Anthocyanins


 * Basic structure [[File:anthokyan.jpg]]


 * Pelargonidin Pg... R1 = H, R2 = H violet-red
 * Cyanidin Cy... R1 = H, R2 = OH purple
 * Delfinidin Dp... R1 = OH, R2 = OH blue-violet
 * Peonidin Pn... R1 = H, R2 = OCH3 violet
 * Petunidin Pt... R1 = OH, R2 = OCH3 dark red
 * Malvidin Mv... R1 = OCH3, R2 = OCH3 blue-violet


 * Carbohydrates: Glu, Gal, Xyl, Ara, Rha, always C-3, often C-3 and C-5, rarely C-7
 * Acids: p-coumaric, caffeic, ferulic

Examples: Anthocyanins of fruits and vegetables
 * Cyanidin-3-O-β-D-glucoside (generally known) [[File:influence-ph-on-anthocyanins.jpg]]
 * (E)-petunidin-3-O-[6-O-(4-O-p-kumaroyl-α-L-rhamnopyranosyl)-β-D-glukopyranosid]-5-O-β-D-glukopyranosid [[File:petanin.jpg]]
 * Trivially: petanin (red potato variety)


 * Dependence of coloration on various factors:
 * pH of the environment;
 * Copigmentation, or transformation to other dyes;
 * sulphur dioxide;
 * hydrogen peroxide

pH of the medium
 * [[File:vliv-ph-na-antokyany.jpg]]


 * Copigmentation
 * Interaction with procyanidins (e.g. catechins, so-called copigments) → colour complex.
 * Transformation to other dyes, colour complex → dimer (oligomer), insoluble condensation products, sediments phlobaphenes. [[File:flobafeny.jpg]]


 * Sulphur dioxide → colourless sulphonic acids. [[File:vliv-ph-na-antokyany.jpg]]
 * Hydrogen peroxide → colourless products. [[File:vliv-ph-na-antokyany.jpg]]

Internal links

 * Colored substances from wikiskripta (1. LF UK, NT)