Abstract
The color properties and stability of three types of 3-deoxyvitisins derived from peonidin (deoxyvitisin A, B and methyldeoxyvitisin) were studied using UV-Visible spectroscopy. Similarly to pyranoanthocyanins, the conjugated double bonds among pyranic rings C and D provide a higher electronic delocalization that prevents the nucleophilic attack of water at position 2 and the subsequent formation of the hemiketal and chalcone species. Consequently, besides the flavylium cation (AH(+)), neutral (A) and ionized bases (A(n-)) have been identified by increasing pH, and the respective acidity constants were determined. The acidity constant values for the formation of the neutral quinoidal base (pK(a2(deoxyvit A)) = 4.8, pK(a1(deoxyvit B)) = 4.7 and pK(a1(methyldeoxyvitisin)) = 5.2) are slightly higher than the ones reported in the literature for their corresponding 3-glucosyl derivatives (vitisins). Given their higher stability, these pigments may be regarded as potential food colorants.
Original language | English |
---|---|
Pages (from-to) | 539-544 |
Number of pages | 6 |
Journal | New Journal of Chemistry |
Volume | 38 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2014 |
Keywords
- ANTHOCYANIN-DERIVED PIGMENTS
- RED WINES
- EQUILIBRIUM FORMS
- FLAVYLIUM SALTS
- VITISIN-B
- DEOXYANTHOCYANIDINS
- ACID
- DYE