Changes of Carotenoids in Atlantic Salmon by Heat Cooking and the Singlet Oxygen Quenching Activities of the Artificially Produced Carotenoids

Abstract

Carotenoids are widely distributed in food such as vegetables, fruits, fish and crustacean animals, and are thought to play an important role in human health. Although the above materials are often heated for cooking, few studies have reported the change of dietary carotenoids by these processes. In this study, we analyzed the carotenoids in heat cooked (steamed, grilled, fried, and microwaved) Atlantic salmon fed mixtures of astaxanthin, adnirubin, and canthaxanthin, (6 : 3 : 1, all trans) (salmons ingested feed containing 80 mg Panaferd AX/kg) for two years, using a silica gel HPLC column, and compared with carotenoids contained in raw salmon for the first time. As a result, the cis-carotenods (9-cis astaxanthin, 13-cis astaxanthin, 13-cis canthaxanthin, 13-cis adonirubin) derived from salmon fed carotenoids were clearly increased in heat cooked salmon. The rates of cis-isomers/total (trans + cis-isomers) were microwave heating (21-32%), steaming and grilling (17-24%), and frying (14-21%), respectively.We also examined the singlet oxygen quenching activities of the isolated natural and cis-isomer carotenoids (trans-or ciscanthaxanthin, adonirubin, astaxanthin and adonixanthin), and concluded that there were no significant differences between trans and cis-isomers (IC 50 2.4-7.4 µM).