Evaluation of Mono-Diacyl Glycerol (MDAG) purification process to increase product yield

Abstract

Monodiacyl glycerol (MDAG) was successfully synthesized by esterification of palm fatty acid distillate (PFAD) and glycerol with acid catalyst. MDAG products with mono and diacyl glycerol content > 90% were obtained after purification through solvent extraction and crystallization at low temperature. However, the yield of purified MDAG products was only around 16.23% so it was not economically feasible. The aim of this study was to evaluate effect of the hydrolysis process before the esterification process and got the best conditions of solvent extraction in the MDAG purification, to improve yields of purified MDAG. The hydrolysis process was done on PFAD (or PFAD activation) to break down the remaining triglyceride and maximize the presence of free fatty acid that can react with glycerol. Evaluation of solvent extraction process included determination of crude MDAG and hexane ratio (1:10, 1:8, 1:4), determination of ethanol to water volume ratio (1:0, 1:0.5, 1:1, 0.5:1) with various immersion duration (24, 48, 72 h). The data analysis was done with a description method and completely randomized design method (CRD) with a significance level of 5% (P <0.05 %). The activation of PFAD was carried out by reacting PFAD with water at ratio of 1:6 (w/v). This process used para-toluene sulfonic acid (pTSA) as a catalyst, which added as much as 1.2% of the weight of PFAD. The hydrolysis process was done for one hour at 110 °C. From esterification using pre-treated PFAD obtained crude MDAG with FFA content of 4.69%, yield of purified MDAG of 24.7% with no FFA was detected. The best MDAG to hexane ratio was 1:10 which has a yield of purified MDAG of 19.30% and 0% FFA content. While the best ethanol to water volume ratio was 1:0.5 with immersion time for 24 h, where the yield of purified MDAG was 27.78%.