罗非鱼蛋白-大豆蛋白混合体系乳化性的研究

Study on Emulsifying Properties of Mixture System for Tilapia Protein and Soybean Protein

[目的]初步探讨动物蛋白和植物蛋白混合体系的乳化特性.[方法]分别以罗非鱼肉和低温脱脂豆粕为原料,采用碱溶-等电点沉淀法制备罗非鱼分离蛋白（FPI）和大豆分离蛋白（SPI）,固定蛋白浓度0.5％,试验pH值、NaCl浓度、多糖类型对不同比例混合蛋白体系乳化活性和乳化稳定性的影响.[结果]在试验范围内,FPI、FPI-SPI（2∶1）、FPI-SPI（1∶1）和SPI的乳化活性和乳化稳定性随pH值（3.0～10.0）的变化趋势基本一致,在pH4.0 ～5.0范围内最小,而在pH 3.0和pH 10.0条件下较大;在pH值3.0时,添加NaCl（0 ～0.4mol/L）会使体系乳化活性下降,而在pH值5.0和7.0时,试验蛋白体系的乳化活性均随NaCl的添加而增大;黄原胶、卡拉胶、瓜尔豆胶和壳聚糖的添加均可改善蛋白体系的乳化性,比较而言,瓜尔豆胶对混合蛋白体系乳化活性的改善最明显,黄原胶对混合蛋白乳化稳定性的改善最显著,壳聚糖效果最差.[结论]2种蛋白物理混合对体系乳化性的改善程度有限,而添加多糖能明显改善体系的乳化性.

[ Objective ] Emulsifying properties of mixture system for plant protein and animal protein were determined. [ Method ] Fish protein isolates （FPI） and soy protein isolates （SPI） were prepared by alkaline solution and isoelectic precipitation from Tilapia muslce and defatted soy flour produc. Effect of pH value, NaC1 concentration and polysaccharide on the emulsifying ability and emulsifying stability was studied for mixing system at O. 5% of protein concentration. [ Result] In the pH value range from 3.0 to 10.0, for FPI, FPI-SPI （2：1 ）, FPI-SPI （ 1 ： 1 ） and SPI system, the same trend was obtained for emulsifying properties with increased pH value. The minimum emulsifying activity and stabili-~ ty values were obtained at pH 4.0 - 5. O, while the larger values were observed at pH 3.0 and 10.0. At pH 3.0, emulsifying activity of mix- ing protein system decreased with addition of NaC1 （ range from 0 to 0.4 mol/L） , while emulsifying activity increased with NaC1 addition at pH 5.0 and 7.0. The addition of xanthan gum, carrageenan, guar gum and ehitosan could improve emulsifying properties of mixed protein sys- tem. In comparison, effect of guar gum on emulsifying activity of mixture system was most obvious, effect of xanthan gum on emulsifying ability was most remarkable, and no obvious improvement was observed for adding ehitosan. [ Conclusion ] Effect of physical mixing of two proteins on the emulsifying properties was limited, and the addition of polysaecharides can improve effectively the emulsifying properties.