Xanthophyll

The most abundant chlorophyll in the leaves masks the colors of carotenoids. When the leaves fall, the most unstable chlorophyll against oxidation breaks down faster and the leaves show the yellowish colors of xanthophiles.

The xanthophyll, xanthophyll or lutein (from the Greek ξανθος, xanthos, 'blonde' and φυλλο, phyllos, 'leaf'; previously, phylloxanthine) is a chemical compound belonging to the group of carotenoids that has one or more oxygen atoms in its structure. In the European Union, the food code for this family of compounds is E-161.

Xanthophylls are pigmented compounds that are found naturally in many plants and also have photosynthetic action. These pigments, more resistant to oxidation than chlorophyll, give dried leaves their yellowish and brownish tones.

Variants

• E-161a Flavoxantina
• E-161b Luteina
• E-161c Criptoxantina
• E-161d Rubixantina
• E-161e Violaxantina
• E-161f Rodoxantina
• E-161g Cantaxantina
• E-161h Zeaxantina
• E-161j Astaxantina

Properties

The xanthophylls are oxygenated derivatives of carotenoids, usually without any activity as vitamin A. Cryptoxanthin is an exception, since it has an activity as vitamin A somewhat greater than half that of beta -carotene.

They abound in plants, being responsible for their yellow and orange coloration, although they are often masked by the green color of chlorophyll. Xanthophylls are also found in the animal kingdom, as pigments in egg yolk (lutein) or salmon meat and in the exoskeleton of crustaceans (canthaxanthin). The latter, when found in crustaceans, sometimes has bluish or green colors, as it is bound to a protein. Heating breaks the union, which explains the color change that some crustaceans experience when cooked. The canthaxanthin used as a food additive is usually obtained by chemical synthesis.

Applications

Canthaxanthin was a basic component of certain types of pills used to get a quick tan. The use of large amounts of these pills led to the appearance of eye problems in some cases, so in some countries there is a tendency to limit the amounts of this product that can be added to food. For example, in the United States the limit is 30 mg/pound.

In Spain, xanthophylls are used for applications similar to those of carotenoids (except in cheese), with the same restrictions.

These colors are of little importance as direct food additives. Only canthaxanthin, red in color similar to that of paprika, is sometimes used due to its greater stability. On the other hand, they are very important as an additive in the feed supplied to trout or salmon raised in fish farms, and also in that supplied to chickens. The objective is to get the meat of the fish or the yolk of the eggs to have a more intense color. The dye used in each specific case depends on the animal species in question, and is usually provided in the form of yeasts of the genus Rhodatorula or as algae Spirulina, rather than as a substance isolated chemistry.