Physico-chemical properties, fatty acid composition and storage stability of Coula edulis Bail. seed oil from Côte d’Ivoire

Abstract

Hazelnut (Coula edulis B.) is generally used as food in the south of Côte d’Ivoire. Some physico-chemical properties and fatty acid composition of Coula edulis seed oil were investigated in this study. Seed oil was soxhlet-extracted with hexan to yield a golden-yellow oil. Coula edulis seed is rich in oil (34.85%) and this oil showed a refractive index 1.46, acid value 2.65 mg KOH/g, free fatty acids as oleic acid 1.31%, peroxide value 9.10 meq O2/kg, iodine value 91 g of I2/100 g, saponification value 191.00 mg KOH/g and unsaponifiable matter 0.98%. The fatty acid composition of Coula edulis seed oil gave total saturated fatty acids 5.23% and unsaturated fatty acids 94.76%, and revealed that oleic acid (93.66%) and palmitic acid (3.29%) are the most abundant unsaturated and saturated fatty acids respectively. The physico-chemical changes occurring in Coula edulis seed oil during 90 days of storage at room temperature (26.56±3.00°C, 82.00±5.00% RH) were also followed. Excepted refractive index and iodine value, some physico-chemical properties such as acid value, peroxide value and saponification value varied significantly (P0.05) during storage time and remains lower than the norm. These results suggest that Coula edulis seed oil seems to be interesting for food and industrial purposes since this oil of good quality is stable during the 90 days of storage.