the level of catalase is quite high.
• Phosphatase cleaves esters up to phosphoric acid and alcohols and is destroyed by ordinary pasteurization. Its absence serves as a confirmation of the pasteurization normally carried out.

Milk sugar and its transformations

The chemical composition of cow's milk includes a special compound - lactose, or milk sugar. For the human body, this component serves as an energy source. The lactase enzyme cleaves lactose to glucose and galactose.

Milk sugar helps to suppress the activity of pathogenic putrefactive microflora. Lactose has a beneficial effect on the nervous and cardiovascular activity of the human body.

Some people have a problem of rejection of milk sugar, called lactase deficiency. This ailment can be congenital or develops over the years. The cause may be a transferred disease of the digestive tract or a prolonged abstinence from drinking milk.

Microorganisms produce, as already mentioned, a special enzyme - lactase, which breaks down the milk sugar with the formation of more simple compounds: glucose and galactose. The first of these substances is a favorite food for most bacteria. Here's what happens with glucose, which is part of cow's milk: microorganisms ferment it, releasing lactic acid, alcohol and carbon dioxide. In the human intestine, as a result of this transformation, a weakly acidic medium is created, which has a beneficial effect on the development of a useful acidophilic microflora. The activity of decay bacteria is suppressed.

Mineral substances of milk

Cow milk, the composition of which includes organic and mineral components, is a source of valuable nutrients for the human body. Its peculiarity is that the mutual action of substances leads to their best assimilation. The following macronutrients can be distinguished in milk composition:

• Calcium - is present in easily digestible form and in balance with phosphorus. It is in the form of ions (10%), in the form of phosphates and citrates (68%), in combination with casein (22%). The total content of this element in milk is 100-140 mg, and in summer this figure is lower.
• Phosphorus , the content of which varies between 74-130 mg, is present in two forms. It is part of inorganic compounds in the form of calcium phosphates and other metals. Also, phosphorus is included in organic substances - esters, casein, phospholipids, enzymes, nucleic acids.
• Magnesium , the content of which is in the range of 12-14 mg, has a beneficial effect on the nervous, digestive and reproductive function of a person, increases immunity.
• Potassium (135-170 mg) and sodium (30-77 mg) support osmosis and buffering of all liquid media of the human body. They increase the solubility of many mineral compounds and acids, casein micelles;
• Chlorine (90-120 mg) is an indicator of the health of the animal. Increasing its concentration by 30% indicates the presence of mastitis in the cow.

In the milk is also a large number of trace elements. Despite the fact that their content is very small, these substances have a huge impact on the normal functioning of the human body. Milk contains iron, copper, zinc, manganese, iodine, molybdenum, fluorine, aluminum, silicon, selenium, tin, chromium, lead. All of them provide physiological processes in the human body.

Milk composition table

Indicators of the components of milk can vary. These data are influenced by the breed of cows, the quality of feed, the time of year and much more. But the average composition of cow's milk, the table of which is given below, amounts to the following indicators:

Useful and harmful microcomponents of milk

The composition of whole cow milk also includes vitamins, enzymes and pigments. Their content is measured by hundredths and thousandths of percent, but the value of these substances is very high. They have great biological activity, and even a very small amount of their presence is important for the human body.

At present, about 50 vitamins are found in milk, among which there are water-soluble - B1, B2, C - and fat-soluble - A, D, E, K. The presence of these biologically active components causes milk for human health, because their influence on physiology It is difficult to overestimate.

But the composition of this product may include substances that are capable of harming the body. Their content is also very small, but even these small doses can cause great damage to human health. These include:

• Toxic elements: arsenic (not more than 0.05 mg / kg), lead (not more than 0.1 mg / kg), mercury (0.005 mg / kg), cadmium (0.03 mg / kg).

They can get into the milk with feed or with a container. Their number is strictly rationed and controlled.

• Mycotoxins, in particular aflatoxin M1, are highly toxic products of mold fungi with a pronounced carcinogenic effect. It enters the milk together with the food, it is not eliminated by pasteurization. Its content is strictly normalized beyond 0.0005 mg / l.
• Antibiotics - tetracyclines, penicillins, levomycetin, streptomycin.
• Inhibitors - soda and other detergents and disinfectants.
• Pesticides and radionuclides (strontium-90, cesium-137) - together with fodder.
• Hormones in the form of estrogen are contained in fresh milk. Therefore, to avoid hormonal disorders, this type of product is not recommended for children.
• Various pathogenic and conditionally pathogenic microorganisms.

Thus, cow milk, the composition and properties of which directly depend on the nutrition and conditions of the animals, can not only benefit, but also harm. When buying this product, you should trust industrial companies that have proven themselves in the market. As a rule, such milk passes laboratory tests at all stages of the technological process, and the content of all useful and harmful substances in it is strictly controlled. A product purchased from a private trader in a spontaneous market is a mystery, both for the seller and the buyer. Do not risk your own health by succumbing to a tempting appeal to buy "real home-made milk."

What is remarkable about goat's milk?

Some people at the moment prefer kozemu milk. They explain this by having the product obvious pluses. The composition of goat and cow's milk is indeed somewhat different. Here are some facts confirming the difference between these two products:

• The content of cobalt in goat milk exceeds the same figure in the cow's product by 6 times.
• In goat milk, there is practically no alpha-1S-casein, which gives it the status of a hypoallergenic product.
• The lactose content in goat's milk is less than in cow milk, by 53%. This fact makes it easy to digest by people with lactose insufficiency.
• The fat content of goat milk is 4.4%, with 69% of acids being polyunsaturated and fighting cholesterol.
• In goat's milk is much less pathogenic microorganisms.

Which milk is better?

What kind of milk to eat - cow or goat - you decide. Both products are worthy of respect and are rightfully considered valuable and healthy. The main thing is to remember about safety and not to buy goods of questionable quality. Do not be tempted to try the fresh milk from the market. It can contain many pathogenic bacteria and toxic substances. It is best to buy the past due control and certification. Thus, you can protect yourself and your family from the threat that it is simply impossible to appreciate with the naked eye. Drink quality milk with pleasure!