Influence of Gamma Irradiation on Microbiological, Biochemical, and Textural Properties of Bonito (Sarda sarda) During Chilled Storage
This study evaluates the influence of various doses of gamma irradiation on some quality aspects of iced bonito (Sarda sarda). Fresh bonito sections were aerobically packed and gamma irradiated with doses of 0, 1.5, 3, 4.5, 6, and 7.5 kGy, samples were then chilled during 21 days. Microbiological analyses showed the presence of mesophilic and psychrophilic germs just before irradiation treatment. These germs were eliminated at doses ≥1.5 kGy. The analyses of total volatile basic nitrogen (TVB-N), trimethylamine (TMA) as well as the texture analysis showed that irradiated samples preserved a good quality during 21 days of chilled storage, whereas the control showed putrefaction. Histamine content was reduced after irradiation treatment, such decrease strongly correlated with the applied dose level. Fatty acid composition survey demonstrated that gamma irradiation associated with aerobic packaging influenced significantly the lipid profile. Irradiation at doses of 6 and 7.5 kGy reduced significantly poly-unsaturated fatty acid fraction. Results demonstrated that irradiation amplified the rate of lipid oxidation as shown by an increased peroxide value especially at higher doses. Gamma irradiation at low doses was effective in extending the bonito's shelf-life through the improvement of its microbiological, biochemical and textural qualities up to 21 days of chilled storage.