Influence of hydrolysis temperature and pH on the selective hydrolysis of whey proteins by trypsin and potential recovery of native α-lactalbumin

Whey protein isolate (93.84 % protein) was hydrolysed using bovine trypsin (EC 3.4.21.4) at an enzymeto-substrate ratio of 1.0 % (w w1) over a range of temperatures and pH. Residual protein was quantified using reversed-phase high performance liquid chromatography. Genetic variants A and B of b-lactoglobulin (b-Lg) and a-lactalbumin (a-La) showed higher resistance to trypsin hydrolysis at 25 C than at 50 C with higher susceptibility of b-LgA than of b-LgB. Under the conditions trialled, the highest (67.87 %) residual pure a-La was at 25 C and pH 8.5 (2 h hydrolysis; degree of hydrolysis 7.11%), while the lowest (7.99 %) was at 50 C, pH 8.5 (5 min). Above pH 7.5 and 40 C, b-Lg dimeremonomer transition occurred resulting in improved trypsin hydrolysis. Trypsin hydrolysis outside the optimum pH and temperature offers potential for selective removal of b-LgAnd production of pure and native a-La.     «

Whey protein isolate (93.84 % protein) was hydrolysed using bovine trypsin (EC 3.4.21.4) at an enzymeto-substrate ratio of 1.0 % (w w1) over a range of temperatures and pH. Residual protein was quantified using reversed-phase high performance liquid chromatography. Genetic variants A and B of b-lactoglobulin (b-Lg) and a-lactalbumin (a-La) showed higher resistance to trypsin hydrolysis at 25 C than at 50 C with higher susceptibility of b-LgA than of b-LgB. Under the conditions trialled, the h...     »