Nutritional properties of fresh milk

Milk can be defined as a whitish liquid containing milk proteins, fats, lactose, and various vitamins and minerals, produced by the mammary glands of all adult female mammals after childbirth and serves as food for their young.

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

Goat milk nutritional value

Although the date of first milking and milk utilization is unknown, the first deliberately soured goat milk probably was prepared before 2000 BC.

Goat’s milk is used for drinking and making cheese and yoghurt.

Goat milk differs from cow or human milk in higher digestibility, distinct alkalinity, higher buffering capacity and certain therapeutic values in human medicine and nutrition.

The chemical composition of goat milk varies with breed and other factors, but goat milk contains approximately 11-0-13.0 % total solids, 3.0-5.5 % fat, 2.9-4.6 % proteins, 3.8-5.1 % lactose and 0.69-0.81 % ash (mineral matter).

It is naturally homogenized, with smaller fat molecules evenly suspend throughout the milk.

Fat in goat milk is high of short chain and medium chain triglycerides therefore goat milk more rapidly digested than cow milk because lipase attacks ester linkages of short or medium chain fatty acids more easily than those of longer chains.

Goat milk contains slightly less total casein but higher non-protein nitrogen than the cow counterpart.

Milk from goats is also high in vitamin A and niacin. Goats milk is one of the best fluorine sources, nearly ten times higher than cow’s milk. Dietary fluorine helps build immunity, protect teeth, and strengthen bones; however, fluorine is lost in pasteurization.

Goat milk taste varies a great deal by bred, by feed stuffs, by stage of lactation, by the age of the milk and especially by the way it’s handled.

This milk may be the milk of choice for children who are allergic to cow’s milk. The difference in the proteins mean that goat’s milk doesn’t cause an allergic response.

Goat milk nutritional value

Protein in milk

The proteins of milk are of great importance in human nutrition and influence the behavior and properties of the dairy products containing them.

Milk contains a wide range of protein that provide protection against enteropathogens or are essential for the manufacture and characteristic nature do certain dairy products.

Milk proteins, because of high surface activity, rapidly adsorb at the oil-water interface, producing the surface layer that stabilize oil/fat droplets against flocculation or coalescence.

Milk contains a number of different proteins and can be classified to:
1. Casein
2. Whey proteins
3. Milk fat globule membrane
4. Minor proteins
5. Enzymes

Casein and whey are the two predominant types of protein found in milk.

Casein is a phosphoprotein, meaning that phosphate groups are attached to some of the amino acid side chains. Casein exists in milk as the calcium caseinate. This salt has a complex structure.

Whey is the liquid portion of milk, consisting primarily of 93% water, lactose, whey proteins (primarily lactalbumin and lactoglobulin).

Both casein and whey protein have been found to be increasingly important for physiological and biochemical functions that have crucial impacts on human metabolism and health.

Biological active peptides released from caseins and whey proteins contain 3 to 20 amino acids per molecule.

Researchers have demonstrated that these peptides posses very important biological functionalities, including antimicrobial, antihypertensive, anti oxidative, anticytotoxic, immunemodularity, opioid and mineral carrying activities.
Protein in milk