0℃冷藏三文鱼片新鲜度综合评价

Comprehensive Evaluation on Freshness of Salmon Slices at 0 ℃ Storage

对0℃贮藏的三文鱼片的理化指标和微生物指标【包括挥发性盐基氮(TVB-N)值、2-硫代巴比妥酸(TBA)值、p H值、色差值、菌落总数】进行定期测定,用电子鼻分析其挥发性气味组分(包括主成分分析、负荷加载分析以及线性判别分析);结合感官评价,探究冷藏条件下三文鱼片新鲜度的变化规律。试验结果表明:0℃贮藏的三文鱼片的TVB-N值、TBA值、菌落总数都随贮藏时间的延长而增大;p H值先降低后增高;色差值L*值先增加后减小再增加,a*值与b*值与其相反;总色差值则先增加后减小;感官评定分数一直下降。采用电子鼻能很好地区分不同贮藏时间的三文鱼片,各理化指标间有很好的对应关系(P<0.01)。

Because of its high water and protein content, salmon is susceptible to microbial contamination during processing, storage and transportation. The physical and chemical indexes and microbial indexes of salmon slices stored at 0 ℃ were measured. Including the total number of colonies, volatile basic nitrogen（TVB-N） value, 2-Thiobarbituricacid（TBA） value, pH value, color difference value and sensory evaluation. The volatile odor that released in the process of cold storage was determined by electronic nose and analyzed using principal component analysis（PCA）, Loadings analysis（LA） and linear discriminant analysis（LDA）, aiming to reach the freshness change rule so that the quality of salmon slices stored under refrigeration temperature can be enhanced and the shelf life can be extended. The results showed the TVB-N value, TBA value and the total number of colonies value of salmon slices stored at 0 ℃ increase with the extension of storage time, pH value increased after cut first, color difference value L^＊value increase first and then increases again, a^＊values and b^＊values are in the opposite. The total color difference value first increase then decrease. Sensory evaluation score has been showed a trend of decrease and the physical and chemical indexes have very good corresponding relation with each other（P〈0.01）. Electronic noses can distinguish salmon slices under different time,and PCA analysis, LA analysia as well as LDA analysis can distinguish volatile odor changes of salmon slices during cold storage. There is a turning point in both LDA and PCA analysis diagram in 15 d consistenting with the conclusion of the detection of physical and chemical indicators. This study provides the reference for improving the quality and shelf life of salmon slices stored in cold temperatures.