Co-oxidation of β-carotene in biphasic media

Co-oxidation of β-carotene is used to originate aroma compounds of the ionone family. This system involves xanthine oxidase-generated free radicals to cleave the carotenoid. However, free radicals also degrade the reaction products decreasing yields. In order to avoid this degradation, we investigated in this study the possibility of carrying out co-oxidation in biphasic media containing hexane, benzene or dichloromethane. Hexane and benzene enabled a good enzymatic activity, whereas, for dichloromethane, no co-oxidation occurred. β-Carotene’s bleaching was observed only when carotene was solubilized in the aqueous phase suggesting that free radicals did not enter the organic phase. With hexane and benzene, time courses of product accumulation were different from those obtained in aqueous media as degradation did not occur resulting in conversion yields about 11 times higher. These results show that it is possible to carry out β-carotene in biphasic systems, which enable to extract β-ionone and related molecules before further degradation by free radicals.