Natural pigments anthocyanins

Delgado-Vargas, R, Jimenez, A.R., and Paredes-Lopez O., Natural pigments carotenoids, anthocyanins, and betalains — characteristics, biosynthesis, processing, and stability, Crit. Rev. Food Sci. Nutr., 40, 173, 2000. 

Fernando and Senadeera [40] used different natural pigments incorporating anthocyanins that were extracted from various tropical flowers. The extract was acidified to p H < 1, assuming a deeper coloration, and was used for the preparation of the photovoltaic apparatus. The generation at pH <1 of the oxonium ion allows the wide conjugation of the Jt-electron density throughout the aglycone portion of the... 

Juices extracts (liquorize), spirits (orange, lemon), syrups (black currant), tinctures (ginger), and aromatic waters Mineral pigments (iron oxides), natural colorants, anthocyanins, carotenoids, chlorophylls riboflavine, red beetroot extract, and caramel synthetic organic dyes azo compounds... 

The discussion above has addressed the assessment of a product s colour or perceived colour in basic terms. In the next two sections, methods to determine which coloured compounds are present in a product will be addressed. For the purpose of this chapter, the section on synthetic dyes will cover the analysis of the water-soluble dyes, or so-called coal tar dyes, and the section on natural pigments will cover the anthocyanin pigments, such as grape skin extracts, and the carotenoid-based materials, even if they are of synthetic origin. 

Matsui, T, Ueda, T., Oki, T., Sugita, K., Terahara, N., and Matsumoto, K., alpha-Glucosidase inhibitory action of natural acylated anthocyanins. 1. Survey of natural pigments with potent inhibitory activity J. Agric. Food Chem., 49, 1948-1951, 2001. 

Anthocyanins are a proanthocyanidin-type of flavonoid distributed in various fruits. These anthocyanins are the most important visible plant pigments in the natural kingdom. Anthocyanins have been clinically used in many folklore medicines worldwide for the treatment of age-related diseases and other disease. This review presents the functionality of anthocyanins in relation to their chemistry, synthetic pathway, antioxidant activity, antitumor activity (including apoptosis-inducing activity), pharmacodynamics (absorption, metabolism, distribution, and excretion) and toxicity, and discusses their possible use as food and dietary supplements and usage in potential nutraceuticals. 

DELGADO-VARGAS, F., JIMENEY, A. R. and PAREDES-LOPEZ, O. (2000). Natural Pigments Carotenoids, Anthocyanins and Betalains - characteristics, biosynthesis, processing and stability. Critical Reviews in Food Science and Nutrition 40 (3) 173-289. 

Some of these phenolic compounds are directly related to colours in plants, and in particular anthocyanidins ate natural pigments present as anthocyanins in plant tissues in glucoside forms with a C6-C3-C6 skeleton. Only a few phenolic compounds absorb tight in the visible range and anthocyanins are the only significant subgroup of polyphenols visible to the human eye (Brouillard et al. 

Identification and Assignment of Structure The identity of a synthetic product is often established by comparison of its absorption curve with that of the natural product or another standard sample. The absorption curves of synthetic and natural vitamin A2 are shown in Figure 7.1. The identification pf coloured substances is easier since colour can almost always be correlated with the presence of certain types of chromo-phoric groups. Thus, visible absorption spectra are employed for the detection and identification of the natural pigments (e.g. carotenoids, anthocyanins md porphyrins), dyes and other colouring matters. Hie absorption spectra of these colouring principles will be discussed separately in Chapter 12. 

The use of natural pigments for food applications is gaining soil from day to day [95]. Curcumin, betaine, amarathine, anthocyanins and P-carotene are the most common and widely used pigments [95,96], Saffron s coloring properties attributed mainly to water-soluble carotenoids are used for coloring of foods. The stability of these saffron pigments in aqueous... 

A number of anthocyanins are used as food additives (Harbome and Grayer, 1988 Strack and Wray, 1989 Tim-berlake and Henry, 1988). Anthocyanins also are important in that they control the marketability and taste properties of many commercial products. The sale price of many fruits and vegetables is dependent on full color development. Some major commercial sources of these natural pigments are grapes (Vitis vinifera), roselle (Hibiscus sabdarijfa), blueberries (Vaccinium spp.), and red cabbage (Timberlake and Henry, 1988). 

Besides silica, other direct phase supports such as alumina, diatomaceous earth, cellulose, MgO-diatomaceous earth, and sucrose layers were employed for the separation of various pigment mixtures. Mixed-mode supports (cyano, diol, and aminosilica layers) were also employed in both the direct and reversed-phase elution modes for the separation of natural pigments, but their performance was markedly lower that those of traditional silica layers. Reversed-phase supports (polyamide, octadecylsilica, alumina, sihca, and diatomaceous earth impregnated with paraffin oil) were also applied for the separation of color pigments (carotenoids from Capsicum annuum, anthocyanins from red wines) and it was found that their separation... 

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