Understanding of osmotic dehydration on mass transfer and physical properties of freeze‐dried apple slices: A comparative study of five saccharides osmotic agents

Abstract

The aim of this study was to evaluate the effect of five saccharides osmotic agents on the mass transfer kinetics during osmotic dehydration (OD) and freeze-drying kinetics, as well as physical properties of freeze-dried apple slices. The results demonstrated that the water loss (WL) and solid gain (SG) efficiency of the samples osmotic with monosaccharides were higher than that of the disaccharides and oligosaccharide based on k1 of Peleg model (fructose: k1 = 155.0, glucose: k1 = 139.0, sucrose: k1 = 199.0, maltose: k1 = 270.2, and isomaltooligosaccharides: k1 = 351.5). The drying rate of osmotic samples (0.372 g·g−1·h−1 to 0.557 g·g−1·h−1) was lower than untreated sample (0.654 g·g−1·h−1) at the primary drying stage. A significant positive correlation among WL, SG, and hardness (WL: R2 = .888 and SG: R2 = .857) was confirmed. These results suggest that the saccharides are vital determinants for the mass transfer and quality of apple slices, which is meaningful knowledge for developing freeze-dried products with expected texture. Novelty impact statement The osmotic rate and the final solid gain of monosaccharide were higher than disaccharides and oligosaccharides. The primary drying rate of the samples decreased after osmotic process. The water sorption capacity of the samples treated by different osmotic conditions.