Effects of Storage on Nutritional, Mineral Composition and Mycoflora of Stored Sundried Citrullus lanatus Thunberg (Melon) Seeds

Abstract

The effect of storage on the nutritive values, proximate composition and mycoflora of Citrullus lanatus was investigated during a 24 weeks of storage. The mycoflora were isolated using direct plating and washing methods. Eight fungi were isolated namely Fusarium sp., Rhizopus sp., Mucor sp., Aspergillus niger, A. fumigatus, A. flavus, Penicillium chrysogenum and Penicillium sp. The fungal count was found to increase as the storage time increased. The proximate analysis showed a decrease and an increase on some parameters investigated. The mineral composition was found to decrease as the storage time increased. The following nutrients (g/100 g) were found to have reduced: ash content 4.29 - 3.19, fibre content 2.06 - 1.51, fat content 57.02 - 50.90, while the following increased: Moisture content 7.21-12.22, crude protein 29.24-30.90, carbohydrate content 0.20-2.01. The results for minerals analysis (mg/100 g) showed a decrease in all parameters investigated: sodium 2.01-1.49, potassium 65.52-56.21, calcium 13.10-10.19, magnesium 46.34-37.61, Iron 8.12-3.31, zinc 4.76-1.24, copper 2.84-2.11 and phosphorus 3.46-1.60 while lead and cadmium were not detected. However, storage was found to cause deterioration and reduction in the nutritive value and mineral content of C. lanatus seeds. It is therefore recommended that these seeds must be stored under controlled conditions that will prevent the growth of fungi and reduction of nutrients.