ABSTRACT

The effects of different storage conditions on the oxidative stability of African pear (Dacryodes edulis) pulp oil was evaluated. African pear pulp oil (36.01%) was obtained through Soxhlet extraction method, divided into three (3) portions and stored under three different conditions: dark cupboard (20-25 C, acclimatized environment), a refrigerator (4- 8 °C), and at room temperature exposed to natural light (26-32 ·C), The oxidative stability of the oil samples was studied for eight (8) weeks and were assessed for their quality indices (free fatty acid, peroxide, iodine, viscosity, refractive index, tocopherol and thiobarbituric acid values). The results for dark cupboard condition at the beginning and end of storage ranged from 4.95 to 7.07% free fatty acid, 1.83 to 3.03 meq O3/kg peroxide value, 36.05 to 27.95 gl/100g iodine value, 19.87 to 27.97 Pa.s viscosity, 1.422 to 1.463 refractive index, 225.40 to 177.42 mg/I 00g tocopherol, and 0.94 to 2.07 mg/g thiobarbituric acid value. The results for oils stored under refrigerated condition (2-8 °C) at the beginning and end of storage ranged from 4.95 to 5.07% free fatty acid, 1.83 to 2.11 meq O/kg peroxide value, 36.05 to 34.05 g h/1 OOg iodine value, 19.87 to 23.45 Pa.s viscosity, 1.422 to 1.429 refractive index, 225.40 to 207.87 mg/100g tocopherol content and 0.94 to 1.08 mg/g thiobarbituric acid value. The results of oil samples stored at room temperature, exposed to natural light (26-32 ·C) ranged from 4.95 to 10.84% free fatty acid, 1.83 to 11.63 meq O/kg peroxide value, 21.35 to 36.05 g I/100g iodine value, 19.87 to 31.75 Pas viscosity, 1.422 to 1.493 refractive index, 225.40 to 161.56 mg/1 00g tocopherol, and 0.94 to 4.05 mg/g thiobarbituric acid value. Conclusively, African pear pulp oil samples stored under refrigerated storage condition had the best quality indices at the end of storage period (8 weeks), hence, better oxidative stability. However, samples stored inside a dark cupboard compared closely to samples stored under refrigerated condition.