Color and stability of 10-catechyl-pyranocyanidins as influenced by C3 substitution patterns, caffeic acid copigmentation, and ascorbic acid degradation

The objective of this manuscript was to evaluate color and stability of four 10-catechyl-pyranocyanidins (PCys) compared to their precursor anthocyanins (ACNs). We explored the effects of glycosylation and acylation patterns, copigmentation with caffeic acid (CA), and stability to ascorbic acid (AA) addition. Water adjusted to pH 3 was colored with PCys with or without CA, or with their precursor ACNs. Stability of samples containing 10-catechyl-pyranocyanidin-3-xylosylglucosylgalactoside (PCy-3-xylglugal-catechol) and cyanidin-3-xylosylglucosylgalactoside (Cy-3-xylglugal) with and without AA were also compared. Samples were incubated at 25°C in the dark for 15 w, and color and pigment stability were monitored. PCys were stable throughout storage (80–90% retention after 15 w), while ACN degraded (30–50% retention). Copigmentation with CA caused bathochromic on PCy spectra, decreasing spectral and color differences between PCys and their precursor ACNs (ΔΕ from 10 to 5). The stability to AA-mediated degradation of PCys far exceeded that of the precursor ACN, with a 70-fold increase in half-life.