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

Determination of the influence of the pH of hydrolysis on enzyme selectivity of Bacillus licheniformis protease towards whey protein isolate

“…The affinity of BLP towards b-lactoglobulin was 3 times higher at pH 9.0 than at pH 7.0. A similar effect was observed for the hydrolysis of WPI by trypsin, where the concentration of intact blactoglobulin was decreased faster at pH 8.5 than at pH 7.0 (150 mg min À1 at pH 8.5 and 50 mg min À1 at pH 7.0; Cheison, Leeb, Toro-Sierra, & Kulozik, 2011). This change in activity towards intact proteins may be related to the stability of the protein.…”

Pilot-scale purification of α-lactalbumin from enriched whey protein concentrate by anion-exchange chromatography and ultrafiltration

“…Schmidt and Poll (1991) reported that native α-La was highly resistant to trypsin while β-Lg was not. At lab scale, tryptic hydrolysis of β-Lg and discarding the fractions by membrane filtration seem suitable for achieving 100% purity of α-La (Lisak et al 2013;Cheison et al 2011); however, when upscaling, the purity drops to 90-95% and the recovery is quite low (Konrad and Kleinschmidt 2008). In order to achieve high purity, both at laboratory and pilot scale, chromatographic methods seem to be the best choice (Gurgel et al 2000;Ye et al 2000;Kristiansen et al 1998), and most often ion exchange chromatography is used.…”

Selective hydrolysis of α-lactalbumin by Acid Protease A offers potential for β-lactoglobulin purification in whey proteins

“…This MG attains an even more flexible conformational state during the early phases of the aggregation process at acidic pH, as deduced from the enhancement of its susceptibility to proteolysis by pepsin (Polverino de Laureto et al, 2005). It is resistant to trypsin hydrolysis under alkaline pH conditions, a property which was exploited for its selective purification (Cheison, Leeb, Toro-Sierra, & Kulozik, 2011;Konrad & Kleinschmidt, 2008). It is a source of important bioactive peptides, which are important for human health.…”

“…Besides, by converting one product to peptides in the process of purification, (bioactive) peptides may be produced which offers an additional health benefit. a-La is resistant to trypsin (Cheison et al, 2011;Konrad & Kleinschmidt, 2008) while b-Lg is resistant to pepsin (Schmidt & Poll, 1991). Since b-Lg is resistant to pepsin hydrolysis, it would be of both academic and industrial interest to investigate whether any other enzyme working optimally under acid pH could offer similar selectivity.…”

“…Already our group has demonstrated that under trypsin hydrolysis, whey proteins were selectively attacked by the enzyme in the order of depletion a-La < b-Lg B < b-Lg A (Cheison et al, 2011). The method offered potential for the purification of pure and less denatured a-La.…”