Optimal Production and Structural Characterization of Erythorbyl Laurate Obtained through Lipase-catalyzed Esterification

• Published in: Food science and biotechnology Vol. 21; no. 4; pp. 1209 - 1215
• Main Authors: Lee, Da Eun, Park, Kyung Min, Choi, Seung Jun, Chang, Pahn-Shick
• Format: Journal Article
• Language: Korean
• Published: 2012
• Subjects: antioxidant; esterification; erythorbyl laurate; response surface methodology; immobilized lipase
• ISSN: 1226-7708; 2092-6456

Erythorbic acid, a stereoisomer of L-ascorbic acid, has been extensively used as an antioxidant but cannot be applied to lipid-based foods due to its poor lipophilicity. For this reason, synthesis of erythorbyl laurate (6-O-lauroyl-erythorbate) was achieved in acetonitrile using an immobilized lipase from Candida antarctica as a biocatalyst to increase its lipophilicity. Response surface methodology was used to optimize the erythorbyl laurate synthesis conditions in terms of enzyme content (1,000-5,000 propyl laurate unit, PLU), molar ratio of lauric acid to erythorbic acid (5-25), and reaction temperature ($25-65^{\circ}C$). The central composite experimental results showed the conditions for maximum molar conversion yield were as follows: enzyme content, 2,994 PLU; lauric acid to erythorbic acid molar ratio, 24.23; and reaction temperature, $53.03^{\circ}C$. The maximum molar conversion yield reached 77.81%, which was in agreement with the predicted value (76.92%). The erythorbyl laurate was purified and identified by Fourier transform-infrared spectroscopy (FT-IR). This research could help to develop an economical method of synthesizing erythorbyl laurate for use as a novel food-grade emulsifier with antioxidative activity.