Process Biochemistry, Vol.49, No.10, 1682-1690, 2014
Preparation of active corn peptides from zein through double enzymes immobilized with calcium alginate-chitosan beads
Double enzymes (alcalase and trypsin) were effectively immobilized in a composite carrier (calcium alginate-chitosan) to produce immobilized enzyme beads referred to as ATCC. The immobilization conditions for ATCC were optimized, and the immobilized enzyme beads were characterized. The optimal immobilization conditions were 2.5% of sodium alginate, 10:4 sodium alginate to the double enzymes, 3:7 chitosan solution to CaCl2 and 2.5 h immobilization time. The ATCC beads had greatly enhanced stability and good usability compared with the free form. The ATCC residual activity was retained at 88.9% of DH (degree of hydrolysis) after 35 days of storage, and 36.0% of residual activity was retained after three cycles of use. The beads showed a higher zein DH (65.8%) compared with a single enzyme immobilized in the calcium alginate beads (45.5%) or free enzyme (49.3%). The ATCC kinetic parameters V-max and apparent K-m were 32.3 mL/min and 456.62 g(-1), respectively. Active corn peptides (CPs) with good antioxidant activity were obtained from zein in the ethanol phase. The ATCC might be valuable for preparing CPs and industrial applications. (C) 2014 Elsevier Ltd. All rights reserved.