Infrared Drying of Banana Slices: Quality Evaluation Using Spectral and Microstructural Analysis

This study evaluates the drying kinetics of banana slices sliced at various infrared powers and measurable values, as well as the spectral and microstructural changes that some physical quality parameters present. Banana slices were dried at 300, 400, and 500 W (894, 1190 and 1410 W/m2 infrared radiation intensity) medium wavelength infrared (MWIR). In addition, banana samples were sliced to be 6–8 and 10 mm. The drying processes were terminated when the samples reached approximately 30% moisture level. After drying, banana samples’ quality values, such as color, shrinkage, and water loss were evaluated. FT-NIR (Fourier Transform-Near Infrared) spectroscopy and microstructure measurements were performed. For banana slices dried at different powers with medium-wavelength infrared, the shortest drying time is for 6 mm thick products and can be operated in the range of 33–36 min−1. When the color values were examined, it was determined that the lowest total color changes occurred at 500 W drying power. In shrinkage measurements, samples dried at 500 W power were observed at the highest frosting. In water loss analyses, statistically similar results were obtained at 500 W drying power for various thicknesses. While the microstructural configurations of sliced banana samples were observed to be smoother during drying, samples dried at 300 W power were detected in a tighter form during drying and they were combined more regularly at 500 W power. FT-NIR spectral measurements were again expressed independently of the reflection values due to the wide pore range in high-power infrared drying (500 W).