Effect of pre-drying treatment, drying and rehydration on plant tissue properties: A review

Abstract

The paper presents the effect of pre-drying treatment, drying and rehydration on plant tissue properties. Pre-drying procedures are divided into chemical and non-chemical treatments. The effect of sulphur dioxide, calcium and sodium chlorides on plant tissue and its behavior during drying and rehydration is discussed. Sugars, organic acids, biopolymers and surface active agents are also used to pretreat plant material before drying. Sugars at low and high concentrations as compounds modifying plant tissue properties are thoroughly discussed. Blanching and freezing are pre-drying treatments which strongly affect tissue properties. Blanching at low and high temperature affects tissue properties in a different way. The effect of drying on plant tissue properties is discussed under the following headings: shrinkage, porosity, biopolymer structure, and biochemical activity. Rehydration following drying to plant material. Water imbibition causes swelling and build up of swelling stresses. The damage to the tissue structure due to pre-drying treatment and drying results in limited water absorption and intense solubles leakage.