Dairy science (assignment)

CHAPTER I

INTRODUCTION

1.1  Background

Cattle is the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos Primigenius. Cattle were originally identified as three separate species: Bos taurus, the European or "taurine" cattle (including similar types from Africa and Asia); Bos indicus, the zebu; and the extinct Bos primigenius, the aurochs. The aurochs is ancestral to both zebu and taurine cattle. Recently these three have increasingly been grouped as one species, with Bos primigenius taurus, Bos primigenius indicus and Bos primigenius primigenius as the subspecies. Significantly, the sequences of scientific classification for cattle are Kingdom: Animalia, Phylum: Chordata, Class: Mammalia, Subclass: Theria, Order: Artiodactyla, Family: Bovidae, Subfamily: Bovinae, Genus: Bos, Species: Bos primigenius taurus, Bos primigenius indicus or synonyms are Bos Taurus and Bos indicus.

 Based on the function, cattle divided into two types, dairy cattle and beef cattle. Dairy cattle are kept and raised specially for milk production. Many types of cattle are used for milk such as, Holstein, Australian Illawarra, Ayrshire, Jersey, and Brown Swiss. Beef cattle are bred and raised specifically to provide meat or beef. Steers are the best type for this purpose because they can be kept in herds without fighting each other. Heifers are also often used for beef, especially those that are not suitable to be used in a breeding herd. The cows of beef cattle are used to give birth to and raise calves for meat. The meat from a calf is called veal and from an older beast, beef. Beef cattle are often allowed graze over large areas because they do not have to be brought in every day like dairy cattle. The biggest farms in the world are cattle stations in Australia, ranches in North America and ranchos in Latin America where they run beef cattle. Many types of beef cattle such as Hereford, Angus, Red Angus, Shorthorn, Brahman, Limousin, Simmental, and Texas Longhorn. In Indonesian the kind of beef cattle such as Madura cattle and Bali cattle.

Milk is one of cattle product which has virtue effect for body healthy. Milk protein is clearly very important for the human body, but the calf is also need at certain age. Milk contains proteins called immunoglobulins that are one of the calf’s principal defenses against infectious organisms. Concentrations of immunoglobulins are especially high in the colostrum, the milk produced immediately at the onset of lactation.  Colostrum should be given to the calf as soon after birth as possible. This will at least double the young calf’s chances for survival. Colostral immunoglobulins are stable in the calf’s bloodstream for 60 days, providing protection until its own immune system is functional. Colostrum can be frozen and stored for administration to other calves, because the human cannot to consume it. That's the fact of the importance of milk protein for a calf. Then how the importance of milk protein for humans? So, in this paper will be explained about benefits of protein in cow's milk for humans.

1.2  Problem

The problem of this paper is:

a.    What the primary protein in cow’s milk?

b.    What the benefits of protein in cow’s milk for the humans? 

1.3  Objective

The objective of this paper is:

a.    To know the kind of primary protein in cow’s milk.

b.    To know the benefits of protein in cow’s milk for the human.

CHAPTER II

DISCUSSION

2.1  The Primary Protein in Cow’s Milk

Most of the nitrogen in the milk is found in the form of protein. The building blocks of all proteins are the amino acids. There are 20 amino acids that are commonly found in proteins. The order of the amino acids in a protein, which is determined by the genetic code, gives the protein a unique conformation. In turn, the spatial conformation of the protein gives it a specific function. There is a close relationship between the amount of fat and the amount of protein in milk, the higher the fat, the higher the protein. The primary protein divided into two major groups: caseins (80%) and whey proteins (20%). Historically, this classification followed the process of cheese making, which consists of separating the casein curd from the whey after the milk has clotted under the action of rennin or rennet (a digestive enzyme collected from the stomach of calves).

2.1.1     Casein

         Caseins composed of several similar proteins which form a multi-molecular, granular structure called a casein micelle. In addition to casein molecules, the casein micelle contains water and salts (mainly calcium and phosphorous). Some enzymes are associated with casein micelles, too. The micelle structure of casein in milk is an important part of the mode of digestion of milk in the stomach and intestine, the basis for many of the milk products industries (such as the cheese industry), and the basis for our ability to easily separate some proteins and other components from cow milk. Casein is one of the most abundant organic components of milk, in addition to the lactose and milk fat. Individual molecules of casein alone are not very soluble in the aqueous environment of milk. However, the casein micelle granules are maintained as a colloidal suspension in milk. If the micelle structure is disturbed, the micelles may come apart and the casein may come out of solution, forming the gelatinous material of the curd. This is part of the basis for formation of all non-fluid milk products like cheese.

      Caseins have an appropriate amino acid composition that is important for growth and development of the nursing young. This high quality protein in cow milk is one of the key reasons why milk is such an important human food. Caseins are highly digestible in the intestine and are a high quality source of amino acids. The casein proteins are found in the greatest amounts. In addition to being in your milk, these proteins are packaged and sold as protein powders. Understanding how your body uses casein proteins can help you understand if you should consume more of them.

2.1.2 Whey Protein

Centrifugation of the skim milk in an ultracentrifuge (usually about 50,000 x g or greater) results in pelleting of the casein and in a supernatant called whey (also sometimes called the serum phase of milk) which contains the water, lactose and soluble non-casein proteins. Once casein is removed, then by definition every other protein left in the milk preparation is a whey protein. There are many whey proteins in milk and the specific set of whey proteins found in mammary secretions varies with the species, the stage of lactation, the presence of an intramammary infection, and other factors. The major whey proteins in cow milk are ß-lactoglobulin and a-lactalbumin. a-Lactalbumin is an important protein in the synthesis of lactose and its presence is central to the process of milk synthesis. ß-Lactoglobulin's function is not known. Other whey proteins are the immunoglobulins (antibodies; especially high in colostrum) and serum albumin (a serum protein). Whey proteins also include a long list of enzymes, hormones, growth factors, nutrient transporters, disease resistance factors, and others.

The use of whey protein as a source of amino acids and its effect on reducing the risks of diseases such as heart disease, cancer and diabetes is the focus of ongoing research. Whey is an abundant source of branched-chain amino acids (BCAAs), which are used to fuel working muscles and stimulate protein synthesis. Most whey proteins are relatively less digestible in the intestine, although all of them are digested to some degree. When substantial whey protein is not digested fully in the intestine, some of the intact protein may stimulate a localized intestinal or a systemic immune response. This is sometimes referred to as milk protein allergy and is most often thought to be caused by ß-lactoglobulin.

2.2  Benefits of Protein in Cow’s Milk for The Human

          Milk protein serves many benefit within the human body, but we can divide into two groups, the primary benefit and general benefit.

2.2.1 The Primary Benefit

          The protein within cow’s milk has the primary benefit to provide and keep balance amino acids in the human body. When the proteins that we consume in our food are broken down through digestion into individual amino acids, these amino acids are then absorbed and reform in order to create new proteins that are then used by the body. The 20 types of amino acid are divided into two groups: essential and non-essential amino acids. There are 12 non-essential amino acids. They are termed non-essential as they can be manufactured by the body and do not have to be derived from food. Class of non-essential amino acids is tyrosine, cysteine​​, serine, proline, glycine, glutamic acid, aspartic acid, arginine, alanine, histidine, glutamine, asparagine.

The body, on the other hand, cannot produce the remaining 8 essential amino acids itself, and therefore they must be derived from the food that we eat. Class of essential amino acids is triptopan, threonine, methionine, lysine, leucine, isoleucine, phenylalanine, valine. Non-essential amino acids are just as important as essential amino acids, as without the other, new proteins that are needed by the body cannot be properly formed. It is therefore vital that a variety of foods are eaten in order to provide the body with all of the amino acids required.

Each amino acid has specific functions in the body. There are many functions and possible symptoms of deficiency of twenty amino acids and related compounds. Individual amino acids should not be taken for long periods of time. A good rule to follow is to alternate the individual amino acids that fit your needs and back them up with an amino acid complex, taking the supplements for two months and then discontinuing them for two months. Researchers warn against taking large doses of amino acids for extended periods of time. Moderation is the key. Some amino acids have potentially toxic effects when taken in high doses (over 6,000 milligrams per day) and may cause neurological damage. These include aspartic acid, glutamic acid, homocysteine, serine, and tryptophan. Cysteine can be toxic if taken in amounts over 1,000 milligrams per day.

2.2.2    The General Benefit

Generally, the benefits of protein which source from all of food are same. Proteins are very important molecules in our cells. They are involved in virtually all cell functions. Each protein within the body has a specific function. Some proteins are involved in structural support, while others are involved in bodily movement, or in defense against germs. Proteins vary in structure as well as function.

a.    Antibodies - are specialized proteins involved in defending the body from antigens (foreign invaders). They travel through the blood stream and are utilized by the immune system to identify and defend against bacteria, viruses, and other foreign intruders. One way antibodies destroy antigens is by immobilizing them so that they can be destroyed by white blood cells.

b.    Enzymes - are proteins that facilitate biochemical reactions. They are often referred to as catalysts because they speed up chemical reactions. Examples include the enzymes lactase and pepsin. Lactase breaks down the sugar lactose found in milk. Pepsin is a digestive enzyme that works in the stomach to break down proteins in food.

c.    Hormonal Proteins - are messenger proteins which help to coordinate certain bodily activities. Examples include insulin, oxytocin, and somatotropin. Insulin regulates glucose metabolism by controlling the blood-sugar concentration. Oxytocin stimulates contractions in females during childbirth. Somatotropin is a growth hormone that stimulates protein production in muscle cells.

d.   Structural Proteins - are fibrous and stringy and provide support. Examples include keratin, collagen, and elastin. Keratins strengthen protective coverings such as hair. Collagens and elastin provide support for connective tissues such as tendons and ligaments.

e.    Transport Proteins – are carrier proteins which move molecules from one place to another around the body. Examples include hemoglobin and cytochromes. Hemoglobin transports oxygen through the blood. Cytochromes operate in the electron transport chain as electron carrier proteins.

f.     Storage Proteins - store amino acids. Examples include ovalbumin and casein. Ovalbumin is found in egg whites and casein is a milk-based protein.

g.    Contractile Proteins - are responsible for movement. Examples include actin and myosin. These proteins are involved in muscle contraction and movement. The role played by the contractile proteins and by biochemical processes in the regulation of the mechanical function of the heart. The contractile proteins are but following the lead of the cellular elements concerned with the production of energy.

h.    Maintenance of proper fluid balance - proteins participate in the maintenance of osmotic pressure, which controls the amount of water that is found inside of cells.

i.      Maintenance of proper acid-base balance: Due to their ability to combine with both acidic and basic substances, proteins help to maintain the normal acid-base balance in the body.

CHAPTER III

CONCLUSION

3.1  Conclusion

So, it can be concluded that:

1.    The primary protein in cow’s milk are casein and protein whey. Caseins are highly digestible in the intestine and are a high quality source of amino acids. Most whey proteins are relatively less digestible in the intestine, although all of them are digested to some degree. When substantial whey protein is not digested fully in the intestine, some of the intact protein may stimulate a localized intestinal or a systemic immune response.

2.    The benefits of protein in cow’s milk can be divided into two groups, the primary benefit and general benefit. The primary benefits to provide and keep maintain the amino acid in the body. The general benefits such as antibodies, enzymes, hormonal, structural, transport of material, and so on.

REFERENCES

Booker, R. 2003. What is Milk Protein, (online), (www.wisegeek.com/what-is-milk-protein.htm, diakses 28 September 2012).

Cant, A., Marsden, R. A. & Kilshaw, P. J. 1985. Egg and Cows' Milk Hypersensitivity in Exclusively Breast Fed Infants with Eczema, and Detection of Egg Protein in Breast Milk. British Medical Journal 291(1):932-935.

Llyoid, E. 2011. The Role of Proteins in Humans: How Proteins Help Maintain Life, (online), (www.brigthhub.com/science/medical/articles/6050.aspx, diakses 28 September 2012).

Nall, R. 2011. The Primary Protein in Milk, (online), (www.livestrong.com/article/524631-the-primary-protein-in-milk/, diakses 28 September 2012).