Classification of Food Colours

Chlorophyll pigments in dehydrated vegetables are unstable during processing and storage. Although heat during blanching and drying initiates some degradation, the major deterioration during storage of dehydrated vegetables is mainly due to light exposure, which triggers photooxidation.

This reaction leads to:

• Breakdown of chlorophyll molecule
• Formation of dull-colored compounds (pheophytins and chlorophyllides)
• Loss of bright green color → turning olive-brown or yellowish

Light accelerates oxidation reactions, especially in the presence of oxygen, making dehydrated vegetables more susceptible during shelf life if not properly packaged (e.g., transparent packaging increases damage).