Physico-Chemical and Microbiological Parameters in the Deterioration of Virgin Coconut Oil
Ian Ken D. Dimzon, Melodina F. Valde, Jaclyn Elizabeth R. Santos,
Mark Joseph M. Garrovillas, Henson M. Dejarme, Jo Margarette W. Remollo,
and Fabian M. Dayrit
Department of Chemistry, School of Science and Engineering,
Ateneo de Manila University, Loyola Heights, Quezon City, Philippines 1108
The deterioration of virgin coconut oil (VCO) due to physico-chemical oxidation and hydrolysis and microbiological processes was studied. The physico-chemical oxidation of VCO in the air at room temperature was negligible. Oxidation of VCO was observed only in the presence of air, UV radiation, ferric ion (Fe3+), and high free fatty acid (FFA) content. Chemical hydrolysis was performed at varying moisture levels and temperatures. The rate of hydrolysis to produce FFAs was measured using 31P NMR under conditions of saturated water (0.22%) and 80°C was found to be 0.066 µmol/g-hr (expressed as lauric acid). At 0.084% moisture and 80°C, the rate of FFA formation was found to be 0.008 µmol/g-hr. The microbial decomposition of VCO was determined after four days of incubation at 37°C. At low moisture levels (<0.06%), VCO was stable to microbial decomposition. However, at higher moisture levels, there was an increase in the formation of organic acids, in particular, lactic acid, dodecanoic acid, succinic acid, acetic acid, and fumaric acid, indicating that microbial action had occurred. The most important conditions that influence the physico-chemical and microbial degradation of VCO are moisture, temperature, and the presence of microorganisms. These degradation processes can be minimized if the moisture level is maintained below 0.06%.
Virgin coconut oil (VCO) is defined as coconut oil that is extracted from fresh coconut meat and processed using only physical and other natural methods (PNS/BAFPS 2004; APCC 2006). These methods can include fermentation, centrifugation and use of an expeller. . . . . . . . . .
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