Osmotic dehydration progression in apple tissue I: spatial distribution ofsolutes and moisture content

Atmospheric osmotic dehydration experiments were carried out with apple (Gr anny Smith var.) slices (20 and 30 mm thick) and sucrose-water osmotic solu tions, 65% (why), at different temperatures (20 degrees C, 30 degrees C, 40 degrees C and 50 degrees C). After treatment, serial cuts, 1.5 mm thick, w ere obtained to determine water and sugar content profiles. Values of diffu sion coefficients were obtained in situations of developed and non-develope d profiles. An 'advancing disturbance front' mechanism was proposed. The re sults showed that full development of concentration profiles takes several hours depending on temperature and sample thickness (more than 34 h for a s ample of 30 mm thick at 30 degrees C). (C) 1999 Elsevier Science Ltd. All r ights reserved.