Pigments betalains

Beet toots contain both ted pigments (betacyanins) and yellow pigments (betaxanthins), known collectively as betalains. Generally, the betacyanin content of beets fat exceeds that of the betaxanthins. Of the betacyanins present, 75—95% is betanin [7659-95-2] (41) (EEC No. E 162), making it the principal pigment ia beet colorant. 

Betalaines. In 1968, the term betalaines was used to describe collectively two groups of plant pigments the red betacyanins and the yellow betaxanthins. The red and yellow dyes found in beets. Beta vulgaris, fall into this category. An interesting history has been written about these dyes (133). 

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. 

Betalains are vacuolar plant pigments. Hence their hydrophilic nature is comprehensible. Although they are slightly soluble in ethanol and methanol, water is the best snited solvent both for stability and solnbility reasons. In contrast to the antho-cyanins, the betalains are even more polar as can be demonstrated by shorter retention times in RP-HPLC and lower solubilities in alcoholic solutions. The varying polarities may also be beneficially used to separate anthocyanins from betalains on an RP-18 solid-phase extraction cartridge (Stintzing, unpublished data). 

Von Elbe, J.H., Stability of betalaines as food colors, Food TechnoL, 29, 42, 1975. Kimler, L. et al., Betalamic acid, a new naturally occurring pigment, J. Chem. Soc./Chem. Commun., 21, 1329, 1971. 

Wasserman, B.P, Eiberger, L.L., and Guilfoy, M.P., Effect of hydrogen peroxide and phenolic compounds on horseradish peroxidase-catalyzed decolorization of betalain pigments, J. Food Sci., 49, 536, 557, 1984. 

Dhillon, A.S. and Maurer, A.J., Evaluation of betalain pigments as colorants in turkey summer sausages, Poultry Sci., 54, 1272, 1975. 

NON-POLYMERIC N-HETEROCYCLIC PIGMENTS (OTHERTHAN TETRAPYRROLES AND BETALAINS)... 

Several non-polymeric N-heterocyclic pigments other than betalains will be briefly presented in this chapter, even if they do not belong to a unique class of chemical compounds. 

Betalains are water-soluble nitrogen-containing pigments responsible for the red and violet (betacyanins class) and yellow (betaxanthins class) colors found in many flowers, fruits, and occasionally in vegetative tissues of plants of most families of the Caryophyllales order (except the Caryophyllaceae and Molluginaceae families, which have anthocyanins instead)." ... 

Betalains are N-heterocyclic water-soluble pigments deposited in vacuoles. Their common precursor is betalamic acid consisting of a 1,7-diazaheptamethin system, an extended Jt-electron system exhibiting a canary yellow color. Betalamic acid may condense with cyc/o-dopa to yield betanidin, the common precursor aglycon of the red betacyanins. Betanidin in turn may be glycosylated and/or acylated, yielding 29... 

The fortunate constellation of scientists at Wisconsin facilitated further achievements toward increasing pigment content in red beets. In a recurrent selection program, betalain contents of red beet crops were enhanced by 200%. This example should encourage both food scientists and plant breeders to join forces and invest in the improvement of promising color crops. 

Proline, however, is the predominant amino acid and most interestingly, its betalamic acid adduct indicaxanthin is the major betalain pigment in cactus pear. Proline functions as an osmolyte, accumulating in water- and heat-stressed plant tissues, and in comparison to other amino acids, it exhibits an extraordinarily high solubility of 1623 mg/L water at 25°C. ... 

Two main groups can be discerned (1) endogenous factors such as plant enzymes like polyphenoloxidase, peroxidase, and P-glucosidase and (2) conditions prevailing in the extraction medium will decide the fates of betalain pigments among which temperature, oxygen, and pH are considered the most important conditions. 

Besides their interesting color application values, betalainic plants are also worthwhile from a nutritional standpoint. Research on this topic has recently been resumed with great scientific vigor in both in vitro and in vivo studies on red beets, amaranth, red-colored Swiss chard, red-violet pitahayas, and especially cactus pears. ° In the future, betalainic color crops will be benchmarked because of their pigment structure and quantity and also because of the individual and synergistic activities of their components such as colorless phenolics, amino compounds, peptides, proteins, and hydrocolloids. 

Kobayashi, N. et al., Betalains from Christmas cactus. Phytochemistry, 54,419, 2000. Piattelh, M. and Imperato, R, Pigments of Bougainvillea glabra. Phytochemistry, 9, 2557, 1970. 

Gandla-Herrero, F., Carcla-Carmona, R, and Escribano, J., Fluorescent pigments new perspectives in betalain research and applications, Food Res. Int, 38, 879, 2005. Piattelh, M., Minale, L., and Prota, G., Pigments of Centrospermae. III. Betaxanthins from Beta vulgaris L., Phytochemistry, A, 121, 1965. 

Zryd, J.P. and Christinet, L., Betalains, in Plant Pigments and Their Manipulation, Davies, K., Ed., Annual Plant Reviews 14, CRC Press/Blackwell, Oxford, 2004, 185. Gill, M. and Steglich, W., Pigments of fungi (Macromycetes), Progr. Chem. Organic Natural Products, 51, 1, 1987. 

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