Abstract: The process parameters, temperature, enzyme dosage, hydrolysis time and pH, for enzymatic extraction of gluten from defatted wheat flour with α-amylase alone were optimized by one-factor-at-a-time method and response surface methodology. A mathematical predictive model was established for gluten purity as a function of the process parameters. The optimal process conditions were predicted using the model to be enzyme dosage 2.58%, temperature 58 ℃, pH 5.94, and hydrolysis time 4.0 h. Under these conditions, the predicted gluten purity was 80.28%. Further, in view of practical operating convenience and economic cost, the optimal process conditions were modified to be enzyme dosage 2.5%, temperature 55 ℃, pH 6.0, and hydrolysis time 4.0 h. The results from the validation experiments showed that the actual gluten purity was 77.57% under the modified conditions. Thus, the established model could provide accurate prediction.

Key words: response surface methodology, α-amylase, enzyme, wheat gluten