Effect of different extraction methods on micro-component composition and oxidative stability of oil produced from African pear (Dacryodes edulis) mesocarp Oil

Abstract

Three different methods, including Soxhlet, traditional and screw press, were used to extract oil from African pear pulp. The oils were analysed for selected minerals and phytonutrients; stored for 4 weeks and analysed for oxidative changes. The micro-components results ranged from 0.00 to 41.50% for chlorophyll, 0.00 to 1.25 µg/100g for total carotenoids, 0.02 to 0.04 mg/100g for iron, 0.00 to 0.01 mg/100g for copper, and 18.25 to 208.50 mg/100g for vitamin E. The oxidative stability results showed that peroxide values ranged from 0.13 to 2.69 meq O2/kg in week 1 to 0.92 to 3.62 meq O2/kg in week 4; FFA ranged from 0.36 to 7.04% in week 1 to 0.39 to 11.47% in week 4; density ranged from 0.89 to 0.91 g/cm3 in week 1 to 0.91 to 0.98 g/cm3 in week 4; viscosity ranged from 17.17 to 51.57 RVU in week 1 to 20.31 to 55.05 RVU in week 4 and thiobarbituric acid level ranged from 0.02 to 1.11 mg/g in week 1 to 0.09 to 1.31 mg/g in week 4. Soxhlet extraction method produced oil of best quality with significantly (p < 0.05) higher mineral and phytonutrient contents, and of a longer storage stability.