Glycosides changed the stability and antioxidant activity of pelargonidin

Abstract Pelargonidin glucosides represent important pigments in the food industry. We compared the pH, metal-ionic, and thermal stability of pelargonidin (Pg), pelargonidin-3-O-glucoside (P3G), pelargonidin-3-O-rutinoside (P3R), and pelargonidin-3,5-O-diglucoside (P35DG) using visible spectrum analysis at 400–700 nm. The results showed that the pH stability of P3G and P3R exceeded Pg and P35DG. Ferrous ion (Fe2+) enhanced the stability of P3G and P3R, while thermal processing-induced degradation was evident in Pg and pelargonidin glycosides, according to the 1.5-order kinetic equation. Moreover, Pg and P35DG displayed higher temperature sensitivity than P3G and P3R. Then, 2,2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity and ferric reducing antioxidant power (FRAP) analysis of the chemical models, and cell activity and reactive oxygen species assays of Caco2 and human umbilical vein endothelial cells (HUVECs) were used to identify the relationship between the pelargonidin structure and antioxidant activity. The DPPH-scavenging activity and FRAP values increased when the number and molecular weight of the pelargonidin glycosides were reduced, increasing the pro-oxidant properties in the Caco2 cells and the antioxidant activity in the HUVECs. Accordingly, this study suggested that glycosides might enhance the stability while decreasing the antioxidant activity of pelargonidin since glycosides increase the steric hindrance during reactions.