Drying Kinetics and Diffusivity of Osmotically Dehydrated Cherry Tomatoes

Abstract

This paper presents thin-layer drying characteristics and quality of osmotically dehydrated cherry tomatoes. Thin-layer drying was conducted under controlled conditions at the temperatures of 50, 60 and 70C and relative humidity of 10, 20 and 30%. Seven thin-layer models were fitted to the experimental data of thin-layer drying of osmotically dehydrated cherry tomatoes and the Page's model was found to be the best to describe the drying characteristics. The effective moisture diffusivity of osmotically dehydrated cherry tomatoes was also determined. The color of the dried osmotically dehydrated cherry tomatoes was bright reddish brown which was a much better color than the fresh cherry tomatoes and there was no change in color in the temperature range of 50–70C. It is recommended that cherry tomatoes should be dried at 70C in order to achieve efficient drying and good quality of dried products. Practical Applications Cherry tomatoes (Queen cherry) is widely grown in many countries. The amount of cherry tomatoes spoiled during the harvesting season can be minimized by osmotically dehydrating cherry tomatoes to increase their shelf life and to ensure their availability all the year round of cherry tomatoes. In this study, thin-layer drying characteristics of osmotically dehydrated cherry tomatoes are presented under controlled conditions of drying air temperature and relative humidity in search of optimum conditions for osmotic dehydration in terms of efficient drying and good product quality. Thin-layer model developed is also useful in the simulation and optimal design of solar and mechanical dryers for osmotically dehydrated cherry tomatoes.