Production of Eicosapentaenoic Acid Concentrate and Phytosteryl Ester From Anchovy Oil by Combined Low‐Temperature Crystallization and Enzymatic Esterification

Eicosapentaenoic acid (EPA) concentrate was prepared from free fatty acid from anchovy oil via a combination of low‐temperature crystallization and Candida rugosa lipase‐catalyzed esterification. Two solvents, acetonitrile and acetone, were employed to enrich EPA by low‐temperature crystallization, and EPA was enriched in the liquid fraction obtained with both solvents. The EPA content increased from 17.2% in the original anchovy fatty acids to 52.0% and 42.3% when crystallization was performed with acetonitrile at −40°C and acetone at −80°C, respectively. As a second step, lipase‐catalyzed esterification of phytosterol with the EPA concentrates obtained from crystallization was conducted. After esterification, the EPA content in the unesterified fatty acid fraction increased markedly, whereas the palmitoleic acid (a Δ‐9 fatty acid) content decreased significantly due to the strong selectivity of C. rugosa lipase toward palmitoleic acid. EPA enrichment was more efficient when the EPA concentrate obtained using acetone, rather than acetonitrile, was used as the substrate for esterification.