脱酚及pH偏移处理对菜籽蛋白体外模拟消化的影响

研究了脱酚及pH偏移处理对菜籽蛋白(CPI)及乳液模拟体外消化的影响。采用蛋白凝胶电泳、显微镜观察、粒度分析等方法进行表征。结果表明,在体外消化的过程中,蛋白水解度(DH)整体呈上升趋势,经脱酚、pH偏移及二者协同处理后的DH分别增大了17.1%、2.6%和22.9%。仅脱酚处理使消化产物可溶性蛋白浓度提高了22.3%。SDS-PAGE的结果显示,cruciferin(12S)比napin(2S)更易于水解,并且脱酚导致蛋白在12 kDa以下的条带消失。pH偏移处理显著提高了CPI的自由基清除能力,并改善了由酚的脱除引起的自由基清除能力的降低。对于改性后的蛋白乳液,脱酚导致胃消化阶段更显著的乳液液滴聚集现象,同时降低了肠消化阶段的油滴大小。总的来说,脱酚处理提高了蛋白及乳液的消化率,pH偏移提高了蛋白的自由基清除能力。

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.