Anthocyanins are found in a wide range of flowers, fruits and vegetables and are responsible for their red to purple colours. The shades exhibited by anthocyanins are dependent on pH, with the colour changing from red through purple to blue as pH increases. As a result, when using anthocyanin colour, it is important to know the pH of the food product that is being coloured. Anthocyanin-based colours are more stable below pH 4 and is often used in acidic food. Anthocyanin pigments are water soluble and are able to withstand short periods of moderate heating.