Quality evaluation and drying kinetics of shitake mushrooms dried by hot air, infrared and intermittent microwave-assisted drying methods

The aim of the study was to conduct comparative analyses on drying kinetics, color, rehydration ratio, polysaccharide content and aromatic components composition of shitake mushrooms dried by using hot air drying, infrared drying and intermittent microwave assisted hot air drying. Intermittent microwave assisted drying resulted in greatly reduced drying time and higher drying rate in comparison with the other methods. The highest polysaccharide content (240.28 mg/100 g) was achieved when microwave-assisted drying was used. Furthermore, microwave-assisted drying showed its predominance in the categories and amount of generated nitric aroma (1.17%) during drying, and it could be a method for improving fresh like characteristics of dried vegetables due to the moderate level of aldehydes (0.26%) and ketones (4.22%) formed during drying. Shitake mushrooms treated with hot air drying showed the greatest amount of sulfuric aromatic compounds (7.7%) and the highest rehydration ability as well as a lower total color difference in the cap. Therefore, shitake mushrooms dried by hot air or combined with microwave should be considered due to their enhanced physical properties or chemical components.