Solar Tunnel Drying: Pretreatment on drying kinetic of plum tomatoes

Abstract

Drying of thin layer tomato was studied using a solar tunnel dryer under the ecological conditions of Isparta, Turkey. During drying process, solar irradiation, drying air temperature, relative humidity, and air velocity were measured constantly in different parts of the dryer. Drying runs were performed using plum tomatoes, characterized by an oval shape, intense red color. The change of tomatoes mass was measured daily. The color measurements of dried products were determined at the beginning and end of experiment. In this study, the fresh tomato samples were sorted, graded, washed in water and then sliced into quarters and halves before pretreated. Sun drying behavior of half and quarter sliced tomatoes pretreated with 10% NaCl solution and non-pretreated was investigated. Results showed that the drying time for pretreated and non-pretreated samples was not significantly different. However, drying time and drying rates were affected by number of tomato slices (quarter and half). Drying characteristic curves were evaluated against thirteen mathematical models and the Midilli et al model was the best descriptive model for solar tunnel drying of thin layer tomato. Color analysis emphasized that if tomatoes are pretreated with 10% NaCl solution, they should be sliced in quarter for better quality.

Recent Developments in Design and Operations of Solar dryer.

“…The experimental analysis of drying grapes made the pre-treatment by washing the grapes sample with portable water and then dipping the grape in a hot water bath, followed by cooling the grape in cold water [29]. The fresh tomatoes were first sorted, graded and washed in water in the Karaaslan et al [30] study. Then it was cut into quarters and halves followed by pre-treated with 10% NaCl solution.…”