ABSTRACT
Recently, interest in the application of natural pigments to replace synthetic dyes in beverages has grown. The present study investigates the stability of anthocyanin-rich grape and purple sweet potato (PSP) extracts to photo- and thermostresses in ready-to-drink (RTD) beverage models including hot fill beverages with various concentrations of ascorbic acid, a preserved beverage, and a vitamin-enriched water beverage. Thermo- and photostresses were induced at 40, 60, and 80 °C and 250, 500, and 750 W/m(2), respectively. Qualitative and quantitative data on anthocyanin content were collected by pH differential assay and LC-MS. Increasing concentration of ascorbic acid caused more rapid degradation through thermostress, but had a protective effect through photostress. Additionally, PSP was significantly less stable than grape extract in the vitamin-enriched water model beverage through photostress. Furthermore, photostress caused the formation of monoacylated peonidins from diacylated peonidins.