Physicochemical characterization, microbial decontamination and shelf life analysis of walnut (Juglans regia L) oil extracted from gamma radiation treated seeds

The physiochemical characterization and microbial decontamination of gamma irradiated (2–10 kGy) walnut seed oil were evaluated. The proximate composition, density and refractive index remained unaffected, whereas unsponifiable matter, iodine, sponification and free fatty acids values were almost unaffected up to an absorbed dose of 6 kGy and slightly changed at higher doses and similar trend was also observed for conjugated dienes, conjugated trienes, peroxide and para-anisidine values. The tocopherol contents and fatty acid also affected at higher absorbed doses. The microbial load was not detected in oil irradiated to an absorbed dose of 6 kGy. It was noted that variations in physiochemical characteristics were insignificant up to 6 kGy. The stored sample did not show significant changes in properties up to 3 months. From the results, it can be concluded that gamma irradiation may affect the physiochemical characteristics of walnut oil at higher doses. Therefore, an appropriate dose of gamma radiation is suggested to avoid any negative impact on nutritional value.