壳聚糖-荔枝木质精油可食膜延长刀额新对虾的货架期

Shelf Life Extension of Metapenaeus ensis by Chitosan-litchi Wood Essential Oil Edible Films

为了解壳聚糖-荔枝木质精油可食膜对刀额新对虾的保鲜效果,以添加8%荔枝木质精油的壳聚糖复合膜(V/V,以壳聚糖溶液体积计)浸涂刀额新对虾,进行4℃保鲜试验;在6 d的贮藏期内,进行刀额新对虾的感官指标及品质指标(pH、挥发性盐基氮(total volatile base-nitrogen,TVB-N)、质构、色差及菌落总数)测定。研究发现:壳聚糖-荔枝木质精油可食膜浸涂使刀额新对虾的货架期有效延长,普通无菌保鲜膜保存货架期为3 d,浸涂复合膜保鲜可延长至6 d;感官及品质指标变化幅度均显著变缓,保鲜膜保存TVB-N含量在第4 d时为31.58 mg/100 g,已无食用价值;而复合膜保存在第6 d仍低于30 mg/100 g;保鲜膜保存pH在4 d时超过7.6,而复合膜保存在第6 d时丧失食用价值;从菌落总数角度看,保鲜膜保存第3 d达到腐败终点:6.89 lg(CFU/g);而复合膜保鲜的刀额新对虾菌落总数仍在一级鲜度。研究表明:壳聚糖-荔枝木质精油可食膜对刀额新对虾有较好的保鲜效果,可延长刀额新对虾的货架期3 d。本研究对精油壳聚糖复合膜的水产品使用方式提供参考。

To evaluate the preservation performance of chitosan-litchi wood essential-oil edible films for Metapenaeus ensis,shrimp were first subjected to dip coating to apply chitosan films with 8%litchi wood essential oil(V/V,based on the volume of chitosan solution)and then stored at 4℃for six days.Variations in the sensory and quality indices,including pH,total volatile base-nitrogen(TVB-N),texture,color difference,and the total number of bacterial colonies during storage,were determined.The results show that chitosan-litchi wood essential oil edible films can significantly prolong the shelf life of Metapenaeus ensis by doubling it from three days to six days.Meanwhile,the quality deterioration is slowed down considerably.The TVB-N content of shrimp in ordinary preservative films is 31.58 mg/100 g at day 4,indicating that the shrimp have no edible value.In contrast,the TVB-N content of shrimps in composite films is still lower than 30 mg/100 g at day 6.Furthermore,the pH of shrimps in ordinary preservative films exceeds 7.6 at day 4,while the shrimps in composite films have no edible value at day 6.The total number of bacterial colonies in shrimps in ordinary films equals 6.89 lg(CFU/g)at day 3,suggesting that decomposition reaches its end,while shrimps in composite films are still first-grade fresh in terms of the total bacterial colony number.In summary,chitosan-litchi wood essential oil edible films can preserve Metapenaeus ensis reasonably well and double its shelf life.This study provides a reference for the use of chitosan-essential oil composite films to preserve aquatic products.