Influence of Osmotic Pretreatment on Kinetics of Convective Drying and Quality of Apples

Abstract

This article examines the influence of apple osmotic dehydration (OD) on the kinetics of convective drying and the quality of the products obtained. Fresh apples (Malus domestica), variety Ligol, were used as the experimental material. Samples were first dehydrated in three osmotic agents (glucose, fructose, and sucrose), each at a concentration of 40%, for 30, 60, and 120 min, and then dried convectively. Efficiency of osmotic dewatering was assessed on the basis of water loss (WL) and solids gain (SG). The influence of OD on convective drying kinetics was analyzed by comparing the drying curves and the basic kinetic parameters (time and drying rate). Quality of products was assessed on the basis of colorimetric measurements and sensory evaluation. It was found that OD significantly improved the quality of dried products through better retention of the original color, shape, texture, aroma, and taste, but it did not remarkably affect the rate of convective drying.