超声预处理小麦蛋白与壳聚糖复合物胶体稳定性研究

Study on Colloidal Stability of Wheat Protein-Chitosan Complex Pretreated by Ultrasound

为研究超声预处理小麦蛋白与壳聚糖(UWP-CS)相互作用及其对复合物结构性质的影响,文章采用浊度法考察了超声和未超声条件下小麦蛋白-壳聚糖复合物(WP-CS)在不同复合比、pH、加热、盐离子等条件下的胶体稳定性。结果显示:超声和未超声的小麦蛋白-壳聚糖复合物形成稳定胶体的最佳条件均是WP∶CS为2∶1,pH为6,温度为20℃,无盐离子情况下,在低超声功率下,UWP-CS的稳定性强于WP-CS。紫外-可见吸收光谱、荧光光谱解析表明,经过超声预处理后复合物的荧光强度降低,紫外-可见吸收光谱的最大吸收峰逐渐升高且发生红移。这些现象说明超声处理改变了蛋白质的结构,增大了与壳聚糖链结合;另外,经过扫描电镜分析,超声预处理后的复合物与未超声的相比,颗粒分布更均匀且颗粒尺寸变小。

In order to study the interaction between wheat protein and chitosan(UWP-CS)pretreated by ultrasound and its effect on the structure and properties of the complex,the colloidal stability of wheat protein-chitosan complex(WP-CS)under ultrasonic and non-ultrasonic conditions is investigated by turbidimetric method under different combination ratios,pH values,heating and salt ions.The results show that the optimal conditions for the formation of stable colloids are WP∶CS of 2∶1,pH of 6,temperature of 20℃and salt-free ions,but the stability of UWP-CS is stronger than that of WP-CS under low ultrasound power.Ultraviolet-visible absorption spectrum and fluorescence spectrum analysis show that the fluorescence intensity of the composite decreases after ultrasonic pretreatment,and the maximum absorption peak of the ultraviolet-visible absorption spectrum gradually increases and occurs red shift.These phenomena indicate that ultrasound treatment changes the structure of protein and enlarges the binding with chitosan chains.In addition,by scanning electron microscopy analysis,the composite pretreated by ultrasound has more uniform particle distribution and smaller particle size than that without ultrasound treatment.