The acylated, B-ring substituted anthocyanins of Trudescantiupallidu (TPA) were extracted from the leaves with acidic water, purified on a Duolite-861 resin and incorporated into a model beverage. The beverage was composed of a citrate-phosphate buffer at pH values 3.5, 4.5 or 5.5, and 15% sucrose. Comparison samples contained cyanidin-3-glucoside from blackberries and a commercial sample of enocyanin from grapes. The TPA samples were much more stable than the other two, particularly at the higher pH values as judged by pigment retention and tristimulus color readings. The extra absorption band of the TPA samples at pH 5.5 indicated the samples were well colored.Addition of tannin and/or ascorbic acid resulted in marked pigment and color loss.
The anthocyanin pigments of red sweet potato roots (Impomoea batatas) were isolated, purified and identified by HPLC and conventional paper chromatographic, spectral and chemical methods. Two major pigments and two minor pigments were present in fresh tissue slices extracted with boiling 1% HAc methanol. Tissues extracted cold yielded 11 or more pigments probably from degradation of the two major pigments. One major pigment was identified as peonidin-3-diglucoside-5-glucoside with three molecules of ferulic acid and one molecule of caffeic acid. The other major pigment was peonidin-3-diglucoside-5-glucoside with two molecules of ferulic acid and one caffeic acid.
The Trudescantiu pallida anthocyanins were about 29 times more stable in a nonsugar drink model system than red cabbage (Brussica 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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.