Abstract:

Response surface methodology using Box-Behnken design was employed to optimize the preparation of Pi’xian
bean sauce koji. Based on single-factor experiments, inoculum amount, koji-making temperature and time were chosen as
independent variables, and the comprehensive evaluation score of koji quality indicators (protease activity and α-amylase
activity) was the response variable. As a result, a mathematical model was established by Box-Behnken design. The
optimal preparation conditions for Pi’xian bean sauce koji under actual operation circumstances were determined as 0.28%,
33.50 ℃ and 32.50 h for inoculum amount, koji-making temperature and time, respectively. The resulting product exhibited
a comprehensive quality score of 98.23.

Key words: Box-Behnken design, optimization, Pi’xian bean sauce, koji preparation