RANCIDITY OF TRADITIONAL COCONUT OIL: MICROBIAL CONTAMINANT AND FREE FATTY ACID CONTENTNur R. Adawiyah Mahmud*, Ernawati and Asmiati
One of the main factors that cause rancidity in oil is microbial activity. Microbes may produce enzyme which hydrolyze glycerides to become glycerol and free fatty acid (FFA). Volatile FFA may change the odor and flavor of oil. The aims of this research are to identify the microbial contaminant in seven samples of traditional coconut oils and two samples of factory coconut oil as a control; and to determine FFA content in these coconut oil samples. Microbial contaminant was detected by using pour plate method, while FFA content was determined by using acid-base titration. Results show that the common microbe contaminants in seven samples of traditional coconut oil are fungus: genus of Aspergillusand Rhizopus and the possibility of yeast and bacteria presence. Free fatty acid content in traditional coconut oil samples is between of 1 to 4,while FFA value in factory coconut oil is lower than 0.2. These results show that the higher of FFA value in traditional coconut oil than FFA value in factory coconut oil. The main factors that caused the difference ofFFA content is the presence of antioxidant. Factory coconut oils are using antioxidant to prevent hydrolysis and oxidation reaction occur in oil. Fungus contaminant in traditional coconut oil lead to the produce of enzyme that hydrolyze glyceride in oil to become FFA. Fungus contaminant in traditional coconut oil were possibly contaminated in packaging process. Generally, traders in traditional market use waste bottles (reuse of mineral water bottle) as a packaging bottle for coconut oil without any sterilized treatment.
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