Effect of Milk Sources on Whey Protein and Fractions of Casein

Abstract

Aim: Milk from Cow, Buffalo and goat was used for the study of isolation and fractionation of casein and whey proteins. Buffalo and goat milk were subjected to physicochemical attribute studies and a detailed protein profile namely total protein, casein fractions α-, β- and κ casein and whey protein were separated by urea fractionation method. The aim of this study was to compare various casein fractions isolated from cows, Buffalo and Goat milk. The method of separating casein into its fractions is based on the solubility of the individual components in urea the solution. The separation of casein fractions was carried out in dissolving molar concentration of urea and the yield of fractions and total protein percentages were calculated. Buffalo and goat milk have comparatively higher total protein and whey protein content as compared to cow milk. Maximum whey proteins found in goat milk (20.58%) whereas cow milk had the lowest whey protein (19.29%). Among casein fractions, α fraction (16.64%) was found maximum in Buffalo milk followed by cow (14.92%) and goat milk (5.42%). The goat milk showed the highest level of β casein (17.81%) whereas, the lowest concentration of β casein was found in cow milk (9.38%). Study Design: A significant contribution to the total milk production of India comes from buffalo milk and goat milk. Despite that, Buffalo milk and goat milk are not being utilized for many products because of difference in composition of different species milk and their inherent problems associated in the production of products. Place and Duration of Study: Karnataka Veterinary Animal and Fisheries Sciences University (KVAFSU), Dairy Science College, Hebbal, Bangalore Karnataka, India Materials: The Goat milk samples were collected from Sinchana Goat and Sheep farm, Marenahalli village (Bengaluru Rural Dist) and Buffalo milk was obtained from Country Delight Pvt. Ltd., J. P. Nagar, Bengaluru, Karnataka. Cow milk used in this investigation was collected from SEDP, Dairy Science College, Hebbal, Bengalore.. All the glassware used was soaked in chromic acid solution, repeatedly washed with water, rinsed with distilled water and dried before use. For microbiological analysis dried test tubes, conical flasks, pipettes were cotton plugged and sterilized in a hot air oven. The chemicals and reagents used in this study were mainly of analytical grade procured from Prince Laboratory Company Pvt. Limited, Bangalore. The protein molecular weight markers used for the electrophoretic study were procured from Bangalore Genei Pvt. Ltd.  Methodology: Standard urea fractionation method adopted by Hipp et al was used for isolation and fractionation of caseins. Skim milk was prepared by subjecting whole milk for centrifugation, the skim milk obtained was acidified using 1 % hydrochloric acid at 200 C to obtain casein precipitate. Obtained whole casein was dissolved in 3.3 M urea at pH 7.5 and adjusted to pH 4.6 which precipitates the bulk of α casein and leaving k-caseins into soluble filtrates. Again the supernatant was adjusted to pH 4.9 diluted to 1.0 M urea and warmed to 300 C precipitating the β-caeisn. Further, addition of ammonium sulphate was used to isolate k-casein from the precipitate.    Results: The sources of protein had a significant influence on the total casein, casein fractions and whey protein content of different species. The highest quantity of total caseins (34.30g/l) and whey protein (8.87 g/l) were observed in buffalo milk followed by cow (28.52 g/l) and lowest was observed in goat milk (28.45 g/l). Total protein, casein and whey protein contents were greatly affected by the source of milk. Conclusion: The significant effect of source of milk on total protein, casein, its fractions and their yield was observed. highest yield of casein (54.31%) was observed in cow milk than buffalo milk (48.95 %) and lower yield was found in goat milk. Amongst the three species, highest per cent of β casein was noted in goat milk (54.05 %) followed by buffalo (36.03%) and cow milk (34.14%). Recommendation: Rasagulla will be consumed universally by all age groups globally. Thus, the consumption of Rasagulla helps in providing overall nutritional requirements. However, the study has been conducted on a pilot scale. Moreover, commercial production may necessitate huge cost on enzymatic modification of proteins and separation peptides for value addition.