Enzymatic hydrolysis of egg-white proteins in a membrane reactor

Abstract

The objective of this research was to improve antioxidative properties of egg-white proteins by means of enzymatic hydrolysis. For this purpose a continuous stirred tank reactor including polyethersulfone ultrafiltration module with a molecular weight cut-off of 10 kDa was employed. Several proteolytic enzymes have been tested in order to obtain best quality of peptide-based formulations intended for human consumption. Amongst proteases form Bacillus licheniformis (Alcalase), protease form Bacillus amyloliquefaciens (Neutrase) and protease from papaya latex (papain), the highest degree of hydrolysis (DH), as well as the best antioxidative properties of obtained hydrolysates, were achieved with Alcalase. Further optimization included finding of the optimal enzyme concentration and residence time. Results showed that the DH was directly dependent upon the enzyme concentration, while the permeate flow did not show any influence on the DH. The reactor was maintained in operation for 3 h at 50 °C and pH 8 with permeate flow of 2 cm3 min-1. Degree of hydrolysis reached steady value of 60 % after 75 min. Antioxidative properties were analyzed with DPPH method and confirmed with linear sweep voltammetry. Results undoubtedly show that the obtained products have improved antioxidative properties compared to untreated egg-white proteins.