Effect of the re-use of the osmotic solution on the stability of osmodehydro-refrigerated grapefruit

Abstract

Osmotic dehydration (OD) of grapefruit (55 degrees Brix sucrose solution, 30 degrees C) was carried out to obtain 75 g water/100 g sample in the final product. Although the grapefruit was replaced each time, the osmotic solution (OS) was reused for five OD cycles, with or without pasteurization. The samples obtained in cycles 1, 3 and 5, were stored at 10 degrees C. Changes in degrees Brix, water content, water activity, pH, total acidity, ascorbic acid content, cation concentration, respiration rate and total microbial counts at different storage times were analyzed and compared to fresh-cut grapefruit stored under the same conditions. During OD, a partial loss of the natural soluble substances present in the fruit was observed. In terms of the dehydration level reached by the fruit, it is possible to reuse the OS in up to 5 OD, without any reconcentration treatment. Nevertheless, it is advisable to pasteurize the OS before each cycle in order to obtain a product with a shelf-life of between 7 and 12 days in refrigeration, depending on the number of cycles