Abstract: In this study, alcalase and flavourzyme were applied in combination at a ratio of 1:1 to hydrolyze defatted silkworm pupa protein and the hydrolysates collected at different hydrolysis times were assayed for total sugar, amino nitrogen, soluble nitrogen, peptide nitrogen and peptide and amino acid compositions. The results showed that the optimum concentration of substrate, temperature, enzyme dosage (relative to the mass of defatted silkworm pupa protein powder) and hydrolysis time were 8?g/100 mL, 50?℃, 1?g/100 g, and 9?h, respectively. The enzymatic process promoted the release of total sugar. Nitrogen was mainly existed in the form of peptide nitrogen, and the molecular masses of most peptides in the hydrolysates were lower than 1?kD. The main free amino acids in the hydrolysates were threonine, histidine, leucine, tyrosine, lysine and cysteine, accounting for about 60% of the total free amino acid content, and they contributed to the taste of the hydrolysates. Umami and sweet amino acids accounted for approximately 50% of the total amino acids in the hydrolysates with a ratio of hydrophilic to alkaline amino acid of about 1. The contents of peptide-derived amino acids were strongly linearly correlated with the umami of the hydrolsates..

Key words: reeling silkworm pupa, enzymatic hydrolysis, umami peptide, amino acids, taste characteristics