Effect of Harvesting Stage and Drying Method on Cowpea Leaf Nutrient Composition

Cowpea leaves are lost annually due to infestation and spoilage when being transported to clients and the losses at the local markets are brought on by inadequate postharvest handling procedures and market glut, particularly during peak seasons. High moisture content from the cowpea leaves at harvest stage may contribute to increased spoilage hence lowering quantity and quality. The choice of appropriate harvesting stage and drying method can help to reduce this problem. The aim of this study was to determine the best harvesting stage and efficient drying method that would maintain high leaf nutrient composition. Cowpeas variety M66 was used for the research and the treatments included three harvesting stages (21, 35 and 49 days after sowing [DAS]), three drying methods (open sun, solar dryer and oven. Data was collected on iron, calcium, crude fibre, beta carotene, protein and moisture content. The data was subjected for variance using Statistical Analysis System 9.2 edition and significantly different means separated using least significant difference at 5%. The results indicated significant (p<0.05) differences in moisture, calcium, proteins, beta carotene and crude fibre content in both trials. Harvest stage and drying method did not significantly (p<0.05) influence the iron content. Oven and solar drying methods showed better nutrient and mineral retention in the three harvesting stages when compared to the open sun drying method.