Milk is a complex nutrient product derived from the secretion of the mammary glands that contains more than 100 substances found in solution, suspension or emulsion in water. Let’s discuss about the nutrition facts of milk in this article.
The name ‘milk’ without indication of the animal species from which it comes is reserved for cow’s milk. Discover in this article the composition of milk as well as the nutritional values of cow’s milk and human breast milk.
The Three Characteristic Phases of Milk
- Colloidal Phase: Casein, the main protein of milk, is associated with mineral salts (calcium, calcium phosphate, etc.) and is dispersed in the form of many suspended solid particles, too small to settle. These particles are called micelles, and their dispersion in milk is called colloidal suspension.
- Lipid Phase: Fats and vitamins soluble in dairy lipids meet in the form of emulsion. An emulsion is a liquid containing suspended fat cells.
- Aqueous Phase: Lactose( milk sugar), certain proteins (Serum Proteins), mineral salts and other substances are soluble and are completely dissolved in milk water.
Note: casein micelles and fat globules give milk most of its physical characteristics as well as the taste and smell of dairy products such as butter, cheese and yogurt.
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Composition of Cow’s Milk and Human Breast Milk
Let’s discuss about composition of the milk first after that we’ll see the nutritional value of it.
Carbohydrates from Milk
The main sugar or carbohydrate present in milk is lactose, a disaccharide composed of a glucose molecule and a galactose molecule. Its sweetening power is six times lower than that of sucrose. The concentration of lactose in milk is relatively constant, it turns around 5%. Breast milk of human origin contains more: about 6%.
Unlike the concentration of lipids in milk, the concentration of lactose is similar with all breeds of dairy cows and can not easily be changed by changing the feed of the cow. Other carbohydrates are found in lower concentrations: glucose (14 mg / 100 g) and galactose (12 mg / 100 g).
Lactose may be responsible for some intolerance.
The concentration of protein in milk varies between 3.0 to 4.0% (30 to 40 grams per liter). The percentage varies depending on the breed of the cow and is related to the amount of fat in the milk. There is a close relationship between the amount of fat and the amount of protein in milk. The higher the lipid level, the greater the amount of protein contained in the milk.
80% of dairy proteins are caseins, responsible for curd in the manufacture of cheeses, 19% are soluble proteins such as albumin and lactoglobulin and 1% are protein enzymes.
Fats or lipids make up 3.5 to 6.0% of milk, which varies depending on the breed and diet of the cow . For example, food rations that are too high in concentrates can be responsible for a drop in the percentage of fat from 2 to 2.5%.
Fats contained in milk consist of 98% triglycerides, 1% phospholipids and 1% sterols (cholesterol), tocopherol and fat-soluble viatines.
Milk contains about 65% saturated fatty acids, 30% monounsaturated fats (oleic acid) and 5% polyunsaturated fatty acids.
Nutrition Facts of Milk
Comparison of average nutritional facts and values between cow’s milk and human breast milk, per 100 gram of milk:
|Nutrients||Cow’s Milk||Human Breast Milk|
|Energy (in Kcal)||61.0||70,0|
Content of mineral salts and vitamins in cow’s milk (ug = 0.001 grams):
|Mineral Salts & Vitamins||mg/100ml|
Milk contains traces of other minerals such as cobalt, copper, manganese, molybdenum, zinc, selenium, iodine, etc…
Because of the above mentioned nutrition facts of milk, its called a complete food for mankind.