Effect of chlorogenic acid on spectral properties and stability of acylated and non-acylated cyanidin-3-O-glycosides

• Published in: Food chemistry Vol. 240; pp. 940 - 950
• Main Authors: Gras, Claudia C., Bause, Karola, Leptihn, Sebastian, Carle, Reinhold, Schweiggert, Ralf M.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2018
• Subjects: Anthocyanins; Black carrot; Chlorogenic Acid - chemistry; Daucus carota; Heat stability; Intermolecular co-pigmentation; Intramolecular co-pigmentation; Pigmentation; cya-gal; CE; VDT; MW; CP; Intramolecular co-pigmentation; Black carrot; Heat stability; BV; AU; cya-xyl-gal; Intermolecular co-pigmentation; cya-xyl-glc-gal
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2017.07.137

•Cyanidin-3-glycosides showed high intermolecular co-pigmentation at pH 3.6 and 4.6.•At pH 4.6, acylated cyanidins exhibited positive intermolecular co-pigmentation.•Pigment stability was slightly prolonged when adding chlorogenic acid at pH 3.6.•At pH 4.6, chlorogenic acid apparently reduced heat stability of all cyanidins.•Cyanidin-chlorogenic acid interactions were strongly temperature dependent. Spectral characteristics and heat stability (90°C, 5h) of six isolated, structurally related cyanidin-3-O-glycosides from black carrot were investigated in aqueous solutions (pH 3.6 and 4.6) supplemented with chlorogenic acid (molar anthocyanin:co-pigment ratios 1:62.5–1:250). Chlorogenic acid supplementation generally increased absorbance of non-acylated anthocyanins by up to 97.9 and 122.9% at pH 3.6 and 4.6, respectively, being mainly attributed to the formation of intermolecular anthocyanin:co-pigment complexes. The effect significantly decreased when the chain length of the 3-O-linked non-acylated anthocyanins was increased from mono- to di- to triglycosyl moieties, possibly due to steric interferences of bound sugars and co-pigments. Intermolecular co-pigmentation was investigated for the first time for feruloylated and sinapoylated cyanidin-3-O-triglycosides. They exhibited weaker effects (10.8–16.0%) at pH 4.6, and no spectral response was observed at pH 3.6. Chlorogenic acid addition evoked weak enhancement of thermal pigment stability at pH 3.6, while it was highly detrimental for all anthocyanins at pH 4.6.