Milk is a major source of dietary energy, protein and fat, contributing on average 134 kcal of energy/capita per day, 8 g of protein/capita per day and 7.3 g of fat/capita per day.
The inclusion of milk in the diet of a person and especially a child is directly related to a healthy life. Milk is directly related to maternal affection and care.
The nutritional value of milk is particularly high due to the balance of the nutrients that compose it. The composition varies among animal species and breeds within the same species, and also from one dairy to the other, depending on the period of lactation and diet.
The chemical composition of milk is influenced by various daily factors, such as the age of the animal, lactation (milking stages), reproduction, time of year, ambient temperature, diet, health status and gestation period of the animal.
Various species of animals are used to produce milk. Cow’s milk has the highest consumption. Its share in world milk production is 90%. They are followed by buffalo milk with 5%, goat milk with 3% and sheep milk with 2%.
For instance, goat milk is 88% water and 11.4% solids; it contains 3.2% fat and 8.13% of fat solids. It is also comprised of calcium (0.11%), phosphate (0.08%) and magnesium (0.21%).
In general, the gross composition of cow's milk in the U.S. is 87.7% water, 4.9% lactose (carbohydrate), 3.4% fat, 3.3% protein, and 0.7% minerals (referred to as ash).
The main carbohydrate is lactose, which is involved in the intestinal absorption of calcium, magnesium and phosphorus, and the utilization of vitamin D. Lactose also provides a ready source of energy for the neonate, providing 30 percent of the energy in bovine milk, nearly 40 percent in human milk and 53–66 percent in equine milks.
Milk also comprises functional elements, such as traces of vitamins, enzymes and dissolved gases, and contains dissolved salts, especially in the form of phosphates, nitrates and chlorides of calcium, magnesium, potassium and sodium.
It also contains dissolved gases (5% by volume), mainly carbon dioxide (CO2), nitrogen (N) and oxygen (O2).
Nutritional properties of fresh milk
