A1 and A2 milk caseins-comparative FTIR and spectroflourimetry analysis

Around 35% of the total caseins are caseins, which are further classified as A(1) beta-caseins and A(2)-caseins, based on differences in the amino acid composition of both. A(2) is the wild type genetic variant of beta-casein while A(1) is the mutant. The present study aimed at the isolation of A(1) and A(2) casein from different cow milk sources and its characterization by using simple chemical techniques. viz. FTIR and spectrofluorimetry. The commercial milk sample from Bos indicus (Gir) (A(2)) was obtained from Bombay Panjrapole, Mumbai and two commercially available packaged cow milk samples (pasteurized, skimmed) namely from Gokul and Mother Dairy (A(1)) were also obtained for comparison analysis from the local market. The isolation of casein was performed by standard method and analyzed using SDS-PAGE, FTIR and spectrofluorimetry. There was evidence that the A(2) milk lacked histidine and rich in aromatic amino acids like tryptophan using FUR and speetrofluorimetry techniques.