米糠多糖-乳清分离蛋白美拉德反应及其产物表征

Maillard Reaction between Rice Bran Polysaccharide and Whey Protein Isolate and Characterization of the Reaction Product

目的:通过米糠多糖(rice bran polysaccharide,RBP)与乳清分离蛋白(whey protein isolate,WPI)非酶褐变反应,探究反应时间对美拉德反应的影响,开发一种新型乳化剂制备纳米乳液包埋脂溶性物质。方法:RBP与WPI在干热条件下反应不同的时间,以A_(294 nm)、褐变程度、色泽变化、游离氨基含量等的变化监控美拉德反应进程,对美拉德反应产物的分子质量、粒径、乳化活性、乳化稳定性、微观结构进行表征,并用美拉德反应产物制备大豆油纳米乳液。结果:A_(294 nm)、褐变程度、色泽变化及游离氨基含量的变化,表明混合体系发生了美拉德反应,且随反应时间的延长产物颜色变暗;美拉德反应产物分子质量为17 kDa;反应12 h时的产物粒径分布较为均匀;RBP接枝到WPI分子上显著提高了WPI的乳化活性和乳化稳定性(P<0.05);WPI-RBP(12 h)@纳米乳液比WPI@纳米乳液更稳定、粒径均匀,能抵抗酸性条件下和盐离子存在条件下对乳液的不利影响。结论:WPI与RBP间的美拉德反应有效改善了WPI的特性,可作为一种新型乳化剂应用于食品领域。

Objective: The purpose of this study was to explore the impact of dry heating time on the Maillard reaction between rice bran polysaccharide(RBP) and whey protein isolate(WPI) in order to develop a new emulsifier for the preparation of nanoemulsions encapsulating lipid-soluble substances. Methods: The changes in absorbance at 294 nm(A_(294 nm)), browning degree, color and free amino acid content were monitored during the Maillard reaction under dry heating condition, and the molecular mass, particle size, emulsifying activity and emulsion stability, and microstructure of the reaction product were characterized. Meanwhile, the Maillard reaction product was used to prepare soybean oil nanoemulsion. Results: As indicated by the changes in A_(294 nm), browning degree, color difference and free amino acid content, the Maillard reaction took place, and the color of the product became darker with an increase in reaction time. The molecular mass of the reaction product was 17 kDa, and a uniform particle size distribution was observed at 12 h of reaction.The Maillard reaction significantly improved the emulsifying activity and emulsion stability of WPI(P < 0.05). Nanoemulsion containing WPI-RBP complex at 12 h of reaction was more stable than the one containing WPI and showed uniform particle size distribution, and it could resist the negative impact of acid and salt ions. Conclusion: The Maillard reaction between WPI and RBP effectively improve the emulsifying properties of WPI, and the reaction product can be used as a new emulsifier in the food field.