Ascorbic, isoascorbic, metaphosphoric, and gluconic acids improved the regeneration of red beet juice pigments after heating, and resulted in greater retention of the pigments during processing and storage. Their effect varied depending on the pH of the juice solutions. Ascorbic and isoascorbic acids allowed for the greatest regeneration at pH 3.8. At pH 6.2, metaphosphoric acid and gluconic acid were more effective. Addition of ascorbic acid once prior to the first heating retained the initial concentration of pigments even after 5 cycles of heating (3 min at 100°C) and regeneration. Control solution lost red pigments completely.
Crude anthocyanins extracted from grape skin were solubilized in hexane containing 100 mM bis(2-ethylhexyl)sodium sulfosuccinate (AOT) by forming stable reverse micelles (RMs). Anthocyanins solubilized in RMs showed about four times greater color intensity than that in aqueous medium. The color intensity of anthocyanins in RMs was primarily affected by the interaction between sulfonate head of AOT and flavylium cation of anthocyanins. The molar ratio of water to AOT (Wo) also influenced the color properties. As the Wo increased from five to 20, the color intensity increased and resulted in a bathochromic shift. This result suggests that increased micelle size facilitates complexation between AOT and flavylium cation. The color stability of anthocyanins in RM was higher than that of buffered anthocyanins during the storage at 30 degrees C. The current study might be utilized as a model system to predict color properties of anthocyanins in apolar medium.
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.