Enrichment of Rice Bran Oil with α-Linolenic Acid by Enzymatic Acidolysis: Optimization of Parameters by Response Surface Methodology

Lipase-catalyzed enrichment of rice bran oil with n-3 fatty acid in order to obtain a structured lipid containing essential fatty acids has been optimized by response surface methodology. In this process, alpha-linolenic acid was used as an acyl donor using lipase-catalyzed acidolysis in hexane in presence of immobilized lipase from Rhizomucor miehei. The effect of incubation time and temperature, enzyme concentration and substrates mole ratio and their complex interaction on percentage incorporation of n-3 fatty acid, ratios of saturated fatty acid to polyunsaturated fatty acids, monounsaturated fatty acids to polyunsaturated fatty acids and n-6 to n-3 (18:2 to 18:3) fatty acids have been studied using a central composite rotatable design of experiments. The results showed that at the optimum conditions such as reaction time 4.5 h and reaction temperature 37. 5A degrees C, substrate ratio ranging from 1.0 to 1.9, enzyme concentration varying from 1.0% to 2.0% are needed to fulfill the conditions such as percentage incorporation of n-3 fatty acid a parts per thousand currency sign18%, ratio of saturated fatty acid to poly unsaturated fatty acid a parts per thousand yen0.42, ratio of mono unsaturated fatty acid to poly unsaturated fatty acid a parts per thousand yen0.8, and ratio of n-6 to n-3 a parts per thousand yen1.30.