Obtenção de abacaxi seco por processo combinado de desidratação osmótica e secagem convectiva.

Abstract

The aim of this work was to obtain dehydrated pineapple using combined process of osmotic dehydration and convective air-drying. For the osmotic dehydration a ternary solution (water + sucrose + maltodextrin) was used. The effect of temperature (43.2–76.8°C), sucrose (43.2–66.7%) and maltodextrin (0–10%) concentration on responses of weight and moisture loss, solid gain and solid/water loss were investigated. Complete experimental design 23, with central and axial points were used. The influences of the independent variables and its interactions on the responses were analyzed through variance analysis (ANOVA), test F and determination coefficient (R2). It was verified that the input variable studied showed significant effect on the responses of the osmotic dehydration. The mathematical models obtained were considered predictive for the osmotic dehydration. For the convective airdrying it was chosen the best condition for the samples osmotically dehydrated, with respect to relation between solid gain/moisture content losses. The best condition was at 60oC with sucrose and maltodextrin concentration of 55 and 5%, respectively. The convective air-drying of samples with and without osmotic treatment were done in an oven with forced air circulation at 50, 60 and 70oC and air-drying velocity of 2 m s-1. The mathematical models of Lewis, Henderson & Pabis and Page were applied to describe the behavior of the experimental data. According of obtained results the osmotic treatment and the increase of temperature showed a great influence on the convective air-drying of samples. The final product was assessed by means of physical chemical analysis of moisture content, pH, total reducing sugar, total soluble solids, acid value, ashes and sensory analysis of acceptance. The osmotically dehydrated samples dried at 70°C showed the best sensory analysis.