不同涂液对豆腐的保鲜性研究

Application of different coatings in the preservation of tofu

通过共混法配制三种不同的保鲜液(壳聚糖,壳聚糖/Ca Cl2和壳聚糖/纳米Zn O溶液),利用扫描电子显微镜(SEM)对复合膜的表面进行观测,并采用这三种溶液涂膜处理豆腐,通过色度计和感官评价考察涂液对豆腐的保鲜效果。SEM照片显示,Ca Cl2和纳米Zn O在复合膜中均出现团聚现象,而后者在壳聚糖中的分散性略好。色度计对豆腐的明度L值和色度a、b值的测试发现,随着储藏时间的延长,豆腐的L值逐渐降低,这表明豆腐色泽逐渐暗沉,而a和b值无变化;同时豆腐的感官分值逐渐降低,豆腐逐渐腐败变质。结果与对照组相比,涂膜处理能够延缓豆腐色泽的变暗及变质,其中壳聚糖/Ca Cl2溶液的保鲜效果最好。

In order to find a proper fresh-keeping method for tofu, the solutions of chitosan, chitosan/CaCl2 and chi- tosan/nano-ZnO were prepared. The morphology of the chitosan/CaCl2 and chitosan/nano-ZnO composite films was characterized by SEM. In addition, the effect of the three coating solutions on tofu stored at 3 ℃ was observed by colorimeter and sensory evaluation experiment. SEM photos showed that the aggregation occurred probably resulted from the blending of inorganics with polyme. And the dispersion of nano-ZnO was better than CaCl2 in chitosan ma- trix. It was found that the lightness of L value and the sensory scores of tofu reduced with the increasing of the stor- age days. The former indicated that the lightness of tofu was decreased. Compared with the control, the decay of to- fu was delayed after treated by the coatings. And the preservative effect of chitosan/CaCl2 was the best for tofu.