Table 6.
Classification of natural colorants according to chemical functional groups (structure) [279,282,287].
| Chemical Class | Example of Class | Source | Color Produced | |
|---|---|---|---|---|
| Quinones | benzoquinone | 1,4-benzoquinone | Pyrus lindleyi | brown |
| anthraquinones | alizarin | Rubia tinctiorum | red | |
| napthoqinones | lawsone (2-hydroxy-1,4-naphthoquinone) |
Lawsonia inermis | brown, purple grey and shades of orange |
|
| juglone (5-hydroxy-1,4-naphthoquinon) |
Juglans regia | |||
| Polyphenols | flavones | luteolin | Reseda luteola | yellow and brown |
| apigenin | Chamomilla recutita | |||
| chrysin | Passiflora incarnata | |||
| anthocyanins | protocyanins | Centaurea cyanus | red, violet or blue (depending on pH) | |
| malvidin, peonidin, delphinidin | Althaea rosea | |||
| 3-delphinidin sambubioside (hibiscin), 3-cyanidin sambubioside, 3-delphinidin glucoside | Hibiscus sabdariffa | |||
| 3-cyanidin glucoside (chrysanthemum), 3-cyanidin sambubioside |
Sambucus nigra
fructus |
|||
| Betalains | betacyanins | betanin |
Beta vulgaris
Amaranthus cruentus Opuntia ficus-indica |
red and purple |
| betaxanthins | vulgaxanthin I and II, indicaxanthin |
Hylocereus polyrhizus, Opuntia ficus-indica, Beta vulgaris |
yellow and orange | |
| Carotenoids | carotenes | α-, β-, γ-carotene, lycopene |
Daucus carota, Solanum lycopersicum, Sorbus aucuparia |
orange, red and yellow |
| xanthophylls | lutein, zeaxanthin, violaxanthin | Spinacia oleracea, Zea mays, Tagetes erecta |