Study of material transfer during osmotic dehydration of onion slices (Allium cepa) and tomato fruits (Lycopersicon esculentum)

The overall material transfer (water and solubles) was measured during osmotic dehydration of onion slices and tomato fruits in individual and mixed solutions of commercial salt and sugar. The dehydration phenomenon took 20 h in tomato fruits and 15 min in onion slices. The nature of osmotic solution and the treatment time affected the transfer process. A mixed solution of sugar and salt showed the highest dehydration capacity with predominance of water removal and gain of solutes over solute loss. Extended treatment beyond 15 min and 20 h, respectively, for onion slices and tomato fruits, resulted in structural alteration of cells, and increase of exchanges.