Utazi (Gongromena ratifolia) and Nchuanwu (Occimum americanus) were dried using solar dryer and open- air sun drying methods. 200 g of each sample was used. The weight losses were used to determine the reduction in moisture content. Drying was assumed to have taken place in the falling- rate period, which enabled the use of only one drying rate constant, K. Graphs of ln(M0-M) versus time were used to obtain the drying rate constants, K for the two drying conditions. All analyses were done using standard procedures. The drying rate constants for the solar dryer and open- air sun dried Utazi were 0.8 and 0.7, respectively. Similarly, the values for Nchuanwu were 0 2 and 0.3, respectively. Moisture versus time graphs of both samples showed that the assumption of one falling- rate period is justifiable. The solar dryer was more efficient and would be more appropriate to industrial application. Both the nutritional and sensory qualities of the dried products were enhanced by the process.
Key words: Drying, solar dryer, drying rate constant, drying efficiency, nutrients, open-air drying.