Characterization of anthocyanins in fruit juices and natural colorants

Graduation date: 1988A method for separation and characterization of individual anthocyanins was\ud developed. High Performance Liquid Chromatography (HPLC) with a polymer based\ud reversed-phase column was used to separate the pigments while on-line Photodiode\ud Array Detection (PDA) was employed to record the UV and Visible spectrum of the\ud individual peaks. Spectral information obtained from on-line PDA detection provided\ud information about: 1) the nature of the aglycone, 2) the sugar substitution pattern\ud and 3) the presence or absence of hydroxy aromatic organic acids. The nature of the\ud glycosidation can be determined from the HPLC retention characteristics.\ud The HPLC/PDA methods were employed to characterize the anthocyanin\ud profiles of the pigments in cranberry, roselle, cherry, bilberry, grape, red cabbage,\ud black raspberry, blackberry, elderberry, plum, blackcurrant and strawberry. The\ud anthocyanidin profiles were also determined for the samples for purposes of\ud confirmation of the anthocyanin data.\ud In addition to the anthocyanin and anthocyanidin profiles, the general coloring\ud properties for most of the samples were also determined. Included were Hunter L, a, b values, total anthocyanin pigment concentration, wavelength maxima, percent\ud tannin measurements, tinctoral strength, pH measurements and titratable acidity