THEORETICAL DETERMINATION OF SORPTION ISOTHERMS APPLIED TO PROCESS CHESTNUT WITH OSMOTIC PRE-TREATMENTS BASED ON ITS CHEMICAL COMPOSITION

Abstract

Sorption isotherms for fresh chestnut and particularly processed chestnut with osmotic treatments using sodium chloride, glucose and sucrose solutions of different concentrations (22.0%, 56.5%, and 60% w/w, respectively) were predicted at 25°C by means of a simplified prediction algorithm of water sorption isotherms. This model is based on the composition of the main compounds of foods (glucose, fructose, sucrose, salt, protein, fibre and starch). The processed chestnut composition changed significantly by the addition of salts and sugars. The processed chestnut sorption isotherm was theoretically predicted with the same accuracy as the chestnut fresh isotherms. Using the prediction model the equilibrium moisture content could be calculated for the assayed systems with a correlation coefficient (R 2 ) of (>0.989), a mean relative error (E) of (<4.40%) and a standard error (E RMS ) of (<0.049 kg (kg d.b.) -1 ).