Abstract:

To achieve an optimal degree of hydrolysis of soybean protein isolate (SPI) enzymatically hydrolyzed for the production of soybean bioactive peptides, single factor experiments were carried out to investigate 4 hydrolysis parameters (namely pH, hydrolysis temperature, enzyme dosage and substrate concentration) affecting Alcalase and Flavourzyme hydrolysis procedures of SPI and subsequently, according to experimental results, both enzymes were used for the combined hydrolysis of SPI and the optimal values of 4 hydrolysis parameters (namely pH, Alcalase dosage, Flavourzyme dosage and hydrolysis temperature) were investigated using a 4-variable, 3-level Box-Behnken design and response surface methodology. Results showed that a maximum degree of hydrolysis of SPI was achieved through the optimal double enzymatic hydrolysis for 7 h at 56 ℃ and pH 7.7 with Alcalase at a dosage of 110 mg/g substrate and Flavourzyme at a dosage of 90 mg/g substrate. Most of the soybean bioactive peptides obtained under such hydrolysis conditions exhibited a molecular weight below 1000 D.

Key words: soybean active protein, Alcalase, Flavourzyme, hydrolysis degree, production procedure