Partitioning of alpha-lactalbumin and beta-lactoglobulin in whey protein concentrate/ hydroxypropylmethylcellulose aqueous two-phase systems

FEDERICO JARA ANA; ANA M.R. PILOSOF

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Lugar: Ámsterdam; Año: 2011 vol. 25 p. 374 - 380

0268-005X

Whey protein concentrate (WPC) was fractionated by using hydroxypropylmethylcellulose (HPMC) at pH 6.5. Incompatible mixtures with different proportions of HPMC and WPC were prepared. After phase separation, the protein concentration in both phases was determined by the Kjeldahl method and the proportion of each protein by SDS-PAGE combined with image analysis. The results show that the low molecular weight proteins a-lactalbumin (a-lac) and b-lactoglobulin (b-lg) were retained in high proportion in the upper phase (about 90% compared to 64% of WPC). The most efficient condition to fractionate b-lg and a-lac was the phase separation of an incompatible mixed system with a high initial concentration of WPC and a low initial concentration of HPMC i.e., WPC 20%, wt/wt/HPMC 0.5%, w/w. It can be concluded that the thermodynamic incompatibility which arises from mixing WPC with HPMC could be used as a method for fractionation of whey proteins.