Enzymatic Production of Diacylglycerols from High‐Acid Soybean Oil

Abstract In this study, high‐acid soybean oil, with acid values (Av) ranging from 10 to 50, was enzymatically deacidified for diacylglycerol (DAG) production. The effects of glycerol amounts were studied intensively. The glycerol amount could be calculated theoretically based on the Av of the raw oil (1 mol glycerol with 2 mol oleic acid to form 1 mol DAG, and 1 mol glycerol with 2 mol soybean oil to form 3 mol DAG). A total of 60–62% of DAG could be obtained and the free fatty acid (FFA) content was reduced to 0.36–0.66%. Increased glycerol did not lead to DAG content improvement. However, the glycerol amount based on just the deacidification theoretical calculation (1 mol glycerol with 2 mol oleic acid to form 1 mol DAG) was not feasible to reduce the FFA content. Moreover, Novozym 435 was rather stable in the present reaction procedure, no loss of activity was observed after 10 consecutive uses.