Carotenoid-5,6-epoxides reaction mechanism

It is well established that unsatnrated fatty acids undergo oxidation, via a radical reaction mechanism. Carotenoids undergo similar reactions and indeed do this so readily they can act as antioxidants in food materials. This antioxidant ability of carotenoids derives from their ability to form a resonance stabilised free radical. In certain controlled conditions chemical oxidation of carotenoids can give rise to epoxide formation and isomerisation of this to a furanoxide (Wong,... 

Fig. (16). Reaction mechanism for treatment of common carotenoid 5,6-epoxides (37 and 38) with acid [80].

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