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, α-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. 5°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 ≤18%, ratio of saturated fatty acid to poly unsaturated
fatty acid ≥0.42, ratio of mono unsaturated fatty acid to
poly unsaturated fatty acid ≥0.8, and ratio of n-6 to n-3
≥1.30.