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采用表面活性剂直接处理鲜胶乳离心浓缩法制备浓缩胶乳,先用尿素预处理新鲜胶乳后加入表面活性剂处理,再离心浓缩法制备浓缩胶乳。研究表面活性剂种类、尿素预处理时间和预处理温度及新鲜胶乳的pH值对处理所得浓缩胶乳蛋白质含量的影响。同时用傅立叶红外吸收光谱对2种处理方法制备的浓缩胶乳胶膜进行了表征。实验结果表明,鲜胶乳先经尿素预处理一定时间后加入阴离子表面活性剂处理,再离心浓缩制备浓缩胶乳,蛋白质含量显著降低。适宜条件下,浓缩胶乳的氮含量从质量分数0.430%下降至0.089%。红外光谱分析表明,先用尿素预处理新鲜胶乳,然后加入阴离子表面活性剂处理,再离心浓缩制备浓缩胶乳,胶膜在1 546 cm-1处蛋白质的酰胺II谱带几乎消失,在3 295 cm-1处N—H的伸缩振动峰明显减弱。
Concentrated latex was prepared by the direct treatment of fresh latex with surfactant and concentrated by centrifugation. The fresh latex was first pretreated with urea and then treated with surfactant, then the concentrated latex was prepared by centrifugal concentration. The effects of surfactant type, urea pretreatment time, pretreatment temperature and fresh latex pH on the protein content of the concentrated latex were investigated. At the same time, Fourier transform infrared spectroscopy was used to characterize the concentrated latex films prepared by the two methods. The experimental results showed that the fresh latex was pretreated with urea for a certain period of time and then treated with anionic surfactant. The concentrated latex was prepared by centrifugation to reduce the protein content significantly. Under suitable conditions, the nitrogen content of the concentrated latex decreased from 0.430% to 0.089%. Infrared spectrum analysis showed that the amide II band of the protein at 1 546 cm-1 almost vanished when the fresh latex was pretreated with urea, then treated with anionic surfactant and then concentrated by centrifugation. At 3 295 cm The stretching vibration peak of N-H at -1 significantly decreased.