Changes in maize starch water sorption isotherms caused by high pressure


  • The affiliation was affiliated formerly to José Ferreira.


The effect of high pressure (300 MPa, for up to 60-min duration) on water sorption (adsorption and desorption) properties of maize starch suspensions was studied. Increase in the pressurisation time (5–60 min) augmented linearly the water-holding capacity of starch by 2.7-fold. Adsorption and desorption isotherms moved to higher moisture contents with the increment of pressurisation time. These movements caused the hysteresis effect extent to decrease/increase with the pressurisation time for lower/higher water activity values. While no particular tendency was found for the effect of pressurisation time on energy-related constants, Cb (BET) and Cg (GAB), the K value decreases linearly, being always higher for sorption. The monolayer value obtained using the BET model was lower compared with the GAB model, increasing linearly in both cases with the pressurisation time. The results obtained in this study are of possible technological importance for food products containing starch.