Secagem e caracterização do parênquima do cladódio da palma

Abstract

The forage palm has a great advantage because it is a cactacea well adapted to the climatic adversities of the Northeast region, easy to plant and high dry mass production per hectare. The objective of the present work was to dry the parenchyma of the palm cladode (Opuntia fícus-indica L. Mill) by combined processes of osmotic dehydration and convective drying. The parenchyma was cut into cubes and subjected to osmotic dehydration in sucrose solutions (brown sugar and crystal sugar) with two concentrations (45 and 55 oBrix) at a temperature of 50 °C, then subjected to convective drying at temperatures of 55 and 65 oC. It was found that the kinetics of water loss and solids gain during osmotic dehydration with the two sucrose solutions can be predicted by an exponential equation; and convective drying kinetics can be estimated by the Page and Midilli models, with the best fit for the Midilli model. The osmoconvectively dehydrated samples showed the best values for water activity, total titratable acidity, ascorbic acid, moisture content, ash, carotenoids, phenolic compounds, flavonoids, anthocyanins and redness for samples treated with brown sugar when compared with brown sugar samples treated with crystal sugar. The Peleg and GAB models can be used to estimate the moisture adsorption isotherms of the dehydrated osmodhydrated samples, with emphasis on the Peleg model resulting in the best adjustments. Most moisture adsorption isotherms were classified as type III.