预挂浆草鱼片冷藏过程中食用品质及菌群变化规律

Variation of Edible Quality and Microflora of Grass Carp Fillets with Sizing during Refrigerated Storage

为探究预挂浆草鱼片(grass carp fillets with sizing,GCFS)在冷藏条件下的品质变化规律及货架期,对4℃和10℃贮藏期间样品的菌落总数、菌相变化、持水力(water holding capacity,WHC)、挥发性盐基氮(total volatile basic nitrogen,TVB-N)、硫代巴比妥酸(thiobarbituric acid reactive substances,TBARS)、生物胺、ATP-关联化合物及K值等进行分析。结果表明,4℃和10℃贮藏样品的菌落总数分别于7 d和3 d接近或超过腐败阈值,说明低温会明显影响微生物生长和菌群组成,尤其是延缓不动杆菌属、希瓦氏菌属及气单胞菌属等生长。贮藏期内,样品间持水力变化差异不显著(P>0.05),pH在3 d时达到最低值,TBARS、TVB-N及特定生物胺(尸胺、腐胺、组胺、酪胺)含量逐渐升高。此外,核苷酸降解情况受贮藏温度的影响较大,4℃贮藏7 d和10℃贮藏3 d的样品K值超过推荐限值(60%),此时样品进入不新鲜状态。感官评价结果表明,鱼肉感官品质与贮藏时间呈负相关,且4℃贮藏5 d和10℃贮藏3 d的生/熟样品出现不同程度的质地软烂、红肉暗红及腥臭味加重等现象。综合各指标测定结果,为保证良好的食用品质,预挂浆草鱼片在4℃和10℃下的推荐货架期分别为3 d和1 d。

To determine the quality changes and shelf life of grass carp fillets with sizing(GCFS),the aerobic bacterial count,microbial succession,water holding capacity(WHC),total volatile basic nitrogen(TVB-N),thiobarbituric acid reactive substances(TBARS),biogenic amines,ATP-related compounds and K value of GCFS were analyzed during storage at 4℃and 10℃.Results showed that the aerobic bacterial count of GCFS stored at 4℃and 10℃approached or exceeded the limit on 7 d and 3 d,respectively,suggesting that low temperature significantly affects microbial amplification and microflora composition in GCFS,especially retarding the growth of Acinetobacter,Shewanella and Aeromonas.During storage,no significant difference(P>0.05)of WHC in samples was observed.The pH of GCFS reached the lowest level on 3 d,and the contents of TBARS,TVB-N and the specific biogenic amines(cadaverine,putrescine,histamine and tyramine)increased continuously.Furthermore,the changes in nucleotide degradation were greatly affected by storage temperature.The K value of GCFS exceeded the recommended limit value(60%)after 7 d of storage at 4℃or 3 d of storage at 10℃,meaning that the samples entered the stale state.The results of sensory evaluation showed a negative correlation between the quality and storage time,with the phenomena of textural softening,flesh discoloration and fishysmell aggravation in raw/cooked GCFS stored at 10℃for 3 d and 4℃for 5 d.Considering the results of various indicators and the pursuit of high edible quality,the suggested shelf life of GCFS at 4℃and 10℃was 3 d and 1 d,respectively.