Anthocyanins of Tradescantia pallida. Potential Food Colorants

Tradescantia pallida (syn. Setcreaseapurpurea) contained two major anthocyanins. One was cyanidin-3,7,3¹-triglucoside with 3 molecules of ferulic acid and an extra terminal glucose. The other pigment was similar but without the terminal glucose unit. The nonacyl portion was indentified by comparison with the pigment of Zebrina pendula. The acyl/aglycone and acyl/sugar ratios were determined by using internal standards and response factors with HPLC. The pigments may have potential as food colorants.     

Quantitative Comparison of the Stability of Anthocyanins from Brassica oleracea and Tradescantia pallida in Non-Sugar Drink Model and Protein Model Systems

The Tradescantia pallida anthocyanins were about 29 times more stable in a nonsugar drink model system than red cabbage (Brassica oleracea) anthocyanins, and 15 times in a fish protein system. The degradation of the anthocyanins from both sources in a nonsugar drink model was logarithmic rather than linear. The mechanism for logarithmic relationship was assumed to be the difficulty of water molecules diffusion to the hydrophobic center formed by the acyl groups and the aglycone.     

Quantitative Methods for Anthocyanins. 4. Determination of Individual Anthocyanins in Cranberry and Cranberry Products

SUMMARY– A new method was developed to determine the quantities of the four major anthocyanins in cranberry and cranberry products. The pigments were streaked on Whatman No. 1 paper and separated by multiple ascending chromatography with 1-butanol-benzene-formic acid-water (100:19: 10:25). The individual bands were measured by transmission densitometry at 525 nm. The ratio of individual pigments was calculated from the densitometric peak areas. The linearity of densitometric response for anthocyanins was established. The amount of each individual anthocyanin present was calculated from the total anthocyanin content and the ratio of individual anthocyanins. The reproducibility of the methods was 6% for the two arabinosides and 4 to 5% for the two galactosides expressed as the coefficient of variability.     

Stability of Anthocyanins from Sweet Potatoes in a Model Beverage

Model beverages containing a citrate-phosphate buffer at pH 2.8, 13% sucrose, and a colorant were stored at room temperature for 1 yr in the dark. The colorants consisted of pigment extracts from red sweet potatoes, the same extract with the acyl groups removed, cyanidin-3-glucoside from blackberries, and a commercial sample of enocyanin from grapes. The sweet potato pigments were the most stable, closely followed by those from blackberries. The deacylated samples and those containing enocyanin were much less stable, as judged by color measurements and pigment analyses.     

Major Anthocyanin from Tradescantia pallida: Identification by LSI-MS and Chemical Analyses

The structure of the main anthocyanin from Tradescantia pallida was identified by LSI mass spectrometry and HPLC as cyanidin-3,7,31-triglucoside with three molecules of ferulic acid, one molecule of caffeic acid and one terminal glucose.