不同壳聚糖抗菌膜对草鱼保鲜效果的比较

本试验比较不同壳聚糖抗菌膜对草鱼鱼片的保鲜效果。试验以壳聚糖作为成膜材料，以葱、姜、蒜乙醇提取液作为抗菌剂，制备了4种涂膜液（壳聚糖、壳聚糖＋葱、壳聚糖＋姜、壳聚糖＋蒜），以蒸馏水作为对照，对草鱼鱼片浸渍涂膜后进行冷藏保存（8℃），分别在冷藏0、3、6天时取样，对鱼片进行感官分析，测定鱼片的细菌总数、挥发性盐基氮（TVB-N）和pH值。试验结果为4 种涂膜液组鱼片的感官评分均显著高于对照组，而细菌总数、TVB-N和pH显著低于对照组；壳聚糖＋葱、壳聚糖＋蒜组的感官评分显著高于壳聚糖组，而细菌总数、TVB-N和pH之显著低于壳聚糖组。试验结果表明，壳聚糖涂膜利于草鱼鱼片的贮藏，添加葱、蒜提取液可提高壳聚糖涂膜的保鲜效果。

Comparison on preservation of grass carp with different chitosan coatings

The effects of chitosan coatings on preservation of grass carp （Ctenopharyngodon idellus） fillets were studied in this experiment. Four chitosan based films were designed, treatment 1 （1.5% chitosan）, treatment 2 （1.5% chitosan ＋ onion ethanol extract）, treatment 3 （1.5% chitosan ＋ ginger ethanol extract）, and treatment 4 （1.5% chitosan ＋ garlic ethanol extract）, taking distilled water as the control group. Fish fillets were dipped into the solution described above for 5 minute, and then stored in a refrigerator maintained at 8~C . Sensory evaluation, total bacterial counts, total volatile basic nitrogen （TVB-N） and pH of the fillet were determined at 0, 3, 6 day of the experiment. Sensory evaluation of all treatment groups were higher than that of the control group, but their bacterial counts, TVB-N and pH were all lower than those of the control group. Sensory evaluations of treatment 2 and 4 were higher than that of treatment 1, and their bacterial counts, TVB-N and pH were all lower than those of the treatment 1. Those results indicate that chitosan coating can inhabit the microbical growth and protein decomposition, and has a good ability to maintain the quality of fish fillet during storage; the extractions of onion and garlic have the antimicrobial ability and can increase the effectiveness of chitosan film in fresh-keeping.