Influence of Process Conditions on the Kinetics of the Osmotic Dehydration of Yacon (Polymnia sonchifolia) in Fructose Solution

Yacon is a tuberous root with functional properties that contains near 90% water, promoting its quick degradation. The purpose of this work was to optimize the osmotic dehydration of yacon using response surface methodology (RSM). Water loss, solute gain and water activity were determined as functions of the independent variables such as temperature (30-50C), fructose concentration (40-68% w/w) and use of an edible sodium alginate coating coverage. Correlation equations were constructed describing the effects of the independent variables. By applying RSM, the optimum conditions for dehydration were found to be with sodium alginate coating in a solution at 68 degrees Brix and 30C for 60min. Practical Applications The process of osmotic dehydration can be used for the preparation of shelf-stable products for the purpose of obtaining a more physicochemically and microbiologically stable final product. The treatment of coating before osmotic dehydration helps in reducing the problem of large solute gain without affecting much on the water loss. The fruits obtained by combining coating and osmotic dehydration exhibit better appearance and extended shelf life. The product can be used in the areas of nonavailability of fruit, and it is also used as an ingredient in the formulation of products such as jellies and yacon syrup.