Ultraviolet spectra Carotenoids

Shoulders or peaks were observed at 465, 443 and 425 nm of the visible spectrum (due mainly to the carotenoids present) and 325, 280 and 245 nm of the ultraviolet spectrum (due mainly to polyphenols, flavonoids and ascorbic acid, respectively). Absorbance of the maxima peaks obeyed Beer s law while the 443 325 nm absorbance ratios remained essentially constant. When fruit extractor pressures were increased, the UV absorbance of the resulting juice increased and the 443 325 nm absorbance ratio decreased. Spectra of alcoholic solutions of the rag and albedo components... 

The mixture was next quenched with water and the resulting precipitated oil taken up in pentane, dried with sodium sulfate, and distilled under vacuum. The product was collected at 100° to 110°C at 0.001 mm/Hg, nD24-5 1.50 60. The infrared and ultraviolet spectrum corresponded to 10,ll-didehydro-9-ethoxy-9,12-dihydroretinol acetate, using carotenoid nomenclature based on the parent compound retinol. 

FIGURE 6.4 General ultraviolet (UV)-visible light absorption spectrum of carotenoids. 

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