Abstract:

Effects of illumination intensity (which was determined by quantifying the light absorbed using a luxmeter),
wavelength and irradiation time on the preservation rate of Monascus pigments were examined. Sunlight (2 800–31 000 lx)
caused the most serious photodegradation for monascus pigments whereas indoor natural light (54–2 050 lx) had relatively
less serious effects, and no photodegradation was observed under dark condition (0 lx) The preservation rate of Monascus
pigments was decreased with increasing illumination intensity and irradiation time. Under the condition of the same illumination
intensity but different wavelengths, the preservation rate of Monascus pigments followed the decreasing order: red light > yellow
light > green light > blue light > purple light. Monascus pigments were more sensitive to ultraviolet-C light. Under the same
condition, water-soluble Monascus pigments were more stable than alcohol-soluble Monascus pigments.

Key words: Monascus pigments, photostability, illumination intensity, preservation rate