OSMOTIC DEHYDRATION OF APPLES - SHRINKAGE PHENOMENA AND THE SIGNIFICANCE OF INITIAL STRUCTURE ON MASS-TRANSFER RATES

The existence Of two well-defined structures in the parenchymatic tiss ue of apples (the flesh) gave us the opportunity to study the signific ance of the initial structure oil mass transfer rates of two apple var ieties, Kim (Sweden) and Granny Smith (Argentina) when subjected to os motic dehydration. Our results verified the importance of the initial structure for osmotic processing responses. Knowledge of the propertie s of the tissue and the solution penetration into the intercellular sp ace, permitting rw to explain the kinetics found. Shrinkage properties such as volume changes, bulk density, particle density and porosity, have been studied macroscopically for both structures, inner (close to core) and outer (close to skin) and presented as a function of water content in a manner similar to air drying practice. A comparison with shrinkage properties observed in air drying is attempted. (C) 1998 Els evier Science Limited. All rights reserved.