【摘要】 为探索增稠剂对酸乳体系的影响作用机理,以在原料鲜牛乳中分别加入0·0%、0·1%、0·2%、0·3%的黄原胶制作的酸乳为材料,对其流变特性和微观结构进行了观测。结果表明:4种样品都是正触变性流体,其触变环面积之比为1∶1·08∶0·64∶0·77。在加入量为0·1%、0·2%和0·3%的三个样品中,随着黄原胶加入量的增加,酸乳样品的表观黏度和剪切应力逐渐降低。电镜观察显示,不加入黄原胶时酪蛋白相互凝集成立体网状结构,加入黄原胶后酪蛋白凝集胶束变成了散乱的片状结构。初步分析认为,黄原胶对酸乳发生作用的机理是通过其大分子的空间位垒效应干扰酪蛋白发生凝集的方式,导致酪蛋白胶束结构散乱,从而降低酸乳凝胶的表观黏度和剪切应力。更多还原

【Abstract】 In order to explore the effect mechanism of thicking agent to yogurt curds,the rheological and microstructure properties of the yogurt samples were observed,which were fermented by the fresh milk added with different amount of xanthan(0.0%,0.1%,0.2%,0.3%).The results showed that all of the four yogurt samples were positive thixotropic liquid and the area ratio of the four thixotropic rings were 1:1.08:0.64:0.77.The viscosity and shear stress decreased gradually with the increasing added amount of xanthan 0.1%,0.2% and 0.3%.The observation by electron microscope showed that the casein micelles aggregated and constructed cross-linked network structures when no xanthan added in the samples,while the casein curds became to the disheveled sheet structures in the samples added with xanthan.By primary analysis,the mechanism of these phenomena was considered that the extra added xanthan disturbed the aggregating styles between casein micelles with the space baffle effect of xanthan molecular and caused the dishevelment structure of casein micelles cluster and furthermore reduced the viscosity and shear stress of yoghurt curds.更多还原