Influence of humectants on the drying kinetics, water mobility, and moisture sorption isotherm of osmosed air-dried papaya

Papaya slices were sequentially soaked in 40, 50, and 60 degrees Brix sucrose solutions. There was a higher water loss and solids gain when 60 degrees Brix sucrose solution was partially substituted with 10% (w/v) sorbitol, 10% (v/v) glycerol, or invert sugar. The modified Henderson and Pabis model provided the best fit to experimental drying kinetics. Moisture sorption isotherm of all dried papaya, at 30 +/- 2 degrees C, was a type III with different curvature, revealing different sugar-binding ability towards water molecules. The Henderson model showed suitable fit to experimental desorption isotherm data. NMR water mobility revealed the better ability of glycerol to bind water than sucrose.