Effects of high-intensity ultrasound treatment on functional properties of plum (Pruni domesticae semen) seed protein isolate

BACKGROUND In order to improve the functional properties of plum seed protein isolate (PSPI), the effects of high-intensity ultrasound (20 kHz) at different levels of power output (200, 400 and 600 W) on the water/oil holding, solubility, emulsifying, foaming, gel, film formation capacity and hydrolysis degrees of PSPI were investigated. RESULTS CONCLUSION Compared with untreated PSPI, ultrasound treatment improved water holding capacity, solubility, emulsifying properties, foaming capacity of PSPI. The gel prepared from ultrasound treated PSPI showed the higher gel strength compared with untreated protein. The film prepared from ultrasound treated PSPI showed higher tensile strength, lower elongation and permeability, denser and more compact microstructure compared with untreated protein. Ultrasonic treatment also improved the accessibility of PSPI to the protease (Alcalase, Trypsin, Neutrase, Protamex, Papain and Flavourzyme). Furthermore, the ultrasonic treatment could induce a decrease in particle size and relative fluorescence intensity, an increase in surface hydrophobicity, and changes in secondary structure and microstructure of PSPI. The changes in structure analysis of PSPI indicated that ultrasound treatment could induce molecular unfolding of protein, which might be helpful for improving the functional properties and efficiency of enzymatic hydrolysis. (c) 2018 Society of Chemical Industry