Products
Milk is available in grocery stores in several varieties. These include whole milk with at least 3.5% fat, semi-skimmed milk (milk drink, with less fat), skim milk (virtually fat-free) and lactose-free milk with no lactose.
Structure and properties
Milk is a liquid secretion secreted by the mammary glands of female mammals and used to feed the young. Commercially available milk usually comes from cows. In addition, goat’s, buffalo’s and sheep’s milk and products made from them are also sold, among others. Milk is obtained by manual or machine milking. It is an oil-in-water emulsion of fat particles in water with a white color. Phospholipids and proteins act as emulsifiers. If the milk becomes bad (acidic) or comes into contact with acids, the emulsion falls apart and the milk flocculates. Ingredients in standardized (adjusted) and homogenized whole milk include:
- Water (87.2%)
- Milk fat (3.5% or higher): triglycerides with saturated and unsaturated fatty acids, cholesterol.
- Proteins (milk protein, 3.2%): casein, lactalbumin, lactoglobulin.
- Carbohydrates (4.9%): lactose
- Minerals: for example, calcium (120 mg in 100 ml).
- Vitamins: for example, vitamin D, vitamin A, B-complex
- Enzymes
- Bacteria such as lactobacilli
Milk has a relatively low calorific value of 65 kcal per 100 ml due to its high water content. Raw milk is a fresh milk that has not been heated above 40 ° C.. It is made durable, consumable and sterile or aseptic by heating (pasteurization). Pasteurized milk is stored in the refrigerator. UHT milk that has been highly heated can be stored unopened at room temperature.
Effects
Milk is a drink specially adapted to the needs of young animals and contains all the components necessary for the structure and growth of the organism. It is a supplier of important nutrients, minerals and vitamins.
Fields of application
- As a beverage and food.
- As a source of calcium and vitamin D.
- For the production of processed foods, usually in the form of milk powder – for example, chocolate.
- Milk is used to make a wide variety of dairy products. These include butter, cheese, cream, yogurt, curd and whey.
Contraindications
Milk should not be taken in case of cow’s milk allergy and not in large quantities in case of lactose intolerance. During pregnancy, raw milk and products made from it should not be consumed. Infants do not tolerate cow’s milk in the first year, because its composition is different from breast milk. Adapted infant milk is available for them.
Adverse effects
In lactose intolerance, the lactose in milk cannot be digested properly, leading to gastrointestinal symptoms. Milk can cause allergic reactions in sensitive people. Raw milk may contain infectious bacteria such as listeria. Therefore, it must always be heated before drinking.