Quality Evaluation of Coconut (Cocos nucifera L) Oils Produced by Different Extraction Methods

Background: Despite the health benefits of coconut oil and its potential for economic development, the availability remain scarce and the cost very high. This is mainly due to poor extraction methods that in turn affect the yield and quality.

Aims: To produce coconut oil using different extraction protocols and to compare the quality of the different oil samples.

Study Design: The experimental set-up was of a completely randomized design.

Place and Duration of Study: Department of Food Science and Technology, Michael Okpara University of Agriculture, Umudike, Nigeria, between August and October 2018.

Methodology: Coconut oils produced by natural fermentation, centrifugation, freeze-thaw and solvent extraction protocols were analyzed for physical, chemical, sensory, microbial sensory properties.

Results: The solvent extracted oil had the highest oil yield (23.12%) whereas fermentation oil, the lowest (14.19%). The smoke and fire points had 173.75 -176.60°C and 262.45 - 266.65°C respectively. Solvent oil had the highest saponification (261.33 mgKOH/g) and acid values (0.77 mgKOH/g). The oils generally contained more lauric (46.22-48.16%) and myristic (18.03-19.83%) acids. They were also richer in vitamins A (6.22-18.65 ug/g) and E (2.92-4.28 mg/100 g) than D and K. Fermentation oil had the highest microbial count (12.93×02 cfu/ml) whereas solvent oil had the lowest (5.05×02 cfu/ml).

Conclusion: The methods used for the coconut oil extraction had significant impact on the quality of the oils. The highest oil yield was the centrifugation oil obtained from Centrifugation Method. The physico-chemical properties and fatty acid compositions of the coconut oils were comparable to international standards. Coconut oil extracted by freezing and thawing was the most preferred in sensory attributes.