DEGRADATION OF THE LAURIC ACID OILS

The composition, properties, uses and degradation of the lauric acid oils have been discussed. Coconut and palm kernel oil contain approximately 40% medium chain fatty acids (C6:0-C12:0). The medium chain fatty acids in these oils are readily degraded by filamentous fungi belonging to the following genera, Penicillium, Aspergillus, Cladosporium, Fusarium, Trichderma and Monascus to give the methyl ketone one carbon atom less. This type of spoilage has been described as ketonic rancidity. Ketonic rancidity caused by Penicillium crustosum can be controlled by the total absence of fungal spores, a temperature less than 4 degrees C, water activity less than 0.91; the addition of sorbic acid at 1000 mg/kg or by the absence of oxygen. Coconut oil is a better substrate for ketonic rancidity than palm kernel oil due to the higher concentration of medium chain fatty acids in the former.