COW dairy cattle producing milk is a very dominant compared to other dairy cattle. Dairy cows are very efficient at converting forage in the form of concentrates and forages into milk that are beneficial to health. In developed countries, dairy cow population maintained in the highest, because it is one of the nation's economic powerhouse. Dairy cows produce milk with a perfect balance of nutrients that can not be replaced other foodstuffs.
The Director General of Animal Husbandry No. SK. 17 of 1983, explained the definition of cow's milk is milk that includes fresh milk, whole milk, pasteurized milk, and milk sterilization. Fresh milk is pure milk that does not have the heating process. Pure milk is the liquid that comes from healthy cows udder. Whole milk obtained by milking the correct way, without reducing or adding any other components or materials.
Biologically, milk is physiological glandular secretions udder as food and immunological protection (immunological protection) for baby mammals.
The history of human consumption of cow's milk was started thousands of years BC, when humans began to domesticate milk-producing livestock for consumption results. Areas that have a high civilization such as Mesopotamia, Egypt, India, and Greece alleged human origin region maintaining dairy cows first.
It is shown from the evidence of the remains of sculptured images of cows and the confidence of local communities who regard cows as sacred animals. At the same time milk has been processed into various products such as butter and cheese. Availability of milk in this modern age is the result of a combination of knowledge about milk that has been thousands of years old with the application of technology and modern science.
Prof. Douglas Goff, a dairy scientist at the University of Guelph, Canada stated, the composition of milk consists of water (water), milk fat (milk fat), and nonfat dry ingredients (nonfat solids). Then, nonfat dry material subdivided into protein, lactose, minerals, acids (citric, formic, acetic, lactic, oxalic), enzymes (peroxidase, catalase, pospatase, lipase), gases (oxygen, nitrogen), and vitamins (vitamin . A, vit. C, vit. D, thiamine, riboflavin). Percentage or amount of each component is highly variable due to factors influenced by various factors such as the (breed) of cattle.
Milk is a food that has a specific component such as milk fat, casein (milk protein), and lactose (milk carbohydrate).
Fat milk
Milk fat percentage varied between 2.4% - 5.5%. Milk fat consists of triglycerides, composed of one molecule of glycerol with three molecules of fatty acid (fatty acid) via ester bonds (ester bonds). Milk fatty acids derived from microbiological activity in the rumen (stomach ruminants) or from synthesis in secretory cells. Fatty acid hydrocarbon chains arranged and carboxyl group (carboxyl group). One example of milk fatty acids are butyric acid (butyric acid) in the form of short chain fatty acids (short chain fatty acids) which will cause the smell of rancid (rancid flavor) butyric acid in milk when it is separated from glycerol by lipase enzymes.
Milk fat are removed from the udder epithelial cells in the form of granules of fat (fat globule) whose diameter varies between 0.1 to 15 microns. Fat granules are composed of grains of triglycerides surrounded by a thin membrane known as the Fat Globule Membrane (FGM) or the membranes of milk fat granules. FGM is a major component of proteins and phospholipids (phospholipid). FGM is one of them function as stabilizers of milk fat droplets in the emulsion with dilute conditions (aqueous) of milk, because milk cow contains approximately 87% water.
Fat milk contains several bioactive components that can prevent cancer (anticancer potential), including conjugated linoleic acid (conjugated linoleic acid), sphingomyelin, butyric acid, ether lipids (ether lipids), b-carotene, vitamin A, and vitamin D. Although milk contains saturated fatty acids (saturated fatty acids) and trans fatty acids are associated with atherosclerosis and heart disease, but milk also contains oleic acid (oleic acid) which has a negative correlation with the disease. Fat milk contains essential fatty acids, linoleic acid (linoleic acid) and linolenic (linolenic acid) which has various functions in the metabolism and control a variety of physiological and biochemical processes in humans (D. Mc Donagh et al., 1999).
Milk protein
Protein in milk reached 3.25%. The primary structure of proteins consist of polypeptide chains of amino acids incorporated peptide bonds (peptide linkages). Some specific proteins make up a protein milk. Casein is the largest protein component in milk and the rest of whey protein. Casein in milk protein levels reached 80%. Casein consists of several fractions such as alpha-casein, betha-casein, and kappa-casein. Casein is one of the organic components are abundant in milk along with fat and lactose.
Casein consumed is important because it contains the amino acid composition of the body needs. In acidic conditions (low pH), casein will precipitate because it has a solubility (solubility) is low in acid conditions. Milk is an important food ingredient, because it contains casein which is also easily digested protein quality (digestible) digestive tract.
Acid casein (acid casein) is ideally used for medical, nutritional, and pharmaceutical products. Besides the food, acid casein is also used in paper coating industry (paper coating), paint, textile, adhesives, and cosmetics.
Heating, provision of proteolytic enzymes (rennin), and acidification can separate casein with whey protein. Moreover, centrifugation on milk can also be used to separate the casein. After the casein removed, then any remaining protein in milk called whey protein.
Whey protein is a protein granules (globular). Betha-lactoglobulin, alpha-lactalbumin, immunoglobulin (Ig), and Bovine Serum Albumin (BSA) is an example of whey protein. Alpha-lactalbumin is a protein important in the synthesis of lactose and its presence is also a principal in the synthesis of milk.
In the whey protein also contained several enzymes, hormones, antibodies, growth factors (growth factors), and the carrier of nutrients (nutrient transporter). Most of the whey proteins are less digested in the gut. When whey protein is not completely digested in the gut, then some intact proteins can stimulate a systemic immune reaction. This event is known as milk protein allergy (milk protein allergy).
Carbohydrate milk
Karbohirat is an organic substance consisting of carbon, hydrogen, and oxygen. Carbohydrates can be classified based on the number of molecules of simple sugars (simple sugars) in the carb. Monosaccharides, disaccharides, and polysaccharides are some groups of carbohydrates. Lactose is the main carbohydrate of milk with 4.6% proportion of total milk. Lactose is a disaccharide composed fall into two monosaccharides, namely glucose and galactose. The sweet taste of lactose is not as sweet as other disaccharides, such as sucrose. The sweet taste of lactose is only one-sixth times the sweetness of sucrose.
Lactose milk can affect the osmotic pressure, freezing point and boiling point. The presence of lactose in milk is one of the uniqueness of the milk itself, because the lactose is not present in nature except as a product of the mammary gland. Lactose is a food substance that provides energy for the body. However, it should be split lactose into glucose and galactose by an enzyme called lactase to be absorbed by the intestine.
Intestinal enzyme lactase is an enzyme that is used to absorb and digest lactose in milk. The enzyme is a substance that works as a catalyst for change chemically, with no intervening change in the enzyme itself. If the lack of enzyme lactase in the body, humans would experience indigestion when consuming dairy. Undigested lactose in the colon will accumulate and will affect the balance osmotis in it, so that water can enter the intestines. These events are commonly called lactose intolerance.
At the time of infancy, humans produce a lot of lactase enzyme to digest milk. However, the enzyme lactase is normally reduced at the present time which eventually led to humans are not able to digest lactose. This event usually occurs in someone who is not accustomed to eating fresh milk as part of the daily diet. As a result, when the adult does not have immunity to lactose, so that people will be afraid to consume fresh milk. This can be overcome by changing the milk into other products such as yogurt. In yogurt, the lactose is broken down into simpler with the help of bacteria. Lactose intolerance is caused by genetic influences as well.
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