酶法修饰对乳蛋白功能性质的影响

The Effect of Enzymatic Modification on Functional Properties of Milk Proteins

该试验研究了酶法修饰对乳蛋白功能性质的影响。乳清蛋白的单酶和双酶修饰产物的乳化活性并没有显著的升高或降低,但乳化稳定性相比于原料乳清蛋白分别下降了18.1%和28.55%。脱脂乳粉的2种酶修饰产物的乳化活性及乳化稳定性都与原料脱脂乳粉基本保持同一水平,无明显差异。模拟体外消化过程检测结果显示,与原料乳清蛋白相比,经酶法修饰后的乳清蛋白产物一步消化和两步消化后释放的肽量均有所增加,并且单酶修饰乳清蛋白比双酶修饰乳清蛋白的消化性更好。疏水性检测结果显示,单酶体系和双酶体系修饰的乳清蛋白和脱脂乳粉的表面疏水性都明显高于相应的原料蛋白,其中,单酶体系修饰的乳清蛋白表面疏水性要比双酶修饰乳清蛋白略高,而双酶体系修饰脱脂乳粉高于单酶体系修饰脱脂乳粉,结果与固有荧光性分析的结果一致。该研究目的是确认单酶及双氧化酶体系修饰乳蛋白的可行性,阐明其对乳蛋白功能性质的影响,为乳蛋白功能性质的改善提供一种新途径,对拓宽乳蛋白在食品加工产业中的应用具有实际的理论指导意义和应用价值。

This experiment studied the effects on functional properties of milk proteins modified through enzymatic process.The emulsifying activity index(EAI)of single enzyme and binary oxidative system modified whey protein showed no significance,but the emulsion stability index(ESI)have reduced 18.1%and 28.55%respectively comparing to original WPI.EAI and ESI of two kinds modified SKMP kept the same with original skim milk powder.Result of in vitro digestion showed that the content of peptide released by modified WPI increased compared with origin WPI,and single enzyme modified WPI showed better digestibility than binary oxidative system modified WPI.The surface hydrophobicity of both single enzyme and binary oxidative system modified WPI together with SKMP increased significantly compared with original protein;the surface hydrophobicity of single enzyme modified WPI was higher than binary oxidative system modified WPI,while the binary oxidative system modified SKMP was higher than single enzyme modified SKMP.The conclusion was similar with the result of intrinsic fluorescence emission spectra.The purpose of this study was to confirm the feasibility of modifying the milk protein by single enzyme and binary oxidative system,and to elucidate its effect on the functional properties of milk protein.Therefore,this study provided a new way to improve the functional properties of the milk protein.The application in the industry had theoretical guiding significance and application value.