Abstract
This work aimed to study the rehydration characteristics of vacuum freeze- (VFD) and hot air-dried (HAD) garlic slices and explain the rehydration mechanism. It was observed that VFD samples had significantly faster water absorption rates than HAD samples. However, VFD samples had lower final moisture contents than the HAD samples. Additionally, the effect slice thickness on rehydration characteristics of samples was lower than that of drying methods. The contact angle and microstructure analysis of dried samples revealed that the strong water wettability and the porous structure contributed to the faster water absorption rate of VFD samples. Moreover, we found and confirmed, for the first time, that numerous air bubbles trapped in the VFD samples hindered the absorption of water. This resulted in a lower water holding capacity in VFD samples compared with HAD samples, which had less air bubbles.
•Rehydration characteristics of dried garlic slices were studied.•Vacuum freeze-dried samples showed a faster water absorption rate.•Hot air-dried samples obtained the highest moisture content after rehydration.•The strong water wettability and porous structure promote the water absorption.•Air bubbles trapped in the tissue reduce the water holding capacity of samples.