Chemical and biological evaluation of the African Walnut – Coula edulis (Baill). Bioavailability of Nutrient, using rat bioassay.

Abstract

The biological value of African Walnut (Coula edulis Baill) in the raw, boiled and oven dried forms were assessed. The average crude protein content varied bctwcon 8.96 and 21.80 percent which was highest for the oven dried and least for the boiled sample. A considerable amount of ether extract was recorded (41.00%) for the oven dried sample when compared to the other two samples. The observed concentration of energy and other extract content in Coula edulis appear to have a favourable effect on the nutritional value of the nut. Boiled sample contained relatively lower quantities of the nutrient determined. The drymatter digestibility of the raw, boiled and oven dried sample was 87.4, 75.8 and 89.0% respectively. Similarly, reduction occurred in the apparent digestibility of crude protein, crude fibre, ether extract and nitrogen tree extract. The study revealed increasing in weight gain for animals fed the boiled sample while lower weight gain were recorded for animals on raw and oven dried samples. The potential of consuming the boiled walnut as food by man and animals is evident by its nutrient concentration in term of carbohydrate, fat, crude protein and amino-acid profile.

Keywords. African Walnut, Wister rats, feed intake and digestibility.