Reuse of sorbitol solution in pulsed vacuum osmotic dehydration of yacon (Smallanthus sonchifolius)

Abstract

The osmotic solution (OS) used in pulsed vacuum osmotic dehydration (PVOD) could represent an environmental problem. The reuse of the solution minimizes the cost, but has to consider the properties of the dehydrated product and the solution itself. The reuse of sorbitol solution, 38 kg/100 kg solution, in 15 successive PVOD of yacon slices (35°C, 300 min) was studied. The evaluation was based on alterations of soluble solids, water activity, pH, turbidity, electrical conductivity, viscosity, density, color, and microbiological stability. The weight loss, moisture content, and soluble solids of the food were also evaluated. Among the OS characteristics, only the color, electrical conductivity, and turbidity of the solution changed significantly, alterations that could be reduced with filtration. The food properties were not significantly affected. The microbiological content was retained in acceptable levels. The reuse of the sorbitol solution could be performed without relevant alterations in the food or the solution. Practical applications The osmotic solution is used in osmotic dehydration to promote a partial removal of the moisture content of the food. However, after the osmotic process, the solution is diluted and contains native solutes from the food. For obtaining a dehydrated product within a standard production, the solution should also present standard characteristics. This works presents the evolution of some analysis as soluble solids, water activity, pH, turbidity, electrical conductivity, viscosity, density, color, and microbiological stability in a solution of sorbitol. Sorbitol solution is an alternative to sucrose for obtaining semidehydrated products with glycemic index. It was shown that the solution could be used for at least 15 times in yacon dehydration.