Physical factors such as temperature, moisture and pressure can also cause food spoilage. Physico-chemical reactions are caused by freezing, burning, drying and bruising of fruits and vegetables during storage, handling and transportation, which result in food deteriorations. Food processing or storage causes some deterioration in colour of fruits and vegetables due to the degradation of the chlorophyll resulting dull olive-brown colour. Dehydrated green peas and beans packed in glass containers undergo photo-oxidation and loss of desirable colour occurs. Freezer induced damage observed in frozen foods affects its quality . Anthocyanins, the pigment in fresh and processed foods, form complexes with metals resulting in the change in colour. E.g. Red sour cherries react with tin and form undesirable purple complex. Carotenoid, another colour pigment, degrades by oxidation in the presence oxygen, light and heat.