不同方法制备的大豆分离蛋白功能性质的比较研究

摘要

采用普通的碱溶酸沉方法、Samoto法、钙离子沉淀法制备出几种大豆分离蛋白,并对其产率、总脂含量及溶解性、乳化性等物化性质和功能性质进行系统比较。结果表明：钙离子沉淀法制备的大豆分离蛋白（Less-LPSPI）的产率是碱溶酸沉大豆分离蛋白（APP）产率的65%,但高于由Samoto法提取的7S与11S两种大豆分离蛋白产率之和;Less-LP SPI的总脂含量比APP降低了45%,由Samoto法提取的亲脂性蛋白（LP）中总脂含量达到7.48%,而7S与11S蛋白中脂含量分别为1.45%、2.36%。在功能性质上,LP的溶解性、乳化活性均比较差,7S、11S质量比1：2混合蛋白的溶解性最好,而Less-LP SPI在pH≤10时溶解性低于APP;乳化性方面,Less-LP SPI的乳化活性稍低于7S、11S质量比1：2的混合蛋白及APP,但乳化稳定性远高于后者。总体上,Less-LP SPI脂含量少、乳化稳定性好,方法简单,且可提高其货架期。%Several soybean protein isolates(SPI) were prepared by acid precipitation,Samoto method and calcium-precipitation method,respectively.The characteristics including protein yield,total lipid content,solubility and emulsification of these SPIs were investigated.Our results showed that the yield of calcium-precipitation protein(Less-LP SPI) was lower than that of acid precipitation protein(APP),but higher than 7S,11S extracted by Samoto fractionation procedure.The lipid content of Less-LP SPI was decreased by 45% when compared with that of APP.The lipid content of lipophilic protein(LP) obtained from Samoto fractionation was 7.48%,but the lipid contents in 7S and 11S were 1.45% and 2.36%,respectively.The Samoto LP-rich fraction had inferior solubility and emulsifying properties.Less-LP SPI had lower solubility(pH ≤ 10) and emulsifying activity than APP,while Less-LP SPI had superior emulsion stability.In summary,Less-LP SPI has lower lipid and better emulsion stability and therefore can improve the shelf life of foods.