Low-molecular-weight polysaccharide and polyol impregnation enhances the rehydration recovery capacity of freeze-dried potato slices

Fresh fruits and vegetables often undergo irreversible cellular damage during freeze-drying and subsequent rehydration, preventing recovery of their original moisture status, microstructure, and texture. This study investigated the effects of impregnation with low-molecular-weight polysaccharide and polyol protectants, including glucose, trehalose, sorbitol, and glycerol, on the rehydration recovery capacity of freeze-dried potato slices. The rehydrated samples treated with sorbitol exhibited a higher rehydration ratio and moisture content (dry basis), and a moisture distribution more similar to that of fresh samples, as well as lower relative electrical conductivity and improved overall textural properties (hardness and chewiness). Microstructural analyses (by optical microscopy and transmission electron microscopy) and assessment of cell viability (by trypan blue staining) confirmed that sorbitol reduced cell wall and membrane damage in the rehydrated tissues, resulting in a microstructure resembling that of fresh potatoes. These findings provide a basis for using these protectants to improve freeze-dried and rehydrated products.