Enzymatic glycerolysis of palm oil fractions and a palm oil based model mixture; relationship between fatty acid composition and monoglyceride yield

Palm oil, palm stearin, palm olein and mixtures of palm stearin with rapeseed oil were reacted with glycerol at low moisture content using lipase from Pseudomonas fluorescens as catalyst. The content of monogiyceride (MG) in the reaction mixture at equilibrium was found to be higher at lower temperatures except for palm stearin where a higher diglyceride (DG) content was obtained. High temperature GC analysis revealed that at lower reaction temperatures the predominant reaction product was monopalmitin or, In the case of palm stearin, dipalmitin. Separation of the MG and DG fractions followed by determination of the fatty acid composition showed that at higher reaction temperatures the fatty acids were randomly distributed in these fractions but at 30–40 °C the saturated fatty acids were preferentially located in the MG fraction. A strong positive correlation was found between saturated fatty acid content and yield of MG at lower reaction temperatures.