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Fig. 1. Illustration of the mathematical integrations of the fluorescence spectra for milled rice (having no carotene) and milled rice spotted with ß-carotene. The addition of ß-carotene (B) causes a shift downward (arrow) of the spectral envelope at the lower wavelengths since carotenoids, in general, absorb light of wavelengths less than about 525 nm. In the presence of carotenoids, the area above the baseline curve (dark shading in A and B) becomes greater. Changes in the curves of the spectral envelope are measured in comparison to the straight line of the corresponding baseline spectrum by subtracting the area under the baseline from the area under the spectral evelope, thus producing the net integrated fluorescence intensity.
