Drying kinetics and quality of tomato fruits dehydrated by a vacuum-microwave method

We applied vacuum-microwave drying (VMD) to tomato fruits and examined its effects on drying rate and fruit qualities in comparison with two conventional techniques; microwave drying (MD) and hot air drying (HAD). The changes in moisture content, surface color, and nutritional components of the fruit samples during the drying process using VMD, MD and HAD were measured. The drying rate constant in the VMD was greater than that in both the MD and the HAD. Lycopene and antioxidant activity were observed at higher level in the samples dried by the VMD, compared to those dried by the MD and the HAD. The VMD samples were considerably light in color, while the MD and HAD dryings resulted in a dark color of samples. From these results, VMD was found to be more suitable and useful to get high-quality dried fruits than MD and HAD.