Combined effect of γ-irradiation and osmotic pretreatment on mass transfer during dehydration

The combined effect of gamma-irradiation (3.0-9.0 kGy) and osmotic pretreatment (10 and 50 degrees B) on dehydration kinetics was studied. The exposure to irradiation pretreatment resulted in an increase in cell wall permeabilization, leading to softening of tissue, which in turn resulted in faster dehydration. The effective diffusion coefficient of water in case of potato during dehydration, considering Fickian diffusion, increased from 2.38 x 10(-9) to 4.14 x 10(-9) m(2)/s at 9.0 kGy, whereas the osmotic pretreatment resulted in lower dehydration rates due to infusion of solute from osmotic solution, which resulted in lower mass transfer rates. Even though the effective diffusion coefficients decreased from 2.38 x 10(-9) to 1.55 x 10(-9) m(2)/S (Up to 50 degrees B), the osmotic pretreatment improves nutritional, sensorial and functional properties of food without changing its integrity, apart from partial removal of water present in food. The combining of y-irradiation treatment with osmotic pretreatment resulted in increased mass transfer rates during air dehydration, offering a feasible solution for satisfactorily enhancing the mass transfer rates. (c) 2005 Elsevier Ltd. All rights reserved.