不同pH条件下乳清蛋白-桑椹多酚复合营养粉的制备及其理化性质

Preparation and Physicochemical Properties of Mulberry Polyphenol-whey Protein Complex Nutrition Powder under Different pH Conditions

近年来,蛋白质与多酚类物质的相互作用是食品领域的研究热点之一,两者的结合受到多种因素的影响,其中pH值是重要的影响因子。该文研究了不同pH值条件下桑椹多酚(Mulberry Polyphenols,MP)对乳清蛋白(Whey Protein,WP)理化性质和功能特性的影响。结果表明,桑椹多酚改变了复合蛋白粉的色泽、粒径大小和Zeta电位。同时,还提高了乳清蛋白的溶解性、乳化性能,在pH值3.0时乳清蛋白的乳化能力和乳化稳定性分别达到7.23 m2/g prot和89.56%,较对照组分别提高了2.66%和1.21%。通过高效液相色谱法对桑椹多酚-乳清蛋白粉中的单体酚类进行定量分析,在pH值5.0和7.0条件下结合的单体酚含量比pH值1.0和3.0高。此外,较空白对照组而言,添加桑椹多酚提高了乳清蛋白的DPPH自由基清除率、ABTS自由基清除能力和FRAP还原能力,最高分别达到89.28%、81.70%和530.95μmol/g prot。综上所述,利用动物蛋白结合植物多酚是创新功能食品组分的手段,反应体系的pH值对结合效率有重要影响,为今后食品蛋白质的理化稳定性和营养品在体内、体外生物利用度研究提供了新的思路。

In recent years,the interaction between protein and polyphenols has become one of the research hotspots in the field of food.The combination of protein and polyphenols is affected by many factors,among which the pH value is an important influencing factor.This article examines the influences of mulberry polyphenols(MP)on the physicochemical and functional properties of whey protein(WP)under different pH conditions.The results showed that MP changed the color,particle size and Zeta potential of complex protein powder.Meanwhile,the solubility and emulsifying properties of WP were also improved,and the emulsifying ability and emulsion stability of WP reached 7.23 m2/g prot and 89.56%at pH 3.0,which increased by 2.66%and 1.21%,respectively,compared with the control group.Quantitative analysis of monomeric phenolics in MP-WP powder was conducted by HPLC.The contents of bound monomeric phenolic compounds at pH 5.0 and 7.0 were higherthan those at pH 1.0 and 3.0.In addition,compared with the blank group,the addition of MP increased the DPPH free radical scavenging rate,ABTS free radical scavenging ability and FRAP reducing ability of WP,reaching the highest values,89.28%,81.70%and 530.95μmol/g prot,respectively.In summary,the use of animal protein to bind plant polyphenols is a means of innovating functional food components,and the pH value of the reaction system has an important impact on the binding efficiency,which provides a new idea for the study of the physicochemical stability of food protein and the in vivo and in vitro bioavailability of nutrients.