Lipase-catalysed acidolysis for enrichment of medium-chain triacylglycerols in virgin coconut oil and its functional properties

Abstract

Lipase-catalysed acidolysis has emerged as a promising biocatalytic approach for producing structured lipids. In particular, the enrichment of medium-chain triacylglycerols (MCTs) in oils via lipase catalysis is attracting great attention due to their health benefits. In addition, MCTs are a known source of instant energy. In the current work, the immobilized lipase-catalysed enrichment of medium-chain triacylglycerols (MCTs) in a virgin coconut oil (VCO) matrix was achieved. Lipase -catalysed acidolysis of VCO with caprylic (C8:0) and capric acids (C10:0) was conducted to enhance the concentration of MCTs in a solvent-free system, employing two commercial lipases, Lipozyme RM IM from Rhizomucor miehei (1,3-specific) and Novozym 435 from Candida antarctica (non-specific). This study investigated various reaction parameters, including substrate molar ratio, reaction time, and temperature, using Lipozyme RM IM to optimize the catalytic conditions. A higher incorporation of capric acid was observed compared to caprylic acid when the reactions employed 10% lipase relative to the total mass of substrates at a molar ratio of oil to a mixture of caprylic and capric acids (50% each) of 1 : 4. The optimal conditions for achieving the highest MCT enrichment (∼42%) involved a reaction time of 8 h at 40 °C. The MCT enrichment in the VCO was evidenced by ¹³C NMR with inverse-gated ¹H-decoupling, GC, and HRMS. The structured VCO exhibited enhanced antimicrobial activity against selected foodborne pathogens while demonstrating no cytotoxic effects in in vitro cell viability assays, supporting its functional safety. These findings highlight the potential of enzymatically structured VCO as a value-added functional lipid for food and nutraceutical applications.