14E-26 |
Lipase-catalyzed transesterification of fish oil and a fully hydrogenated soybean oil |
A. LOPEZ-HERNANDEZ1, C. F. Torres2, H. S. Garcia1, and C. G. Hill, Jr.2. (1) UNIDA, Instituto Tecnologico de Veracruz, M.A. de Quevedo # 2779, Col. Formando Hogar, Veracruz, Ver., 91897, Mexico, (2) Dept. of Chemical Engineering, Univ. of Wisconsin, Madison, 1415 Engineering Dr., Madison, WI 53706 Omega-3 polyunsaturated fatty acids (w-3 PUFA), especially long chain EPA and DHA, are widely recognized to have strong positive influence on human health. However, Intake of these fatty acids is usually low. A good way to raise the w-3 PUFA content in the diet is the enrichment of edible fats and oils. For this purpose, transesterification seems to have advantages over other lipase catalyzed reactions, since no further purification procedures are needed if hydrolysis is well controlled. In this work, our objective was to study the transesterification reaction between a docosahexaenoic acid rich fish oil and a fully hydrogenated soybean oil (FHSO). All reactions were performed at 70°C in batch reactors placed in an orbital shaker and agitated at 300 rpm. Lipases from Thermomyces lanuginosus (TL IM), Rhizomucor miehei (Chyrazyme L9) and Pseudomonas cepacia (Amano PS) were tested at two substrate weight ratios (70:30 and 80:20) for its ability to catalyze the transesterification reaction. Molecular sieves were added to the reaction mixture to prevent undesirable hydrolysis. The transesterification was monitored by following the changes in the triacylglycerol species present in the reaction mixture by RP-HPLC. Change in tristearin concentration was used as an indicative of reaction progress. Our results showed that, after 12 hours of reaction, the hydrolysis was always less than 10%. Consumption of tristearin ranged from 40%, for lipases L9 and PS, to 60% when using TL IM catalyst. The presence of newly formed triacylglycerols, formed mainly by stearic acid and DHA, in the reaction mixture is a clear indicative of the latter. The relatively low hydrolysis suggests that the use of molecular sieves was an effective way to control such undesirable process. This methodology has great potential for the development of w-3 PUFA enriched solid fats.
Session 14E, Nutraceuticals & Functional Foods: General I
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