Assessment of convection, hot-air combined with microwave-vacuum and freeze-drying methods for mushrooms with regard to product quality

P>Combined drying of hot air and microwave-vacuum has been proposed as an alternative method to improve the quality of dried mushrooms, especially the structural and textural properties. In the present study, the effect of different drying methods namely, convective hot-air drying, hot air combined with microwave-vacuum drying and freeze-drying on qualitative attributes of pretreated mushrooms was investigated. The quality assessment was based on colour, texture, density, porosity and rehydration characteristics of the dried mushrooms. Combined drying of hot air and microwave-vacuum resulted in a dried product of superior quality when compared to the slices dried completely by conventional hot air, exhibiting lower overall colour variation, higher porosity, greater rehydration ratio and softer texture. In a dry state, mushrooms with a puffy structure and unique crispy texture were created by the combined drying method, which might be considered as important characteristics for developing nonfat snack-type food products.