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Turmeric with BioPerine Supplements

Turmeric Health Benefits and Culinary Uses

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De methoxycu rcumin

De methoxycu rcumin bis- Demethoxycurcumin

FIGURE 9.8 Coloring compounds in turmeric products. (Adapted from Govindarajan.43)

bis- Demethoxycurcumin

FIGURE 9.8 Coloring compounds in turmeric products. (Adapted from Govindarajan.43)

benzene; soluble in methyl and ethyl alcohols, glacial acetic acid, and in propylene glycol; very soluble in acetone and ethyl ether. Curcumin is also sold as a salt — a finely ground powder — as globular radiating flame-colored crystals. This salt is insoluble in ether, but soluble in alcohol and water.

2. Chemistry of Turmeric Color

The yellow color is the principal functional property of turmeric. The main compounds involved in color are curcumin, demethoxycurcumin, and bisdemethoxycur-cumin (Figure 9.8).43 Pigments have been separated by HPLC in a reverse-phase Zorbax-C18 column and identified by their visible and fluorescence spectra. The three curcuminoids also exhibit fluorescence under ultraviolet and, after separation on thin-layer plates, can be directly estimated by fluorescence densitometer when irradiated at 350 nm; the fluorescence spectra of the curcuminoids show distinct excitation at 435 nm, and emission at 520 nm.42-44

Estimation of total curcuminoids is done on the alcoholic extract of the powdered rhizome by measurement of optical density at their absorption maxima, 420 to 425 nm. In the Eiserle procedure, 5 mg of oleoresin are dissolved in 100 ml, absorbance is evaluated at 422 nm, and A422 is multiplied by 2000 to give the "color value." In contrast, turmeric powders are characterized by analytical and subjective values (Table 9.7).43

Three components, curcumin, demethoxycurcumin, and bisdemethoxycurcumin, have been estimated by TLC separation to be present in the ratio 60:30:10, 49:29:22,

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