Dried yacon with high fructooligosaccharide content

Abstract

The convective drying of yacon was investigated (40–70°C). Pulsed vacuum osmotic dehydration (PVOD) (sorbitol 38 °Brix, 35°C, 681 mmHg in the first 10 min) as pretreatment was tested. Drying behavior, energy consumption, diffusivity, fructooligosaccharide (FOS) retention, shrinkage, water activity, shrinkage, and color were measured. Fick's model was adequate for drying kinetics adjustment, mainly for untreated samples with shrinkage consideration. PVOD pretreated dried yacon was a less shrunken product in a shorter drying time with up to 60% FOS retention. Nevertheless, the best tested condition for FOS retention (88%) was the convective drying at 60°C without PVOD application.

Practical Applications The yacon is a seasonal plant that presents high concentrations of functional compounds. Like most vegetables, its shelf life is short and storage difficult. Therefore, improved techniques for conservation are required. The present paper evaluates the effects of drying temperature on the production of fresh and osmodehydrated yacon slices during convective drying. This study could offer an interesting response to the changes promoted by these processes, relating to the modifications to the physicochemical properties of osmodehydrated yacon.