Evidence of new pigments resulting from reaction between anthocyanins and yeast metabolites

Four groups of orange pigments have been synthesized from mono-glucosylated anthocyanins and either ethanal, α-ketoglutaric acid, acetone or 3-hydroxybutan-2-one. They were formed by ring - formation involving the C-5 hydroxyl group and the C-4 of the anthocyanin, and the enolic double bond of the four other compounds cited above, followed by a dehydration and an oxidation step. The pigments obtained were purified by low pressure chromatography, followed by analysis by HPLC coupled to both a diode-array detector, and an electrospray mass-spectrometer. Some of the four pigments have been detected in synthetic media containing extracts of grape anthocyanins, after fermentation.