Drying of tomato slices using solar drying method

Abstract

Tomato is a fruit with various benefits that has been used widely either for household needs or industries. However, it is easily spoiled if not treated correctly due to its high moisture content. In this experiment, a newly-designed solar dryer with automatic data measurement system was applied for tomato slices drying, along with sun drying method as a comparison. After that, the profile analyses of drying temperature, solar intensity, relative humidity, moisture content, and drying rate as well as quality analyses were carried out to assess the performance of the solar dryer. The initial moisture content of tomato slices was 90% wet basis and dried until it reached between 25-50% wet basis. From the experiment, it was found that solar dryer was much faster compared to sun drying. The final moisture content at the top, middle, and bottom tray of solar dryer was 28.57%, 43.18%, and 57.98%, which fulfilled the standard value. Faster drying of tomato slices was observed at the top tray, mainly because it was the first tray to receive solar radiation. From quality analyses, it was found that vitamin C content of dried tomato slices was lower compared to the fresh ones. Dried tomato slices’ cell wall was more fragile, while the brightness of tomato slices increased when dried using solar dryer. These results proved that solar dryer is indeed a viable method for tomato slices drying, although several drawbacks from quality analysis should be addressed in the future by optimizing the dryer or the drying procedure.