Abstract: The food grade proteases such as Pepsin, Trypsin, ProtamexTM were twined to prepare high yield of Gln-bound peptides from wheat gluten. At first Trypsin, Pepsin and ProtamexTM were respectively determined their proper initial pH value, temperature, enzyme concentration and substrate concentration for wheat gluten hydrolysis. Then the wheat gluten was hydrolyzed with enzyme twined. The amino nitrogen content and the average amino acid numbers of peptides in hydrolysates were analysed, and the yield of Gln was determined by HPLC. The result showed that the combination of Trypsin and Pepsin performed a better hydrolytic effect on gluten. The optimum conditions are as follows: Trypsin at pH8.0, 50℃, S%=12.8% (W/V) and E%=9%(W/W) for 6 hours, then Pepsin at pH2.0, 40℃ and E%=5%(W/W) for 5 hours. The final average amino acid number of peptides in the hydrolysate is 2.20. The yield of Gln in peptides of Trypsin combined with Pepsin is 60.43%, the highest of all. It is the best combination for processing Gln-bound peptides from wheat gluten.

Key words:  , glutamine； glutamine-bound peptides； proteinase combination；