Effect of the centrifugal force on osmotic dehydration of potatoes and apples

Abstract

Cylindrical slices (2 cm diameter, 0.5 cm thickness) of potatoes and apples were immersed in three different osmotic solutions: 70% (w/w) sucrose, 30% (w/w) NaCl, and 15% (w/w) NaCl and 45% (w/w) sucrose. Osmotic solutions and food samples were placed into stainless steel containers and centrifuged at 64 × g using a tabletop centrifuge at 30 °C, to perform osmotic dehydration. Results obtained showed that solids uptake by the food samples was always lower when centrifugal force was applied to the system. Under centrifugal force application, and with the osmotic solution containing both NaCl and sucrose, potato slices lost ca. 70% of their original moisture after 6 h of osmodehydration, whereas only 2% of the solutes were taken by the samples. In contrast, osmotic dehydration of static samples for the same time removed ca. 65% of the moisture, but 15% of their original weight was gained by absorption of solids from the osmotic solution. For apple slices, similar results were obtained: 83% water lost, and 6% solids gained for the dynamic system, compared with 75 and 12% respectively, for the static system.