Characterization of protein hydrolysate from silkworm pupae (Bombyx mori)

Silkworm pupae (Bombyx mori) were subjected to drying, defatting, and hydrolysis using two enzymes: Alcalase and Neutrase. The degree of hydrolysis by Alcalase (9.61%) was much higher than for Neutrase (2.91%). Enzymatic hydrolysis increased the amount of total amino acid from 9.4 (raw material) to 42.56-62.37 mg/100 mg with the highest productivity obtained using Alcalase hydrolysis. The molecular weight of the hydrolysate using the Alcalase treatment was less than that using the Neutrase treatment. The antioxidant activity of both protein hydrolysates was higher than for the raw material with the decrease in IC50 (the inhibitory concentration required to inhibit 50% of 1,1-diphenyl-2-picrylhydrazyl radical) and the improvement of ferric reducing antioxidant power. Both enzymatic treatments improved the water solubility of dried and defatted samples. The foaming capacity and stability was improved by Neutrase hydrolysis. In contrast, the emulsifying properties were not obviously improved by either Alcalase hydrolysis or Neutrase hydrolysis. Practical applications Enzymatic hydrolysis could improve the physicochemical and functional properties of dried silkworm pupae. Protein hydrolysate from Neutrase hydrolysis provided excellent antioxidant activity, water solubility, and foaming properties. Therefore, it could be used as an ingredient for the development of food with high antioxidant activity and foaming characteristics. Protein hydrolysate from Alcalase hydrolysis provided high protein content, total amino acid content, and water solubility index. Therefore, it could be used as the ingredient for protein enrichment in food product development.