Obtaining sorption isotherms from ginger subjected to osmotic dehydration with sucrose and maltitol

Ginger is a perennial plant whose rhizome constitutes the part of greatest interest, because it is rich in nutraceutical compounds and because of its pungency. One of the main problems faced is the high perishability of the rhizome, due to its high moisture content. Thus, the combination of osmotic dehydration pretreatment followed by drying has proven to be an effective strategy to reduce its deterioration.  The determination of water sorption isotherms is essential to optimize the processing and storage of ginger. Thus, the objective of this study was to present the sorption isotherms of ginger after the osmotic dehydration process, using saturated solutions of sucrose and maltitol, at temperatures of 20 and 40°C. The osmotic dehydration process was carried out at 25°C, using a ratio of 1:50 (mass/mass) of ginger and saturated solution. Subsequently, the isotherms were obtained by static gravimetric method, using thirteen saturated saline solutions. The experimental results were adjusted to the Oswin, Peleg, Henderson and GAB models. The equilibrium moisture content showed a decreasing trend with increasing temperature, ranging from 0.3475 to 0.0032 g of water/g of dry matter for sucrose treatment and from 0.3823 to 0.0037 g of water/g of dry matter for maltiol treatment. The experimental data showed a better fit to the GAB model, with RAdj² ≥0.993, RMSE ≤0.008 and ꭓ²≤6.087.10-5