Pigment extraction

Qumones are colored p benzoqumone for example is yellow Many occur natu rally and have been used as dyes Alizarin is a red pigment extracted from the roots of the madder plant Its preparation from anthracene a coal tar derivative m 1868 was a significant step m the development of the synthetic dyestuff industry... 

Carmine is a colored pigment extracted from the female insect Coccus cacti or Dactylopius coccus, or its eggs. These insects live on prickly pear cactus in Mexico. The Spanish conquistador Hernan Cortes brought the dye to Europe after seeing the Aztecs use it. 

Efforts have been made to reduce the production costs of fermentation pigments compared to costs of synthetic pigments and pigments extracted from natural... 

The microalgae are cultured in bioreactors under solar or artiflcial light in the presence of carbon dioxide and salts. The bioreactors may be closed systems made of polyethylene sleeves rather than open pools. Optimal conditions for pigment production are low to medium light intensity and medium temperatures (20 to 30°C). Pigment extraction is achieved by cell breakage, extraction into water or buffered solution, and centrifugation to separate out the filtrate. The filtrate may then be partly purified and sterilized by microfiltration and spray dried or lyophilized. 

To minimize the decomposition of pigments, the nse of milder pigment extraction procedures has been proposed. This involves nsing weaker and volatile organic acids such as formic, acetic, citric, or tartaric acids or small amounts (0.01 to 3%) of stronger more volatile acids snch as trifluoroacetic acid, which could be then removed during pigment concentration. s concentrations on the order of 0.01 to 0.05% and... 

Figueiredo, P. et al., Anthocyanin intramolecular interactions a new mathematical approach to account for the remarkable colorant properties of the pigments extracted from Matthiola incana, J. Am. Chem. Soc., 118, 4788, 1996. 

A pigment extract of the yellow mutant of Chlorella shows an absorption spectrum with peaks at 370 and 450 nm, which could be attributed to a carotenoid and a purely UV-absorbing pigment103). 

Carotenoids were discovered during the nineteenth century. Wachen in 1831 proposed the term carotene for the hydrocarbon pigment crystallized from carrot roots Berzelius called the more polar yellow pigments extracted from autumn leaves xanthophylls and Tswett separated many pigments by column chromatography and called the whole group carotenoids. ... 

Pigment extraction is carried out with acetone and methanol. After evaporation of the combined extracts under reduced pressure, the pigments are separated on a Partisil-10 stationary phase with a mobile phase consisting of light petroleum (bp 60-80 °C), acetone, dimethyl sulfoxide and diethylamide (75 23.25 1.5 0.25 by volume). When chlorophyll c is present, a further develop-... 

There are commonly accepted experimental standards for the determination of conductivity and specific resistance in aqueous pigment extracts [18]. The electrical conductivity y is calculated from the electrical conductance its inverse is the specific resistance f=l/-y, derived from the electrical resistance. Additional experimental methods have been developed for the determination of soluble sulfates, chlorides, and nitrates [19]. 

From the user s point of view, the ability of a pigmented system to withstand exposure to water, alkali, or acids is frequently of more importance than an evaluation of pigment extracts. 

Fig. 2.132. Chromatogram of spinach, stored frozen until analysis by HPLC (A) and after acidifying the same pigment extract with 0.2ml M HC1 per 10 ml extract and exposure to air and light for 15 h at 20°C (B). Zinc-phtalocyanine was used as an internal standard (IS). Peak identification 1 = chlorophyll-b 2 = chlorophyll-a x = unknown degradation product 3 = IS 4 = pheophytin-b 5 = pheophytin-a 6 = chlorophyll-b 7 = chlorophyll-a 8 = pheophytin-b 9 = pheophytin-a. Reprinted with permission from T. Bohn et al. [303].

Fig. 2.133. HPLC chromatogram of pigment extracts from table olives cv. Gordal (a) healthy fruits and (b) altered fruits. Peaks 1 = 15-glyoxilic acid pheophorbide-b 2 = 15-glyoxilic acid pheophorbide-a 3 = Cu-15-glyoxilic acid pheophorbide-a 4 = pheophorbide-b 5 = pheophorbide-a 6 = pyropheophorbide-a 7 = 15-glyoxilic acid pheophytin-b 8 = Cu-15-glyoxilic acid pheophytin-b 9 = 15-glyoxilic acid pheophytin-a 10 = Cu-15-glyoxilic acid pheophytin-a 11 = 15 -OH-lactone-pheophytin-b 12 = 15 -OH-lactone-pheophytin-a 13 = 15-formylpheophytin-b 14 = pheophytin-b 14 = pheophytin-b 15 = 15-formylpheophytin-a 16 = pheophytin-a 16 = pheophytin-a 17 = pyropheophytin-b 18 = Cu-pheophytin-a 19 = Cu-15-formylpheophytin-a 20 = pyropheophytin-a 21 = Cu-pyropheophytin-a. Reprinted with permission from B. Ganul-Rojas el al. [304].

COMPARISON OF TLC Rv VALUES OF THE RED PIGMENT EXTRACTED FROM LARVAL GANGLIA AND FROM THE EGGS OF B. MORP... 

Pepper breeders are interested in making carotenoid-rich peppers not only for higher vitamin A content but also for use in red pigment extraction. The red pigments are extracted as an oleoresin and used as a natural colorant. This dye is used in a variety of products ranging from cosmetics to food coloring [24]. 

Ionic Iron Levels in Beef Pigment Extracts, and Thiobarbituric Acid Values Obtained on Heating Extracts with Washed Beef Muscle°... 

For comparison, total iron (heme + nonheme) in fresh meat pigment extracts was 20.64 /ng/g meat. Adapted from Igene et al. (1979). 

The electrical conductivity (or resistivity) of an aqueous pigment extract is determined from the electrical conductance (or resistance). For standards, see Table 1 ( Resistivity ). Apparatus centrifuge with glass containers, resistance measurement bridge, electrolytic cell. 

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