Effect of enzymatic hydrolysis followed after extrusion pretreatment on the structure and emulsibility of soybean protein

Soybean protein has complex and compact natural structure resulted in unfavorable emulsifying property. Enzymatic hydrolysis followed after extrusion pretreatment has positive influence on the structure and emulsibility of soybean protein isolates. When the screw speed was 130 r/min, moisture content was 22%, and the extrusion temperature was 150 °C, the enzymatic hydrolyzed soybean protein had more flexible peptide with more surface hydrophobicity. From the FTIR analysis, the unordered structure transformed into the ordered structure. Meanwhile, proper extrusion conditions would increase emulsification of protein with smaller droplet and higher Zeta potential. These results suggested that soybean protein treated by enzymatic hydrolysis followed after extrusion pretreatment could be considered as an effective emulsifier in food applications.