This invention provides an apparatus for simulating digestion of a foodstuff, which apparatus comprises: (a) an outer containment vessel into which fluid can be introduced and removed via at least one orifice, and (b) an inner digestion chamber comprising a rigid portion (240) through which the foodstuff can be introduced and a flexible portion (250) which tapers from the rigid portion to an aperture (260) from which the foodstuff can be removed wherein said inner chamber is se.chi.urable within the outer vessel such that reversible alteration of fluid pressure within the outer vessel causes reversible partial compression of the flexible portion for mixing foodstuff present therein. Also provided is an apparatus for simulating mechanical digestion of a foodstuff, which apparatus comprises: (a) an outer cylinder (534) including in a first end wall an entry port through which the foodstuff can be introduced, and at the opposite second end an opening for receiving an inner cylinder (532), and in the side wall proximal to the first end wall an exit port from which the foodstuff can be removed, (b) an inner cylinder (533) slidably mounted within the outer cylinder and including in a first end wall an aperture through which the foodstuff can be reversibly forced between the inner and outer cylinders, and at the opposite second end an opening for receiving a plunger, and (c) a plunger slidably (530) mounted within the inner cylinder for drawing the foodstuff through the entry port and aperture into the inner cylinder, wherein the aperture is within a resilient diaphragm secured within the end wall of the inner cylinder, and wherein the volume of the inner cylinder is between 20 and 200 ml. The invention also provides systems and methods for simulating digestion of a foodstuff.