Effect of ultrasound-assisted alkaline treatment on functional property modifications of faba bean protein

Abstract

This study investigated alkaline shifting, ultrasonication, and their combination on functional modifications of faba bean protein isolate (FPI). The protein characterization revealed that the combined alkaline shifting/ultrasound treatment dissociated large aggregates of FPI into small ones, resulting in increased protein surface hydrophobicity and decreased free sulfhydryl groups. Such structural changes significantly increased FPI solubility from 12.2 to 40.4% to more than 95% at pH 3 and 7 and more than 80% at pH 6. Furthermore, the FPI modified by the combined alkaline shifting/ultrasound treatment produced emulsions with smaller particle size and superior stability at pH values 3 and 7. Likewise, a striking enhancement in foaming capacity (from 93% to 306-386%) and stability (from 10 s to 473-974 s) was achieved by the combined treatment. This study suggested that the ultrasound-assisted alkaline shifting treatment could be considered an effective method for improving FPI functional properties.

Keywords: Emulsifying and foaming properties; Faba bean protein; Protein aggregate; Ultrasound; pH shifting.