Optimization of antioxidant peptide production in the hydrolysis of silkworm (Bombyx mori L.) pupa protein using response surface methodology.

摘要

Silkworm pupae may be treated as nutritional food due to their high protein content and functional properties. It has been reported that hydrolysis of silkworm pupal protein could convert high mol. wt. proteins into short chain peptides or even free amino acids which have physicochemical properties and antioxidative activity distinguishable from those of the original proteins, and which allow the silkworm pupae to be more easily be absorbed and digested by humans or animals. In this study, it was shown that silkworm pupal protein could be hydrolysed by several proteinases and, through optimization of hydrolysis technology, that the hydrolysates displayed a certain degree of antioxidative activity and could potentially be used to produce functional foods. Silkworm pupa hydrolysates were prepared from silkworm by-products using 6 commercial enzymes. Alcalase hydrolysates were found to have the highest degree of hydrolysis and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity. Degree of hydrolysis and DPPH radical-scavenging capacity showed similar trends, indicating that in order to obtain hydrolysates with high DPPH radical-scavenging capacity, a high degree of hydrolysis of the sample is needed. Response surface methodology was used to optimize hydrolysis conditions. Optimal enzyme-to-substrate ratio, pH and temp. were found to be 7.38 per mil, 7.97 and 60 degrees C, respectively. Under optimal conditions, max. DPPH radical-scavenging activity was 66.1%. It is suggested that silkworm pupa protein could be used as a natural functional food ingredient with antioxidative activity.