Effect of weevil infestation on the caffeine content of stored kolanuts (Cola nitida Schott Vent. et Endl.) in Maiduguri, Nigeria

An assessment uf the effect of weevil infestation on the caffeine content of red and white cultivars of kolanut. Cola nitida (Vent). Schott et Endl., was carried our in Maiduguri, northeastern Nigeria. Caffeine content was determined by a modification of the methylene chloride-water system method. Results showed significant decreases in the amount of caffeine with increasing levels of infestation, being 8.0 g/kg for uninfested kolanut, 6.5 g/kg For the mildly infested, 6.7 g/kg for the moderately infested, and 4.8 g/kg for the heavily infested. There was no significant difference between the caffeine content of the red and white kolanut cultivars at the two lower levels of infestation. Caffeine content was, however, significantly reduced in kolanuts that were heavily infested with weevils, especially in the red cultivar. Mean reductions in caffeine content ranged from 8.8 to 62.6 % in the red cultivar and from 18.8 to 25 % in the white cultivar.