As natural colorants

As for anthocyanins, betalains are found in vacuoles and cytosols of plant cells. From the various natural sources of betalains, beetroot (Beta vulgaris) and prickly pear cactus (Opuntia ficus indica) are the only edible sources of these compounds. In the food industry, betalains are less commonly used as natural colorants from plant sources than anthocyanins and carotenoids, probably related to their more restricted distribution in nature. To date, red beetroot is the only betalain source exploited for use as a natural food coloring agent. The major betalain in red beetroot is betanin (or betanidin 5-0-P-glucoside). Prickly pear fruits contain mainly (purple-red) betanin and (yellow-orange) indicaxanthin and the color of these fruits is directly related to the betanin-to-indicaxanthin ratio (99 to 1, 1 to 8, and 2 to 1, respectively in white, yellow, and red fruits)." ... 

Studies of the stability and stabilization of anthocyanins are still required, based on the extreme importance of those pigments for food colors. Modem HPLC-MS equipment also allows us to easily follow the copigmentation reactions in detail, calculate their kinetic and thermodynamic parameters, identify the products formed during the reactions, and thus shed new light on the stability and stabilization of these pigments. Since anthocyanins play important roles as natural colorants for... 

Genomic and molecular tools have made great impacts on plant biotechnology and offer potential for manipulation of carotenoids as natural colorants and also for applications in human and animal health. While microbial and other non-plant systems have been successfully used, plant modification eliminates need for expensive bioreactors and offers economically feasible opportunities for less developed nations for production of nutraceuticals and other chemical products. 

The phycobiliproteins are accessory photosynthetic pigments aggregated in cells as phycobilisomes that are attached to the thylakoid membrane of the chloroplast. The red phycobiliproteins (phycoerythrin) and the blue phycobiliprotein (phycocy-anin) are soluble in water and can serve as natural colorants in foods, cosmetics, and pharmaceuticals. Chemically, the phycobiliproteins are built from chro-mophores — bilins — that are open-chain tetrapyrroles covalently linked via thio-ether bonds to an apoprotein. ... 

The EU directive includes a list of colorants (coded as E numbers, from E 100 to E 180) suitable for use as food additives and specifies limits of impurities. For details about their codes, sources, and properties see Table 7.2.1. An update of EU legislation on food-related issues was published recently. In addition to the numbered E colorants, other new natural colors for use in the future as natural colorants are under examination (see positions 25 through 34 in Table 7.2.1). ... 

Mortensen, A. (2006). Carotenoids and other pigments as natural colorants. Pure Appl. Chem. 78, 1477-1491. 

Voile N, Challier L, Burr A, Giulieri F, Pagnotta S, Chaze A-M (2011) Maya Blue as natural coloring fillers in a multi-scale polymer-clay nanocomposite. Compos Sci Technol 71 1685-1691... 

Anthocyanins from various berry sources are a very interesting group of colored pigments of the flavonoid family as they serve as natural colorants and as functional food ingredients. 

Anthocyanins are a group of plant phenolics characterized by their blue-orange-red color. They have a double interest as plant constituents, one technological, since they can not only be used as natural colorants in the food industry but also can interact with other plant components influencing the final characteristics of the processed product, and the other is related to their implications on human health as they can be considered functional ingredients and have shown themselves as potential targets for the pharmacological industry. 

On the other hand, polyphenols have many industrial applications, being used as natural colorants and preservatives in cosmetic or food industry [6]. 

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