Enzymatic catalyzed palm oil hydrolysis under ultrasound irradiation: Diacylglycerol synthesis

Diacylglycerol (DAG) rich oils have an organoleptic property like that of regular edible oils, but these oils do not tend to be accumulated as fat. Palm oil ranks first in the world in terms of edible oil production owing to its low cost. The aim of this study was to propose a new methodology to produce diacylglycerol by hydrolysis of palm oil using Lipozyme RM IM commercial lipase as a catalyst under ultrasound irradiation. The reactions were carried out at 55 °C with two different methods. First, the reaction system was exposed to ultrasonic waves for the whole reaction time, which led to enzymatic inactivation and water evaporation. Ultrasound was then used to promote emulsification of the water/oil system before the hydrolysis reaction, avoiding contact between the probe and the enzymes. An experimental design was used to optimize the ultrasound-related parameters and maximize the hydrolysis rate, and in these conditions, with a change in equilibrium, DAG production was evaluated.Better reaction conditions were achieved for the second method: 11.20 wt.% (water + oil mass) water content, 1.36 wt.% (water + oil mass) enzyme load, 12 h of reaction time, 1.2 min and 200 W of exposure to ultrasound. In these conditions diacylglycerol yield was 34.17 wt.%.

► Two methods for the use of ultrasound technology were proposed.
► Ultrasound is used to assist the whole reaction time leading to undesirable effects.
► Ultrasound is used before the reaction to improve the degree of hydrolysis.
► An experimental design was used to optimize ultrasound parameters.