Multiple-stage silica-assisted liquid-liquid extraction: A promising extraction method for fractionation Mono-diacylglycerols(MDAGs) based Palm Stearin

Palm stearin-based mono-diacylglycerols (MDAGs) are food emulsifiers that have not yet been widely developed. Monoacylglycerol (MAG) and diacylglycerol (DAG) are the predominant components of MDAGs. Fractionation of MDAGs into MAG and DAG was currently performed by molecular distillation, chromatography, crystallisation or supercritical CO2. In order to reduce production costs and increase production efficiency, a simpler technique for MDAG fractionation is required. A ternary diagram was used to determine the optimum solvent composition for the extraction of MDAGs. Three different extraction methods, i.e. solid-liquid extraction, liquid-liquid extraction and multiple-stage silica-assisted liquid-liquid extraction, were used to fractionate MDAGs. The multiple-stage silica-assisted liquid-liquid extraction provides better separation performance than solid-liquid and liquid-liquid extraction. The extraction method with hexane solvent composition was able to produce DAG-rich fractions with a purity of 81.05% DAG and 16.47% MAG, while the binary solvent composition of hexane:ethanol (8:2) was able to produce MAG-rich fractions with a purity of 13.33% DAG and 83.45% MAG. This extraction method combines two separation mechanisms, i.e. adsorption on silica and solubility in the corresponding solvent. The latter method has the potential for production MAG-rich fraction and DAG-rich fraction. According to their respective functions, each of these fractions can be further developed.