Effect of maltodextrin and gum arabic on water sorption and glass transition temperature of spray dried chicken meat hydrolysate protein

The water adsorption isotherm and glass transition temperatures (T-g) of chicken protein hydrolysate powder, with and without maltodextrin or gum Arabic, were studied in order to investigate their stability. The hydrolysate powder, pure and formulated with 10%, 20% and 30% (w/w) of additive, was obtained by spray drying. The sorption isotherm was determined by the gravimetric method. A differential scanning calorimeter was used to determine the T-g of samples equilibrated with several water activities. As results, the BET model fitted the data for the sorption isotherm of the protein hydrolysate well. A strong plasticizing effect of water on the T-g was found, with a great reduction in this value with increase in water activity. The data for T-g versus solids content gave a satisfactory correlation with the Gordon-Taylor model. The addition of carrier agents increased the T-g of the hydrolysate, decreasing its hygroscopicity and, consequently, increasing its storage stability. (C) 2008 Elsevier Ltd. All rights reserved.