4. Food processing

4.1 State change diagram

Figure 21 shows the change-of-state curves for pure water at a given pressure and temperature. Water can be in a liquid, solid or gaseous physical state. The figure shows two exceptions:

• when T °C > t critical. Under these conditions, we speak of a supercritical fluid (the liquid and gaseous phases are indistinguishable);

• the triple point: water can be found in all three states (solid, liquid, gas).

Foods are complex heterogeneous matrices that are difficult to characterize....