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Any of a class of yellow, orange, red, and purple pigments that are widely distributed in nature. Carotenoids are generally fat-soluble unless they are complexed with proteins. In plants, carotenoids are usually located in quantity in the grana of chloroplasts in the form of carotenoprotein complexes. Carotenoprotein complexes give blue, green, purple, red, or other colors to crustaceans, echinoderms, nudibranch mollusks, and other invertebrate animals. Some coral coelenterates exhibit purple, pink, orange, or other colors due to carotenoids in the calcareous skeletal material. Cooked or denatured lobster, crab, and shrimp show the modified colors of their carotenoproteins.

The general structure of carotenoids is that of aliphatic and aliphatic-alicyclic polyenes, with a few aromatic-type polyenes. Most carotenoid pigments are tetraterpenes with a 40-carbon (C40) skeleton. More than 300 carotenoids of known structure are recognized, and the number is still on the rise.

There are several biochemical functions in which the role of carotenoids is well understood. These include carotenoids in the photosynthetic apparatus of green plants, algae, and photosynthetic bacteria, where carotenoids function as a blue light-harvesting pigment (antenna or accessory pigment) for photosynthesis. Thus carotenoids make it possible for photosynthetic organisms more fully to utilize the solar energy in the visible spectral region. See Chlorophyll, Photosynthesis

Another function of carotenoids is to protect biological systems such as the photosynthetic apparatus from photodynamic damage. This is done by quenching the powerful photodynamic oxidizing agent, singlet oxygen, produced as an undesirable by-product of the exposure of pigmented organisms to light.

Perhaps the most important industrial application of carotenoids is in safe coloration of foods, as exemplified in the coloring and fortification of margarine and poultry feedstuff.

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.


A class of labile, easily oxidizable, yellow, orange, red, or purple pigments that are widely distributed in plants and animals and are preferentially soluble in fats and fat solvents.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Maize provitamin A carotenoids, current resources, and future metabolic engineering challenges.
The main type of maize consumed in Africa is white maize, with a low level of provitamin A carotenoids [5].
During both milling and processing, biofortified maize hybrids showed good levels of retention of provitamin A carotenoids when using apparent retention values [21].
Stored vitamin A will help meet your needs when intake of provitamin A carotenoids or vitamin A is low (19, 20).
Provitamin A carotenoids such as beta-carotene are generally considered safe because they are not traditionally associated with specific adverse health effects.
[54.] Pixley K, Palacios N, Babu R, Mutale R, Surles R and E Simpungwe Biofortification of maize with provitamin A carotenoids. In: SA Tanumihardjo [Ed.].
[130.] Englberger L, Aalbersberg W, Ravi P, Bonnin E, Marks GC, Fitzgerald MH and J Elymore Further analyses on Micronesian banana, taro, breadfruit and other foods for provitamin A carotenoids and minerals.
Therefore, it is important to identify the concentration of the provitamin A carotenoids (pVACs), specifically beta-carotene, a-carotene and beta-cryptoxanthin, in plant material.
As discussed in the previous section, a 15 [micro]g/g (ppm) dry weight of provitamin A carotenoids (beta-carotene equivalents) breeding target was set (Table 8.1).
Orange-fleshed sweet potatoes (OFSP) contain high levels of beta carotene, an important provitamin A carotenoid [2-5].