Thermodynamic models for water sorption by garlic.

Moisture sorption characteristics of garlic grown in Punjab region of India were evaluated at 20-60(0) C and water activity of 0.2-0.9. The samples were equilibrated using aqueous glycerol solution. Equilibrium moisture content of garlic decreased with an increase in temperature at constant water activity. The data was adjusted to nine sorption models to ascertain the best fit. Comparisons were based on mean relative error, standard error and coefficient of determination. Of the models tested, Oswin model showed best fit. The isosteric heat of sorption decreased with moisture content. Isokinetic temperature and free energy were determined using plots of enthalpy and entropy.