Impact of gamma-irradiation on some mass transfer driven operations in food processing.

The effect of gamma-irradiation pretreatment on some mass transfer driven operations such as dehydration, osmotic
dehydration and rehydration, commonly used in food processing, was studied. Applied irradiation up to 12.0 kGy
resulted in decrease in hardness of the samples, as indicated by texture analysis. The effective diffusion coefficients of
water and solute determined for dehydration, osmotic dehydration as well as for rehydration using a Fickian diffusion
model. The effective diffusion coefficients for water (in case of osmotic dehydration and dehydration) and solid
diffusion (in case of osmotic dehydration) were found to increase exponentially with doses of gamma-irradiation (G)
according to an equation of the form D ¼ Aexp(�B/G), where A and B are constants. Microstructures of irradiatedcarrot
samples revealed that the exposure of carrot to gamma irradiation resulted in the breakage of cell wall structure,
thereby causing softening of irradiated samples and facilitating mass transfer during dehydration and osmotic
dehydration. The rehydration characteristics showed that gamma-irradiated sample did not absorb as much water as
control, probably due to loss of cell integrity.