Studies on the Degradation of Natural Pigments

Part 1. Photodegradation of lycopene and β-carotene

Abstract

Effects of monochromatic lights on the photolysis of lycopene or β-carotene were studied.
(1) The degradation of the pigments dissolved in n-hexane was significantly enhanced by the irradiation with ultraviolet lights of wave length 225-350nm, while in the visible region it was hardly discernible. β-Carotene was several times as stable as lycopene. (2) The fine crystal of lycopene exposed to ultraviolet lights was led to the considerable deterioration of the color, and the visible lights in the wave-length region under 500nm also gave rise to the some extent of the degradation. The lycopene held by adsorption on the filter paper was much more labile compared to the pigment suspended in water.