湿热条件下低聚木糖-乳清分离蛋白的美拉德反应及产物乳化性与流变性研究

Maillard Reaction of Xylooligosaccharides with Whey Protein Isolate (WPI) under Wet Heating Conditions and Emulsification and Rheology of Maillard Reaction Products

本文研究了湿热条件下不同混合质量比(1:1、1:2、1:3、1:4,W/W)对低聚木糖与乳清分离蛋白(WPI)美拉德反应及其产物的乳化性与流变性的影响。UV-Vis吸光度值,p H和粒径大小显著变化表明,该条件下成功制备了WPI和低聚木糖的美拉德反应产物(MRPs)。数据显示,质量比为1:2的溶液体系美拉德反应程度最高;与未经过美拉德反应的体系相比,MRPs的平均粒径均减小而质量比为1:2的体系平均粒径最大;同时,美拉德反应提高了WPI的乳化活性和乳化稳定性,比例为1:2时MRPs具有最佳的乳化活性(38.63 m2/g)和乳化稳定性(65.23%);流变学测试表明糖基化修饰增强了WPI的凝胶性,比例为1:3时MRPs的储存模量提高最大,G’值高达约97,000 Pa(约WPI的7倍);在相同剪切速率下,MRPs溶液的表观粘度增加,而WPI的添加比例对体系粘度的影响占主导作用。上述研究表明,美拉德反应可改善WPI的乳化特性和凝胶特性。

In this work, the effect of mixing ratio(1:1, 1:2, 1:3, 1:4, W/W) on Maillard reaction between xylooligosaccharides and whey protein isolate(WPI) under wet heating conditions and emulsification and rheology of Maillard reaction products(MRPs) were investigated. Significant changes in browning intensity, pH and particle size showed that MRPs of WPI and xylooligosaccharides were successfully prepared. Results showed that the degree of Maillard reaction was the highest when the mixing ratio was 1:2. Compared to a system that has not undergone Maillard reaction, the average particle size of MRPs was reduced, and the largest value reached at the ratio of 1:2. The Maillard reaction improved the emulsification activity and emulsion stability of WPI, the MRPs showed the best emulsification activity(38.63 m2/g) and emulsion stability(65.23%) at a ratio of 1:2. Rheological tests showed that Maillard reaction modification enhanced the gelation of WPI, and the storage modulus of MRPs at a ratio of 1:3 had the biggest increase in which G’ reached a value of about 97,000 Pa, seven times the value obtained in the initial WPI gel. At the same shear rate, the apparent viscosity of MRPs solution increased compared to WPI, while the effect of WPI addition on the viscosity of the system predominates. The above results showed that the rheological properties and emulsifying properties of WPI could be modified after Maillard reaction.