Water sorption of food models for studies of glass transition and reaction kinetics

Applicability of a method for studying glass transition and reaction rates was evaluated. Water sorption of maltodextrin and poly(vinylpyrrolidone) based food models having lysine and xylose as reactants were determined gravimetrically at 4 temperatures. Data were modeled using the Guggenheim-Anderson-DeBoer (GAB) equation, isosteric heats of sorption were calculated, and water activity shift with temperature was evaluated using the Clausius Clapyeron equation and the GAB equation that included the effect of temperature (the GAB (T) equation). Within a 100 degreesC temperature range, water activity shift with temperature could not solely explain different reaction rates. Storage of food models in sealed containers can be applied in studies of glass transition and reaction kinetics.