Efficacy of Enriched Medium-chain Fatty Acids in Virgin Coconut Oil in Their Antibacterial Activity against Food Pathogens

Abstract

Free fatty acids (FFA) have been previously shown to be an effective bactericidal agent. In this study, the FFA mixture was attempted to isolate from virgin coconut oil (VCO) using lipases and was fractionated to obtain the enriched medium-chain fatty acids (MCFA) to compare its antibacterial efficacy against food pathogens. Three types of lipases – namely, lipozyme TL 100L, Candida rugosa lipase (CRL), and porcine pancreas lipase (PPL) – were used to compare their efficacy in VCO hydrolysis, in which CRL was found to be the most efficient lipase for the process of VCO hydrolysis at the water: buffer ratio of 1:5, lipase concentration of 5310 U/g, pH 7, and temperature of 40 °C. The vacuum-distillation process was successfully found to fractionate the initial FFA into three fractions: Fraction I containing MCFA (C8–C12) plus Fraction II (C12–C14) and Fraction III containing LCFA (C14–C20). Among these fractions, Fraction I was observed to be the most effective anti-agent against four out of five food pathogens (negative result against Salmonella typhimurium), followed by Fraction II and initial FFA. Antimicrobial activities of study fractions were found effective on both Gram-positive strains and Gram-negative strains.