Secagem convectiva da batata yacon em formato de cilindro.

Abstract

The potato yacon (Smallanthus sonchifolia) is originally from the Andes and was brought to Brazil for cultivation. It became popularly known as the diet potato because it is rich in fructooligosaccharides (FOS) and inulin. These constituents have a beneficial effect on health because they have low caloric value and contribute to reducing cholesterol and glucose. The objective of this work was to dry the yacon potato in a cylindrical format in a fixed bed dryer at different temperatures (50, 60 and 70 ºC) and drying air velocities (1.0, 1.5 And 2.0 m/s). The yacon potato in natura was characterized regarding its physical, chemical and physicochemical parameters. The Page, Henderson & Pabis, and Two terms diffusion approximation models were adjusted to the drying kinetics data, and the shrinkage coefficient and effective diffusivity were determined. The dry yacon potato was characterized physically, chemically and physico-chemically and its moisture adsorption isotherms were determined at 25 °C and adjusting the GAB, Oswin and Peleg models to the experimental data. Potato yacon in natura has been found to have low acidity and starch content, and is a source of antioxidants and minerals. The temperature and the drying air velocity influenced the effective diffusivity and the shrinkage, resulting in an increase in these measurements with the increase of these parameters. The dry samples showed low water activity, increased sugar concentration, phenolic compounds and antioxidant capacity, as well as a tendency for browning during drying. It was found that the GAB, Oswin and Peleg models can be used to estimate the moisture adsorption isotherms and were classified as type II and III.