Color and stability of 10-catechyl-pyranocyanidins as influenced by C3 substitution patterns, caffeic acid copigmentation, and ascorbic acid degradation
In vitro experimental study demonstrates enhanced pigment stability and ascorbic acid resistance of 10-catechyl-pyranocyanidins, suggesting their potential as stable natural colorants.
Key Points
To evaluate the color characteristics and stability of four 10-catechyl-pyranocyanidins compared to their precursor anthocyanins under caffeic acid copigmentation and ascorbic acid exposure.
Formulated pH 3 aqueous solutions containing four 10-catechyl-pyranocyanidins (PCys) or precursor anthocyanins (ACNs), with and without caffeic acid (CA).
Monitored color and pigment stability of PCy-3-xylglugal-catechol and Cy-3-xylglugal with and without ascorbic acid (AA) during 15 weeks of dark storage at 25°C.
PCys retained 80% to 90% of pigment concentration after 15 weeks of storage, whereas precursor ACNs degraded to 30% to 50% retention.
CA copigmentation caused a bathochromic shift in PCy spectra, reducing color differences relative to precursor ACNs (ΔE decreased from 10 to 5).
PCys exhibited marked resistance to AA degradation, showing a 70-fold increase in half-life compared to the precursor ACN.