Effect of Drying Temperatures on Drying Kinetics and Lycopene Content of Tomato

Abstract Tomato (Solanum lycopersicum) belongs to the genus Lycopersicon under the Solanaceae flowering plant family. It is a popular vegetable that loses moisture during post-harvest. Hence, developing appropriate post-harvest technology like drying is crucial to extend their shelf life. This study aimed to evaluate the effect of temperatures on drying kinetics and lycopene content of dried tomato slices. The fresh tomato fruits were sliced into 4, 6, and 8 mm thicknesses and dried using a cabinet dryer at 60, 70, and 80 0C. The drying rate kinetics (drying rate, moisture ratio, and diffusivity) were determined and dried tomato was evaluated for lycopene content. This study showed that tomatoes subjected to drying at 70 0C gave the best result. Moisture content decreases gradually with an increase in drying time. Effective moisture diffusivity increased with increase in slice thickness and varied from 2.657 x 10-6 to 6.399 x 10-6 m2/s, 1.723 x 10-6 to 1.140 x 10-6 m2/s, 1.164 to 7.626 x 10-6 m2/s for temperatures 60, 70 and 80 0C respectively. The lycopene content ranged from 3.420 to 6.010 mg/g. The results indicated that a reduction in lycopene content occurred in tomatoes during the drying process. The highest value of lycopene was obtained from a slice thickness of 6 mm at 70 0C while the lowest was obtained from a slice thickness of 8 mm at 60 0C. The most appropriate temperature for drying tomatoes among the monitored temperatures was at 70 ℃ for lycopene content retention.