Effects of Coupling of Polyphenol Removal and pH-shifting Processes on Digestibility of Canola Protein Isolate

The effect of phenol removal and pH-shifting treatment on in vitro digestion of canola protein isolate(CPI)and CPI stabilized emulsion was investigated. SDS-PAGE,microscopic observation,particle size analysis and other methods were used to characterize in vitro digestion. The results showed that in the process of simulated in vitro digestion,the degree of hydrolysis(DH)increased. DH of CPI treated with phenol removal,pH-shifting and synergistic treatment of the two increased by 17.1%,2.6% and 22.9%,respectively. Soluble protein concentration of digested products increased by 22.3% after dephenolization. SDS-PAGE showed that cruciferin was more susceptible to hydrolysis than napin,and the band below 12 kDa of dephenolized CPI was disappeared after trypsin digestion. pH-shifting treatment significantly increased radical scavenging ability of CPI,improved unsatisfactory effect caused by phenol removal process. As for emulsion digestion,dephenolization could promote emulsion droplets aggregation in gastric digestion stage,and reduced oil droplet size during small intestine digestion. In general,phenol removal process improved the digestibility of proteins and emulsions,and pH-shifting increased radical scavenging capacity of proteins.