The effect of adding electrolyte solution to the cream demulsification technique on the purification of palm oil-based MDAG

Abstract

Glycerolysis is the simplest, least expensive, and most prevalent technique for producing mono-diacylglycerol (MDAG). MDAG, a product derived from palm oil, is crucial to the fat-based food sector. Chemical glycerolysis generally leaves crude MDAG with glycerol residues that exceed the European Union’s maximum (up to 7.5%); thus, it must be purified. Cream demulsification is one of the conventional ways of purification for separating glycerol residues from MDAG. This study investigates the impacts of adding electrolytes (calcium chloride, ammonium bicarbonate, magnesium sulfate, and sodium sulfite) and the effects of electrolyte concentration (2.5%, 5%, 7.5%, and 10% w/v) on the concentration of glycerol, monoglycerol, diglycerol, and triglyceride. Electrolytes have a role in transforming the MDAG emulsion system from a water-in-oil (w/o) system to an oil-in-water (o/w) system, causing the emulsion to break down and form cream. Glycerol and water create a polar phase (skim), whereas MDAG form a non-polar phase (cream). The analysis showed that the highest yield was obtained by adding 5% sodium sulfite (SS) electrolyte, which was 44.51±0.60%. Increasing the electrolyte concentration from 2.5% to 5% resulted in a larger yield, but a further increase of up to 10% did not improve the yield. The glycerol content also de creased from 13.36±0.82% to 1.8±0.32% with the addition of 5% SS electrolyte. This result is in line with the fact that the amount of MAG and DAG increased after the creaming demulsification with 5% SS electrolyte (41.68±1.23% and 25.75±0.26%, respectively).