Drying of tomato pretreated with calcium

Pieces of tomato pericarp were pretreated by soaking in CaCl2 solution before convective drying. Drying was interrupted at prescribed water contents and volume of the piece, its area, perimeter and shape factor were measured. It was found that pretreatment cause shrinkage of tomato pieces by some 15%. Drying causes further shrinkage, which in both nontreated and pretreated tomato is larger than the volume of evaporated water. Microscopic examination showed that pretreatment of tomato with calcium ion causes larger tissue structure alterations in comparison to those observed in nontreated tomato. Calcium concentration gradients cause variable resistance of the tissue to deformation. During dehydration tissue is torn apart and large cavities are formed. It results in faster drying of pretreated tomato in comparison to drying of nontreated tomato.