Effects of pH on the stability of cyanidin and cyanidin 3-O-β-glucopyranoside in aqueous solution

Abstract

The colour variation, colour intensity and stability at various pH values (2.0, 4.0, 7.0 and 9.0) of cyanidin 3-O-β-glucopyranoside (Cy3Glc) and its aglycone cyanidin were investigated during a period of 8 hours storage at 25 °C. Our data showed that pH of aqueous solution had impact on spectroscopic profile of cyanidin and Cy3Glc. Beginning with the most acidic solutions, increasing the pH induce bathochromic shifts of absorbance maximum in the visible range for all examined pH values (with the exception pH 4.0 for cyanidin), while the presence of the 3-glucosidic substitution induce hypsochromic shift. Compared to cyanidin, Cy3Glc has higher colour intensity and higher stability in the whole pH range, except at pH 7.0. The 3-glucosidic substitution influences on the colour intensity of Cy3Glc in the alkaline region. After 8-hour incubation of Cy3Glc and cyanidin at pH 2.0 and 25 °C, 99% of Cy3Glc and only 27% of cyanidin remained unchanged.

Cis–Trans Configuration of Coumaric Acid Acylation Affects the Spectral and Colorimetric Properties of Anthocyanins

“…Methoxylation of the chromophore, compared with hydroxylation, results in slightly redder hues; the h ab values were demonstrated to be negatively correlated with not only the total anthocyanin content of processed blueberry juice but also the delphinidin/malvidin ratio [ 7 ]. Glycosylation of cyanidin at C3 typically intensified and stabilized the color of anthocyanidins in most pH; however, glycosylation of cyanidin at C3 and C5 has been reported to decrease pK h and color stability [ 8 , 9 , 10 , 11 ]. Despite the decreased color stability, this glycosylation pattern also resulted in hue shifts toward purple-blue tones [ 12 , 13 ].…”

A dietary anthocyanin cyanidin-3-O-glucoside binds to PPARs to regulate glucose metabolism and insulin sensitivity in mice

“…Plant food containing C3G that is ingested by humans undergoes digestion in the gut, following which both C3G and its aglycone, cyanidin, can be absorbed by the intestinal epithelium and delivered to the circulation to exert multiple biological functions in tissues 11 . C3G is more stable than its aglycone cyanidin in aqueous solution 12 ; thus, C3G is believed to be the major bioavailable and active form of cyanidin in human tissues.…”

Enrichment of Mango Fruit Leathers with Natal Plum (Carissa macrocarpa) Improves Their Phytochemical Content and Antioxidant Properties

“…Although the concentrations of cyanidin-3-O-β-sambubioside and cyanidin-3-O-glucoside were significantly highest in Natal plum (N1), adding higher amounts of Natal plum (MN2) helped to retain these two compounds at higher levels ( Table 2). The pH of the food matrix and temperature were reported to affect the stability of the cyanidin compounds [29]. Although the variability in the stability of the cyanidin compounds are dependent on the pH of the food matrix and the temperature, cyanidin-3-O-glucoside molecules were reported to be more stable than the cyanidin-3-O-pyranoside molecules [29]; thermal stability of cyanidin-3-O-β-sambubioside was also reported.…”

“…The pH of the food matrix and temperature were reported to affect the stability of the cyanidin compounds [29]. Although the variability in the stability of the cyanidin compounds are dependent on the pH of the food matrix and the temperature, cyanidin-3-O-glucoside molecules were reported to be more stable than the cyanidin-3-O-pyranoside molecules [29]; thermal stability of cyanidin-3-O-β-sambubioside was also reported. However, formation of the quinonoid base and hemiketal (colourless) from the flavylium ion are favoured at higher temperatures [30].…”