The specific volumes of extruded amorphous starch and its aqueous mixtures containing up to 30 wt.% were investigated between 25 and 160 degrees C over an extended pressure range up to 100 MPa. The specific volume of water was also measured at the same temperature and pressure range. These highly non-ideal systems develop three-dimensional networks of hydrogen bonds, both in the pure state and in mixtures. The experimental data were correlated with the LFHB (lattice-fluid hydrogen-bonding) model. The model is able to describe satisfactorily the volumetric behavior of both pure components and their mixtures.