Effective lipophilic antioxidant enzymatically derived from Canadian crabapple

Phloridzyl octadecanoate was prepared by enzymatic reaction between the native phloridzin in Canadian crabapple (Malus baccata) extract and octadecanoic acid in the presence of Candida antarctica lipase. The antioxidant activity of the modified extract was assessed in rapeseed oil during accelerated storage at 65 degrees C and frying at 180 degrees C. Addition of 0.1% modified extract to refined, bleached, and deodorized rapeseed oil significantly improved storage stability with 40.7% decrease in the formation of lipid hydroperoxides at the end of the 7-day storage compared to rapeseed control sample without extract; however, no significant difference was observed in the potency of the modified extract and that of the native extract. On the contrary, the modified extract offered markedly better protection to the rapeseed substrate during frying, inhibiting polar component formation, and polymerization of triacylglycerol by up to 44%, compared to 26% by the native extract. At the end of the frying, French fries prepared in the presence of modified extract retained significantly more tocopherols than those prepared with the native extract indicating better protection of the oil's endogenous antioxidants by the modified phenolic extract. Practical applications: Poor lipophilicity is a major challenge to the application of natural polyphenolic compounds in edible oils. Equally challenging is the development of natural antioxidants that can maintain effectiveness under the stringent dynamic conditions of frying. Results from the current study demonstrated the possibility of overcoming these challenges, providing food processors with lipophilic natural antioxidants of practical importance in the frying process.