草鱼冷藏过程中新鲜度的综合评价

Comprehensive Freshness Evaluation of Grass Carp(Ctenopharyngodon idellus) during Refrigerated Storage

为研究养殖草鱼冷藏过程中的鲜度变化,以菌落总数、挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量、pH值以及表征新鲜度的K、Ki、Fr、G、H、P值为指标,并结合电子鼻分析其新鲜度。结果表明,草鱼4℃冷藏过程中,随贮藏时间的延长,菌落总数和TVB-N含量呈增长趋势,与贮藏时间分别呈极显著相关(r=0.977)和显著相关(r=0.897);K、Ki、Fr、G值和P值均与贮藏时间呈极显著相关,相关系数r分别为0.955、0.953、-0.953、0.958和0.957;H值和pH值与其他实验指标相关性均不显著。菌落总数、TVB-N含量、K值及相关值(H值除外)和电子鼻结果能有效区分不同贮藏时间的草鱼。电子鼻检测结果和K值及相关值(H值除外)较菌落总数和TVB-N含量对新鲜度评价更为灵敏,pH值和H值不适宜作为冷藏草鱼的新鲜度评价指标。4℃冷藏条件下的草鱼,货架期为8 d,12 d后不可加工和食用。

In order to evaluate the freshness of farmed grass carp stored at 4 ℃, changes in total viable count(TVC), total volatile basic nitrogen(TVB-N), pH value, K value, and related values were investigated. Meanwhile, electronic nose was used to analyze the volatile components. The results showed that total viable count and TVB-N value increased gradually during storage and these changes were correlated with storage time. The values of K, Ki, Fr, G and P firstly increased and then stabilized. These changes were correlated significantly with storage time with correlation coefficients of 0.955, 0.953,-0.953, 0.958, and 0.957, respectively. Neither H value nor pH showed a significant correlation with each of the other parameters. The TVC, K value and the other related values except H value of grass carp could be distinguished effectively during different storage periods. Compared with TVC and TVB-N value, electronic nose as well as K value and the other related values except H value were more sensitive to freshness evaluation, while pH value and H value were not appropriate for the freshness evaluation. The shelf life of grass carp during 4 ℃ storage was 8 days, and fish samples stored for 12 days reached the upper limit of processing and edibility.