Evaluation of the effects of different drying methods on quality of NASPOT13 sweet potato variety

Abstract

Postharvest handling of sweet potato through drying has persistantly remained a big issue on maintaining sweet potato quality. Direct sun drying is the oldest method of food preservation practiced by mankind. A major disadvantage associated with direct sun drying is that it takes long time even at high temperature, which may cause serious damage to the flavor, colour, & nutrients in dried products, it is also associated with problems like contamination by foreign materials, dirt, dust and wind-blown debris and insect infestation as well as uneven drying. The study therefore assessed the effect of different drying methods on the quality of NASPOT13 sweet potato variety, different samples of the sweet potato were subjected to sun drying, oven drying, and solar drying. After drying, the samples were anlysed for Vitamin C, Vitamin A, and Total Soluble Solid, and moisture content across all the drying methods. Sensory evaluation was also conducted to asses’ acceptability. The results of this study revealed that the ascorbic acid, vitamin A, and Total Soluble Solid (TSS) content varied significantly due to the effect of the different drying methods. Sundried orange flesh sweet potato had the highest ascorbic acid content of 5.962 mg/100g Dry Weight (DW) and least is oven dried orange flesh sweet potato with 0.892mg/100g DW dry weight. Meanwhile solar dried orange flesh sweet potato had significantly the highest content of vitamin A of 40.15mg/kg dry weight than that dried under sun drying and oven drying with 34.44mg/kg dry weight and sun drying with 35.00mg/kg dry weight. On the other hand, TSS content was observed to be highest in the solar dried orange flesh sweet potatoes with TSS content of 2.2% followed by sun dried orange flesh sweet potatoes with 2.060% content of TSS and oven dried OFSP had the least with 1.91%. Therefore, the study concludes that using solar drying is the most essential method of processing orang fleshed sweet potato in maintaining the quality of Orange flesh sweet potato as compared to oven drying.