Anthocyanin condensed forms do not affect color or chemical stability of purple corn pericarp extracts stored under different pHs.

ABSTRACT

Purple corn is rich in anthocyanins, some of which are condensed with flavanols. The aim was to determine the impact of anthocyanin condensed forms extracted from purple corn pericarp on color and chemical stability at different pHs compared with the complete extract, and an extract without condensed forms. Extracts were dissolved at pH values ranging from 2.0 to 6.0 and stored for 12weeks at 22°C. Color stability of anthocyanins decreased as the pH increased. Slight color differences were observed throughout time at pH 2 (ΔE from 0.2 to 3.6). After 12weeks, pH 6 caused substantial changes in color (ΔE=17.7 to 47.5); and reduced the predicted half-life of total anthocyanins (ranging from 1.8 to 3weeks), compared to pH 2 (44.6 to 60.7weeks). Condensed forms had degradation kinetics similar to monomeric anthocyanins. Purple corn pericarp pigments can be used in acid beverages with an acceptable shelf-life.