In this study, sweet potato and pumpkin were pre-treated and dried to obtain ready-to-eat products. Four different pre-treatments were performed as follows, untreated as control (A), dipping in boiling water (B), dipping in 15% sugar solution at 70ºC (C) and dipping in 1% sodium metabisulphite solution (D). These pre-treatment samples were dried with different drying methods. These methods include solar drying, sun drying and oven air drying. The maximum temperature difference between inside and outside solar dryer was as high as 21.8 º C. Likewise, the inside relative humidity is lower than the outside solar dryer and maximum differences were as high as 19.4%. Solar drying period for all tested samples ranged between 52 to 58 hrs with 8-12% moisture content, while 63 to 97 hrs were needed to dry all tested samples by sun drying to reach the same moisture content. On the other hand, oven air dryer required only 6 hours for all tested samples.
Data given in this study showed the effect of pre-treatment, drying methods and storage period at ambient temperature for 6 months on moisture content, total sugars, reducing sugars and acidity as citric acid of dried samples. Results showed that pretreatment sample with 15% sugar solution and sodium metabisulphite increased water removal in all samples. Data represent indicated that more total sugars and reducing sugars were observed in untreated samples for all drying method. Also, data obtained showed that more increasing in acidity for samples were treated with sodium metabisulphite compared with the other samples. Solar drying was observed to product relatively better product in terms of nutrient composition compared to sun drying. Drying was faster with the use of the solar drier than sun drying. Solar drying produced samples with lower moisture content. Organoleptic evaluation of the dried samples was also performed, including of color, taste, odor, texture and acceptability.