Enzymatic synthesis of lipophilic lutein–PUFA esters and assessment of their stabilization potential in EPA–DHA rich fish oil matrix

Abstract

The objective of the present study was to synthesize ω-3 polyunsaturated fatty acid esters of lutein and to evaluate if esterification can stabilize the both bioactive molecules. Both ω-3 polyunsaturated fatty acid and lutein are prone towards auto-oxidation in their free form. Free lutein extracted from the marigold petals was enzymatically esterified using Candida antarctica NS435 Lipase B, with the ω-3 long-chain polyunsaturated fatty acids. The lutein esters were purified, characterized and finally assessed for their protective role against oxidative degradation in bulk fish oil matrix. The antioxidative effect of these esters was compared with commercial antioxidants of natural origin, i.e., α-tocopherol and a synthetic antioxidant, i.e., tert-butylhydroquinone, at a dosage of 200 mg/L. Both free lutein and lutein–polyunsaturated fatty acid ester had significantly promoted the oxidative stability of bulk fish oil. But based on dose–response relationship, lutein–polyunsaturated fatty acid ester was found to be more efficient than free lutein, in protecting fish oil from secondary oxidation, thereby augmenting their shelf life. Given the high nutraceutical value, potent antioxidative potential and organic origin, it is only relevant to incorporate lutein esters as natural preservative and stabilizers in edible oils.