Transesterification of phytosterol and edible oil by lipase powder at high temperature.

Phytosterol, which is hardly soluble in edible oil, was solubilized at a high concentration by converting it to FA esters by lipase-catalyzed transesterification at temperatures higher than 100°C using powdered Lipase QLM (Meito Sangyo Co., Ltd., Nagoya, Japan). Transesterification was conducted, in sunflower oil containing 10% phytosterol, without adding water or solvent, at 100°C. The conversion rate was 97.1% after 7 h of reaction. The effect of temperature on the conversion rate was also examined. Maximum enzyme activity occurred in the 100–120°C range, and 20% of the maximum activity was retained even at 130°C. When the lipase was recovered by filtration and recycled for repeated reactions at 90°C, the half-life of lipase activity was 260 h. Thus, edible oils with nutritional value could be produced by blending the phytosterol-containing sunflower oil into other edible oils. [ABSTRACT FROM AUTHOR]