Preparation of Diacylglycerol‐Enriched Oil from Free Fatty Acids Using Lecitase Ultra‐Catalyzed Esterification

Abstract

Production of diacylglycerol-enriched oil by esterification of free fatty acids (FFA) with glycerol (GLY) using phospholipase A1 (Lecitase Ultra) was investigated in this work. The variables including reaction time (2-10 h), water content (2-14 wt%, FFA and GLY mass), enzyme load (10-120 U/g, FFA and GLY mass), reaction temperature (30-70°C) and mole ratio of GLY to FFA (0.5-2.5) were studied. The optimum conditions obtained were as follows: reaction temperature 40°C, water content 8 wt%, reaction time 6 h, molar ratio of GLY to FFA 2.0, and an enzyme load of 80 U/g. Under these conditions, the esterification efficiency (EE) of free fatty acids was 74.8%. The compositions of the FFA and acylglycerols of the upper oil layer (crude diacylglycerol) of the reaction mixture were determined using a high temperature gas chromatograph (GC). The crude diacylglycerol from the selected conditions was molecularly distilled at 170°C evaporator temperatures to produce a diacylglycerol-enrich oil (DEO) with a purity of 83.1% and a yield of 42.7%.

Production of Diacylglycerol-enriched Oil by Glycerolysis of Soybean Oil using a Bubble Column Reactor in a Solvent-free System

“…It was also proved that MD was an effective approach to enrich DAG without thermal decomposition, which confirmed the results previously reported 22,27,28 . Figure 4 showed crystallization and melting curves of SO and DESO, and their onset/peak/offset temperatures and cooling/melting enthalpies were summarized in Table 2.…”

“…2.5 Analysis of acylglycerols and fatty acid composition by gas chromatography The acylglycerols composition of the final samples was analyzed by GC Agilent 7820A, Agilent Technologies Inc., Palo Alto, CA, USA equipped with a flame ionization detector FID according to the protocol by Wang et al 22 .…”

“…At a low enzyme load, lipase adsorbed to the oil/glycerol interface was below the saturation level, leading to low DAG yield. With increased enzyme load, the interface between SO and glycerol was gradually saturated with enzyme, which leaded to significant increase of the DAG produced 22 . However, there was no significant increase when the enzyme load was over 4 wt .…”

Fast Production of Diacylglycerol in a Solvent Free System via Lipase Catalyzed Esterification Using a Bubble Column Reactor

“…According to the protocol provided by Wang et al [33] and Zhang et al [34], A 30.0-mg sample of the crude product was dissolved in 2.0 mL hexane and filtrated through a 0.45-μm filter membrane. The analysis was performed using an Agilent 7820A (Agilent Technologies Inc., Santa Clara, CA, USA) gas chromatograph (GC) equipped with a split/splitless capillary injector and a flame ionization detector (FID).…”

“…However, excess water might cause acyl migration according to Soumanou et al [39]. Thus, it might need to add some water to activate the lipase in the initial stage, but to remove water generated to accelerate the reaction rate of the forward direction during esterification [25,33].…”