Abstract

Elaeis guineensis commonly known as the African palm oil, a monocotyledon widely used due to its nutritional and economic importance. The effect of deterioration of the harvested palm fruit on the physicochemical properties and fatty acid composition of palm oil was investigated. The palm fruit was processed after each period of deterioration (fresh, 7, 14 and 21 days after harvest) for oil production. AOAC Standard methods were used for the analysis. The result shows that the acid value (4.0±0.08, 4.94±0.33, 6.08±1.17 and 6.68±0.44) mg KOH/g, peroxide value (12.25±0.21, 14.53±0.78, 13.90±0.14, and 14.90±0.24) mg KOH/g, flash point (304.5±0.71, 300.5±2.12, 301.5±0.71 and 308.5±0.17°C) and boiling point (342±4.24, 339±1.41, 350±1.41 and 348±2.82°C) for fresh, 7, 14 and 21 days, respectively were above National Agency for Food and Drug Administration Control (NAFDAC) permissible limits. The free fatty acid value, saponification value, iodine value and melting point were below NAFDAC permissible limits. The fatty acid components showed that C₁₂ for day 7 was significantly high when compared with other groups. Also linolenic acid (18:3) composition was significantly different at day 21 when compared with the values for other days. The result reveals that some physiochemical properties of the oil (acid value, free fatty acid, refractive index, specific gravity, cloud point and boiling points) increased in days 14 and 21 oil. Thus, the quality of oil processed within seven days of harvest of the palm fruits was better.

Key words: Elaeis guineensis, physicochemical, fatty acid composition, deterioration.