Abstract:To analyze changes in the quality of Cololabis saira during refrigerated storage and to establish a rapid method for assessing its freshness, the sensory scores, TVB-N values, TBARS values, total bacteria count, and electronic nose measurement signals of C. saira under storage at 4 ℃ were determined. The results showed that the sensory score declined during storage, mainly because of smell degradation during the initial period. Although changes in TVB-N values were relatively small in the first three days, they increased significantly (p<0.05) from the fifth day and reached 0.3 mg/g on day 11, along with the generation of volatile substances such as aldehydes, ketones, and acids. TBARS levels showed a rapid increase and caused a rapid decline in odor scores. The total bacteria count increased rapidly from the fifth day and reached 7.0 Log10 CFU/g on day 11, which was consistent with the TVB-N values. According to the sensory, physical, chemical, and microbiological indicators, C. saira had first-grade freshness in the first three days and second-grade freshness until day 7; the shelf life was estimated to be 9~11 d. The two-dimensional graphical result of the principal component analysis (PCA) revealed a clustered distribution with no overlaps in features. The electronic nose could fully characterize the changes in freshness of C. saira during refrigerated storage, and the freshness level estimated thus was consistent with that characterized by sensory evaluation, physicochemical indicators, and microbiological indicators. These results could serve as a technical reference for quick assessment of fish freshness.
