高酯果胶对酸化大豆蛋白凝胶流变及质构特性的影响

摘要

The effects of polysaccharides on the structure and functional properties of soybean protein can often be used as means of modification to soybean protein.In this experiment,soybean protein was used as raw material,0％,0.2％,0.4％,0.6％,0.8％ high-ester pectin was added to the soybean protein at pH 3.5,respectively.The effects of high-ester pectin on the rheology and texture characteristics of soybean protein gel were investigated.The results showed that high-ester pectin had great effects on soybean protein gel,and with the increase of the amount of high-ester pectin,the gel strength of soybean protein gel increased,and stability was also increased.When the addition amount of high-ester pectin was 0.4％,the gel strength was the biggest and the stability was the best.However,when the addition amount of high ester pectin was further increased,the gel strength of soybean protein began to decrease,the stability decreased and the structure deteriorated.The hardness,cohesion,adhesion,chewiness and recovery characteristics of soybean protein gel with the addition of high-ester pectin increased first and then decreased,and the water holding capacity of soybean protein increased with the increase of the amount of high-ester pectin as well.The best performance was at the amount of 0.4％ pectin.Microscopic electron microscopy showed that when the addition amount of high-ester pectin was 0.4％,the complex system showed uniform and dense network structure,and with the increase of high-ester pectin content,the complex system began to deteriorate gradually.Zeta potential measurements showed that little high-ester pectin can neutralize the positive charge of the soy protein surface which is beneficial to the formation of gel network structure.However,too much high-ester pectin could make the soy protein hydrophobic group roll,resulting in the aggregation of soy protein.%利用多糖对大豆蛋白的结构与功能性质进行修饰是大豆蛋白改性的研究热点.文中以大豆蛋白为原料,在pH值为3.5,质量浓度为50 g/L的大豆蛋白中分别添加0％、0.2％、0.4％、0.6％、0.8％的高酯果胶,考察高酯果胶对大豆蛋白凝胶流变及质构特性的影响.结果表明,高酯果胶对大豆蛋白凝胶的流变与质构特性有较大影响;随着高酯果胶添加量的增加,大豆蛋白凝胶的凝胶强度增强,并表现出良好的稳定性,果胶添加量为0.4％时,凝胶强度最大,稳定性最好,而当果胶添加量进一步增加时,大豆蛋白的凝胶强度开始减弱,稳定性降低,结构恶化;大豆蛋白凝胶的硬度、内聚性、黏着性、咀嚼性及回复性等特性随着果胶的添加先上升后下降,而大豆蛋白的持水性也随果胶的添加量的增加先上升后下降,在0.4％的添加量时,表现最佳.扫描电镜显示,当果胶添加量为0.4％时,复配体系呈现均匀致密的网状结构,而随着果胶含量再增加,复配体系结构开始逐渐恶化.Zeta电位测定表明,少量高酯果胶的加入能中和大豆蛋白表面正电荷,有利于凝胶网络结构的形成,但过多的高酯果胶会使得大豆蛋白疏水基团内卷,造成大豆蛋白聚集.