Pigments in vegetables and fruits
Vegetables and fruits are appealing because of their bright and variable colours which are due to pigments present in the plastids of plant cells. The chief pigments of vegetables and fruits can be classified as water soluble and fat soluble.
Chlorophyll is the green pigment of leafy vegetablesandothergreencolouredvegetables like capsicum, beans, peas and chillies. It is mostly insoluble in water. Two cholorophylls have been isolated. Cholorophyll-a is intense blue green in colour and cholorophyll- b is dull yellow green in colour.
Carotenoids are the yellow, orange, red fat soluble pigments distributed in nature. They are divided into three groups viz. carotenes present in carrot, green leafy vegetables and other fruits, lycopenes present in tomatoes and xanthophylls present in yellow fruits.
Pigments that contain the phenolic group include anthocyanin, anthoxanthin, leuco anthoxanthin, catechin,quinones and betalins. The first four groups are collectively known as “Flavanoids”.
They are a group of reddish water- soluble pigments occurring in many vegetables and fruits. Cherries, red apples, pomegranates have their colour appeal due to anthocyanins.
They are colourless white to yellow pigments that give colour to cauliflower, onions, spinach or other leafy vegetables. In green leafy vegetables the colour is masked by chlorophyll.