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High-performance liquid chromatography of some anthocyanidins and flavonoids

An interchange experiment showed that it was the gluten/starch fraction of flour and not the level of ferulic acid that controlled rapid breakdown of overmixed doughs. This finding also explains why a large amount of exogenous ferulic acid is needed to cause rapid breakdown. Quantitative analysis of the phenolic acids in wheat flour and doughs showed ferulic acid to be the predominant phenolic acid. During overmixing of wheat flour doughs, ferulic acid was lost from those fractions that initiated breakdown in gluten/starch doughs. As wheat flour dough was overmixed, the concentration of ferulic acid in the free form decreased from 1·0 to 0·3 mg/kg and in the soluble, bound form from 3·8 to 0·9 mg/kg. Ferulic acid in the insoluble, bound form did not decrease in concentration, remaining at about 36 mg/kg. These data are in agreement with the theory that ferulic acid in the water-soluble fraction of wheat flour interacts with the gluten/starch fraction to bring about rapid dough breakdown.

The separation of some anthocyanidins, anthocyanins, proanthocyanidins and related substances by means of reversed-phase high-performance liquid chromatography is described. The system consists of a LiChrosorb RP-18 (10 μm) Knauer column and a combination of isocratic and linear gradient elution (solvent A: water—formic acid (95:5 v/v); solvent B: methanol; 35°C). These results and those of previous studies on related compounds are employed to present a “review chromatogram” demonstrating the separatory power of the RP—HPLC technique. The possible use of this system for the analysis of complex mixtures of natural products is discussed.