A comparison of native state of casein micelles of buffalo and cow milk and its molecular changes under different physico-chemical conditions

Buffalo milk is the second most produced milk in the world after cow milk with about 13% (89.3out of 693.7 billion litres) contribution in the world’s milk production. Buffalo milk increased ata double rate as compared to cow’s during last decade at global level. 92% of this milk isproduced in India and Pakistan. This milk is majorly handled by “informal sector” in all itsproducing countries except Italy.Quantitatively, buffalo milk is richer in all major constituents like fat, lactose, minerals andproteins particularly in casein contents than that of cow milk (casein concentration of buffalomilk is equivalent to total protein concentration of cow milk). Caseins are present in the form ofsupramolecular spherical colloidal structures named casein micelles like other milks. Caseinmicelles play a key role in milk for its biological and technological functionalities. Despite of lotof literature on casein micelles of cow milk, its micellar organization and dynamics are not wellknown whereas the knowledge on casein micelles of buffalo milk is even far less especially in itsnative state and under different physico-chemical conditions.The objective of this study was to gain knowledge on casein micelles of buffalo milk in its nativestate and its molecular changes as a function of different physico-chemical conditions (ionicstrength, acidification, alkalinisation, microfiltration/diafiltration and heat-treatments). Thecomparison with casein micelles of cow milk was used as a reference throughout the study.Biochemical, physic-chemical, molecular, microscopic, macroscopic, physical and organolepticapproaches were used to compare casein micelles of both milks. The proportion of casein/solubleproteins was 80/20 in both milks. In native state, casein micelles of buffalo milk were higher inconcentration, bigger in size, less hydrated, more mineralized as compared to casein micelles ofcow milk with similar charge and casein classes. The comparison of amino acids sequences ofcasein micelles showed a homology of 95% in both milks which globally depicts the similarmolecular organization of caseins. Casein micelles showed similar behavior against differentphysic-chemical conditions like cow milk qualitatively but due to quantitative differences, therefound some delays in molecular changes in the buffalo’s casein micelles.It showed that buffalo milk can be employed for the production of products which are alreadybeing produced by cow milk like different types of cheeses and to prepare casein constituents.