Comparison of Casein Proteins in Cow, Goat, & Amul Milk: Study on Dry Weight %, Essays (university) of Biology

Download Comparison of Casein Proteins in Cow, Goat, & Amul Milk: Study on Dry Weight % and more Essays (university) Biology in PDF only on Docsity! Page 1 of 8 INTRODUCTION Milk as a biological fluid is well designed to the requirements of the specific offspring. Therefore, the composition of milk differs markedly among different species. Milk proteins as a major component of milk constituents play different important roles not only in nutrition and growth of the offspring but also in the different technological aspects as heat treatment, coagulation and rate of digestion. (Salem et al., 2009). Milk is the most nutritionally complete food found in nature. All kinds of milk, human or animal, contain vitamins (principally thiamine – VitB1, riboflavin – VitB2, pantothenic acid – VitB5, and vitamins A, B12, D), minerals (calcium, potassium, sodium, phosphorus, and trace metals), proteins(mostly casein), carbohydrates (principally lactose), and lipids (fats). Milk proteins from cow (Swaisgood, 1992), buffalo (Shamsia et al., 2008) sheep (Haenlein and Wendorff, 2006), camel (El- Agamy, 2006), goat (Park, 2006), human (El- Agamy et al., 1997), mares (El-Agamy et al., 1997) anddonkey (El-Agamy et al., 1997) were well studied. However, little is known about the composition and structural characterization of Egyptian goat milk. The present study was aimed to gain more information about casein milk proteins which prepared from milk of local breeds of cow, goat & Amul Milk. Global Milk Production Cattle are the most significant species in dairy production. At present, the number of animals bred for dairy purposes is numerous. Different regions around the world have adapted the particular species common to their area for the purpose of producing milk. In many regions of the world buffalo milk is often used. Camel milk is consumed in various countries that rear camel. Currently, global milk production is dominated by 5 animal species: dairy cattle, buffalo, goats, sheep, and camels. According to FAO Statistical Databases (2010) for the year 2009, the total world milk production accounted for 696.6 million kg3 of which 83.3% (580.5 million kg3) was cow milk, 13% (90.3 million kg3) buffalo milk, 2.2% (15.1 million kg3) goat milk, 1.3% (9 million kg3) sheep milk, and 0.2% (1.6 million kg3) camel milk. The major cow milk producers worldwide are The European Union (148.1million kg3), The United States of America (85.9million kg3), India (45.1million kg3), and Russia (32.3 million kg3).kg3). Nutritional Value The analysis allowed showing average values of basic milk components (protein, fat, and lactose) and to some extent minimize the impact of factors altering the milk composition, such as breed, feeding system, stage of lactation, or time of year. The energy value of milk from various animal species is closely related to the concentration of certain compounds in dry matter, especially the amount of fat. The highest energy value is characteristic of sheep milk— 5932 kJ/kg (Park and others 2007), lower than cow milk—3169 to 3730 kJ/kg (Barłowska 2007), buffalo milk—3450 kJ/kg (Kanwal and others 2004), camel milk—3283 kJ/kg (Shamsia 2009), and goat milk—3018 kJ/kg (Park and others 2007). The lowest energy value is specific Page 2 of 8 of donkey milk—1842 to 2051 kJ/kg (Guo and others 2007), horse milk—2080 to 2453 kJ/kg (Oftedal and others 1983), and human milk—2407 kJ/kg (Shamsia 2009). Milk lipids Fat is the major substance defining milk’s energetic value and makes a major contribution to the nutritional properties of milk, as well as to its technological suitability. Lipids form inclusions, which gradually increase in size, and finally migrate to the upper part of cell from which they are shed as globules into the collecting lumen. Milk fat globules have an average diameter of less than 0.1 μm to approximately 18 μm (El-Zeini 2006) Lipids form inclusions, which gradually increase in size, and finally migrate to the upper part of cell from which they are shed as globules into the collecting lumen. Milk fat globules have an average diameter of less than 0.1 μm to approximately 18 μm (El-Zeini 2006). The milk fat globules membrane (MFGM) contains the typical components of any biological membrane such as cholesterol, enzymes, glycoproteins, and glycolipids (Fauquant and others 2007). Milk mineral components Milk is an important source of mineral substances, especially calcium, phosphorus, sodium, potassium, chloride, iodine, magnesium, and small amounts of iron. The main mineral compounds of milk are calcium and phosphorus, which are substantial for bone growth and the proper development of newborns (Al-Wabel 2008). Milk proteins The main component of milk, which has a major impact on its nutritional value and technological suitability, is protein. Milk proteins are a heterogeneous group of compounds that differ in composition and properties. They are divided into casein complexes and whey protein fractions. Casein is the most important protein in milk, while the proportion of whey proteins is relatively low. Guo and others (2007) reported that the content of whey proteins in human milk is in the range of 0.68 to 0.83 g/100 g; in cow milk 0.55 to 0.70; 0.49 to 0.80 in donkey milk, and 0.74 to 0.91 g/100 g in horse milk. Sheep milk is the richest in whey proteins- 1.02 g/100 g (Dario and others 2008) and also contains the highest concentration of casein— 4.18 g/100 g (Dario and others 2008), similarly to buffalo milk, which contains 4.0 g of casein in 100 g of milk (Polidori and others 1997; Zicarelli 2004). Almost half less of casein is in cow milk, 2.46 to 2.80 g/100 g (Zicarelli 2004; Guo and others 2007); goat milk—2.81 g/100 g (Leitner and others 2004); and camel milk—2.21 g/100 g (Khaskheli and others 2005). Human milk also contains casein; however, in small amounts—0.32 to 0.42 g/100 g (Guo and others 2007); therefore, the ratio between whey proteins and casein is very high, 2.08, as mentioned by Shamsia (2009). Donkey and horse milk are also characterized by a low content of casein fraction, respectively, 0.64 to 1.03 g/100 g and 0.94 to 1.2 g/100 g (Guo and others 2007). There are three kinds of proteins in milk: casein, lactalbumins, and lactoglobulins. All three are globular proteins, which tend to fold back on themselves into compact, nearly spheroidal units and are more easily solubilizied in water as collodial suspensions than fibrous proteins are. They are “complete proteins”, so called because they contain all the amino acids essential for building blood and tissue, and they can sustain life and provide normal growth even if they are the only proteins, but they can contain greater amounts of amino acids than the proteins in egg and meat [1]. Page 5 of 8 MATERIALS AND METHODS REQUIREMENTS 1. Beakers (250 ml) 2. Filter-paper 3. Glass rod Weight box 4. Filtration flask 5. Buchner funnel 6. Test tubes 7. Porcelain dish 8. Different samples of milk 9. 1 % acetic acid solution 10. Ammonium sulphate solution PROCEDURE 1. A clean dry beaker has been taken, followed by putting 20 ml of cow’s milk into it and adding 20 ml of saturated ammonium sulphate solution slowly and with stirring. Fat along with Caesin was precipitate out. 2. The solution was filtered and transferred the precipitates in another beaker. Added about 30 ml of water to the precipitate. Only Caesin dissolves in water forming milky solution leaving fat undissolved. 3. The milky solution was heated to about 40oC and add 1% acetic acid solution drop-wise, when casein got precipitated. 4. filtered the precipitate, washed with water and the precipitate was allowed to dry. 5. Weighed the dry solid mass in a previously weighed watch glass. 6. The experiment was repeated with other samples of milk. Page 6 of 8 OBSERVATIONS Observation Data displayed in Table 1 present substantial variability in the basic chemical composition of milk from various animal species. A weight by volume analysis of literature data was applied for the 4 species of greatest importance in world milk production. This analysis allowed showing extracted dry weight by volume of casein protein from different animal species and to some extent minimize the impact of factors altering the milk composition, such as breed, feeding system, stage of lactation, or time of year (Table 1). Table- 1 Comparative Observation Table of Dry Weight of Extracted Casein Protein S.No. Name of Organisms species To calculated total Dry Weight of extracted casein protein with watch glass (w/v) w Weight of vacant watch glass g Dry Weight of extracted casein protein (w/v) W=w-g 1 Amul milk packet 38.23 35.33 38.73-35.33= 2.9 2 Cow 38.73 35.33 38.73-35.33= 3.4 3 Sanchi milk packet 38.33 35.33 38.73-35.33= 3.0 Page 7 of 8 RESULT Collected Amul Co. Milk, Cow milk & Sanchi Co. milk are used as casein protein sources to study the casein percentage in weight by volume (w/v) followed by the precipitation and pasteurization method and obtained result are 2.9% , 3.4 % & 3.0 % respectively. All these samples of milk contain different percentage of Casein Cow milk is the richest in casein proteins and Sanchi Co. Milk is lowest. CONCLUSION Different samples of milk contain different percentage of Casein. Cow milk is the richest in casein proteins and Sanchi Co. milk is lowest. The analysis allowed showing average values of basic milk components (protein- Casein, fat, and lactose) and to some extent minimize the impact of factors altering the milk composition, such as breed, feeding system, stage of lactation, or time of year.