茶多酚-壳聚糖复合液对虹鳟鱼肉贮藏品质和菌群结构的影响

针对虹鳟鱼在贮藏过程中易受到微生物的污染而发生腐败变质的问题,将3 g/L茶多酚和10 g/L壳聚糖混合制成复配保鲜剂,浸泡涂膜覆盖于虹鳟鱼表面。以感官评价、挥发性盐基氮含量、菌落总数及菌群结构等为指标,研究保鲜剂对4℃贮藏虹鳟鱼肉贮藏品质变化的影响。结果表明:茶多酚和壳聚糖单独使用或复合使用均能延缓腐败的发生;复配保鲜剂能将4℃贮藏虹鳟鱼的货架期从8 d延长至13 d,效果优于单独使用;未经处理的新鲜虹鳟鱼片菌群由16个菌属组成,腐败末期则以假单胞菌属为优势菌属,而复合保鲜剂涂膜会明显抑制假单胞菌属的生长,进而减缓鱼肉品质劣变。综上,茶多酚和壳聚糖的复配保鲜剂有助于通过抑制优势腐败菌的生长延缓4℃贮藏条件下虹鳟鱼的腐败变质。

Effects of Mixed Solution of Tea Polyphenols and Chitosan on Storage Quality and Microbial Community Structure of Rainbow Trout (Oncorhynchus mykiss) Fillets

To address the problem that rainbow trout are susceptible to microbial contamination and spoilage during storage, rainbow trout fillets were coated with a mixed preservative consisting of 3 g/L of tea polyphenols and 10 g/L of chitosan in aqueous solution at a volume ratio of 1:1 and then stored at 4 ℃. The effect of the preservative on the quality changes of rainbow trout flesh was evaluated in terms of sensory evaluation, total volatile basic nitrogen (TVB-N) content, total colony count and microbial community structure. The results showed that tea polyphenols and chitosan, whether used separately or in combination, could retard fish spoilage. The combination of preservatives extended the shelf life of rainbow trout from 6 to 13 days, which was better than the individual preservatives. The microflora of untreated fresh rainbow trout fillets consisted of 16 genera, with Pseudomonas being the dominant one at the end of spoilage. Coating with the combination of preservatives significantly inhibited the growth of Pseudomonas and thus slowed down the deterioration of fish quality. In conclusion, the combination of tea polyphenols and chitosan helped to slow down the spoilage of rainbow trout under storage conditions at 4 ℃ by inhibiting the growth of the dominant spoilage bacteria.