Osmotic dehydration kinetics of fresh and frozen blueberries considering volume shrinkage in a novel ternary solution

Abstract

Osmotic dehydration is a nonthermal processing technology, that is limited in blueberries because of the osmotic agent, temperature and efficiency. This study was to prepare a novel ternary solution considering low-sugar, low-salt and low-viscosity requirements and to dehydrate blueberries at 20 °C. The mass transfer kinetics of fresh and frozen blueberries were explored in ternary solution considering the volume shrinkage of blueberries. The results showed that the 40%/50% xylitol solution had the lowest viscosity in polyols at 20 °C. The addition of 5%/10% CaCl 2 had no significant effect on the viscosity of the ternary solution. Frozen blueberries had higher OD efficiency and less equilibrium time than fresh blueberries at 600 rpm vibration speed and 50%xylitol/10%CaCl 2 concentration. There was competition between xylitol and CaCl 2 transfer at shorter dehydration times for fresh blueberries, which was not significant in frozen blueberries and with longer times. Considering volume shrinkage of the blueberries, the effective diffusion coefficient of water and solute was calculated. The vibration speed had a significant effect on the effective diffusion coefficient, which governed the mass transfer efficiencies of the blueberries in the ternary solution.

The Influence of Polyols on the Process Kinetics and Bioactive Substance Content in Osmotic Dehydrated Organic Strawberries

“…There are seven polyols which are defined as nutritive sweeteners according to the European Union legislation, i.e., sorbitol, mannitol, isomalt, maltitol, lactitol, xylitol and erythritol [28]. Recently, researchers have focused on the use of erythritol [22,[29][30][31][32], xylitol [21,22,24,31,32] and maltitol [21,22,24,31,32] as osmotic agents, whereas there are few studies concerning the application of sorbitol [33,34], mannitol [35], isomalt [32] and lactitol in the OD process. Sorbitol and mannitol are six-carbon polyols that have the same molecular weight of about 182 and differ only in the position of the hydroxyl group on carbon 2 in the molecule.…”