Document Type : Research Paper
Enzymatic acidolysis of canola oil through caprylic and capric acids was investigated for making structured lipids. Lipozyme TL IM, an sn-1,3 specific Thermomyce slanuginosa lipase, was utilized as the biocatalyst in the batch reactor. Reaction conditions were designed according to Taguchi’s method considering fatty acid to oil ratio, at three levels (1:1, 2:1, 3:1) , enzyme load (4, 8 and, 12%), temperature (45,55 and 65°C) and reaction time (15, 30 and 45 h). Fatty acid profiles of reaction products were analyzed through gas chromatography (GC) and iodine value (IV) variations determined from fatty acid composition. The reaction products, under optimum conditions, were compared in terms of the fatty acid distribution and molecular species of triacylglycerols. The results showed that fatty acid composition of canola oil was modified by the reaction. Acidolysis reaction in the presence of Lipozyme TL IM at 55°C, at the fatty acid to oil ratio of 3:1 and 12% enzyme level resulted in the highest molar percent of caprylic (37.2%) and capric (38.9%) acids in canola oil following 15 h of incubation. But, the difference between caprylic and capric acids in the acidolysis reaction for each enzyme was not significant. As a result of reaction with caprylic and capric acids, iodine value of canola oil revealed a significant decrease (from 118.5 to 78.8). Also, the results of the study indicated that by use of Lipozyme TL IM, 49.5 and 53.4 molar percents of caprylic and capric acids, respectively, were placed at sn-1,3 positions.