Stability of anthocyanins of Sambucus canadensis and Sambucus nigra

Elderberry anthocyanins (Sambucus nigra) including acylated derivatives (Sambucus canadensis) were studied for use as beverage pigments. Cyanidin 3-O-(6-O-E-p-coumaroyl-2-O-beta-D-xylopyranosyl)-beta-D-glucopyranoside-5-O-beta-D-glucopyranoside from S. canadensis was more stable than cyanidin 3-sambubioside from S. nigra. Acylation improved both heat and light stability, whereas glycosidation only stabilized anthocyanins in the presence of light. Cyanidin 3-(E)-p-coumaroyl-sambubioside-5-glucoside changed to three new anthocyanins under light irradiation. These three anthocyanins were isolated, and their structures were identified to be cyanidin 3-O-(6-O-Z-p-coumaroyl-2-O-beta-D-xylopyranosyl)-beta-D-glucopyranoside-5-O-beta-D-glucopyranoside, cyanidin 3-O-(6-O-E-p-coumaroyl-2-O-beta-D-xylopyranosyl)-beta-D-glucopyranoside, and cyanidin 3-O-(6-O-Z-p-coumaroyl-2-O-beta-D-xylopyranosyl)-beta-D-glucopyranoside.