pasta, rice, peas, beans and lentils swell in size as their starch granules absorb the water
green vegetables turn bright green for a few minutes, then gradually become dark olive green if overcooked
red / purple fruits and vegetables are affected by acids (makes them a brighter red / purple) and alkalis such as bicarbonate of soda, which makes them turn blue
egg white becomes opaque and yolk becomes lighter in colour as protein denatures and coagulates
