Stability of Anthocyanins from Tradescania pallida

The acylated, B‐ring substituted anthocyanins of Tradescantia pallida (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.