Effects of Different Drying Methods on Physico-Chemical and Microbial Properties of Tomato (Lycopersicon esculentum Mill) var. Roma

摘要

Different drying methods (sun drying, solar drying and oven drying at 50, 55 and 60°C) were evaluated for their effects on the quality of tomato (Lycopersicon esculentum Mill) var. 'Roma'. A fresh sample served as control. The fresh and dried tomatoes were evaluated for changes in total solids, ash content, titratable acidity, pH, lycopene, total carotenoids, ascorbic acid and total microbial and fungi count. The results of the total solids and ash content showed that sun-dried tomatoes had the lowest total solids (89.6%) and mineral retention was highest in the solar-dried samples (2.6%). The contents of ascorbic acid were significantly (P<0.05) reduced after drying from 27.3 nig/100 g in the control sample to 11.4, 7.9 and 5.3 mg/100 g in sun-dried, solar-dried and 60°C oven-dried, respectively. Tomatoes dried in the oven had a significantly lower amount of ascorbic acid when compared to sun- and solar-dried tomatoes. There was a considerable increase in the carotenoids and lycopene contents ofthe dried samples. Carotenoids were best retained in samples dried at 60°C, and lycopene content was higher in tomatoes dried in the solar dryer. Tomatoes dried in the oven at 60°C had the least aerobe and fungal counts, which were higher in sun-driedsamples.