Shelf life and biochemical changes of chilled Atlantic chub mackerel, Scomber colias, treated with extremophilic microbial films' extracts

Abstract

To get rid of harmful effects of synthetic preservatives and develop new ones from natural sources, extracts of microbial films from extreme habitats of geothermal spring and hypersaline lake in Western Desert, Egypt, were used for chilled Atlantic chub mackerel, Scomber colias, preservations. The aqueous extracts of extremophilic microbial films showed considerable contents of total phenolic and flavonoid contents and good antioxidant activity. The cytotoxicity test of 2% w/v concentrations on normal cells of liver and colon showed very weak effects and the cell viabilities ranged between 95.09 and 98.14%, while the cell viability of carcinoma cells was in the range of 88.74–98.9%. We tested the effect of aqueous extracts of these films on microbial and biochemical characteristics changes of chilled Atlantic chub mackerel. Concentrations of 0.5, 1.0, 1.5 and 2.0% w/v were applied. Total plate count (TPC), pH, value and acid value (AV), total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N) content, thiobarbituric acid value (TBA) and free fatty acids (FFA) were investigated for 8 days of storage at 5°C. Principal component analysis (PCA) showed good understanding of the effect of extremophilic microbial films on biochemical features of chilled Atlantic chub mackerel and revealed that the best evaluated TPC and other biochemical characteristics were found at extremophilic microbial levels of 1.0 and 1.5% w/v till the 8th day.