Color and Microstructure Properties of Tomatoes Dried by Microwave, Convective, and Microwave-Convective Methods

In this study, color and microstructure changes of tomato samples were investigated after microwave (90, 160, 350, and 500W), convective (50 and 75 degrees C), and microwave-convective (90W-50 degrees C, 90W-75 degrees C, 160W-50 degrees C, and 160W-75 degrees C) drying treatments using a laboratory microwave-convective oven. The combined microwave-convective drying decreased the drying time required when compared to drying with either convective or microwave drying alone. The color of the samples dried at 50 degrees C was closest to the fresh samples compared to other drying conditions. All color values of fresh tomato were affected by drying. Scanning electron microscopy images showed that disruption of the tomato samples significantly elevated with increasing drying temperature or microwave power level.