Dry Rot of Raphia hookeri and its Effect on Proximate Composition of the Fruits

Abstract

Postharvest dry rot of Raphia hookeri palm fruits was studied and found to be caused by Xylaria feejeensis. Also associated with this fungus were Penicillium dierckxii, Botryodiplodia theobromae, Aspergillus niger and Trichoderma sp. The disease caused dryness of the fruits, thereby affecting the testa and embryo and making the fruit unsuitable for planting. Proximate analyses of the healthy and infected mesocarps of the fruit was carried out using the methods described by the Association of Official Analytical Chemists, revealed the presence of food components such as moisture, ash, fibre, protein energy fat and minerals. The results of the proximate and mineral composition of infected fruits showed decreases in all the food and mineral components apart from ash and magnesium which increased from 4.33% to 6.10% and 395.6ppm to 1538.93ppm, respectively. There was also a significant decline in the phosphate and zinc content which decreased from 1165.6pp to 65.31ppm and from 10.45ppm to 0.825ppm, respectively. The decrease in the moisture content, food and mineral contents and increase in ash indicate the utilisation of these components by the microorganisms. The result of the proximate and mineral composition shows that R. hookeri fruit contains high amounts of mineral elements required for good health and fitness in man, therefore adequate and proper care of the fruit during harvesting and storage should be ensure for proper conservation of these nutritional components.