Enzymatic structural modification of monogalactosyldiacylglycerols for potential modulation of hydrophile-lipophile balance

This study aimed to enzymatically prepare structured monogalactosyldiacylglycerols (MGDGs) with different hydrophile-lipophile balance (HLB) values for use as emulsifiers. Acidolysis of Perilla frutescens-derived MGDGs with capric acid (10:0) was conducted to obtain structured MGDGs containing 10:0. Lewatit VP OC 1600-immobilized Rhizomucor miehei lipase was used as the biocatalyst. Structured MGDGs (HLB value = 2.95–7.17) containing 13.0–70.6 mol% 10:0 were obtained from P. frutescens MGDGs (HLB value = 1.93). A quadratic regression equation (R² = 0.920) to predict the 10:0 content of the structured MGDGs under the given conditions was established using response surface methodology. Using a linear regression equation (R² = 0.999) to predict the HLB value by 10:0 content, structured MGDGs containing 27.1–54.6 mol% 10:0 were predicted to have an HLB value of 4–6, indicating their potential applicability as hydrophobic emulsifiers. Structured MGDGs with a purity of ∼ 43% w/w were obtained from the reaction products using silica column chromatography.