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Physical and Chemical Factors Affecting the Stability of Monascus Pigments and Photocatalytic Degradability of Citrinin

ZHANG Xiao-wei1,2,WANG Chang-lu1,*,CHEN Mian-hua1,WANG Yu-rong1   

  1. 1. Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology,
    Tianjin University of Science and Technology, Tianjin 300457, China;2. College of Food Science and Engineering,
    Xuchang University, Xuchang 461000, China
  • Online:2013-08-15 Published:2013-09-03
  • Contact: WANG Chang-lu

Abstract:

The effects of different ethanol concentrations, temperature, light exposure and pH on the stability of
Monascus red pigments were studied by means of UV-visible spectroscopy. Under the conditions of 80% aqueous
ethanol solution, below 70 ℃, pH 5-7 and darkness, the stability of Monascus red pigments was the best. In ethanol
solutions, the pigments were seriously affected by strong acids (pH 2), strong alkalis (pH 9-11) and high temperatures
(80-100 ℃). Different light sources exerted diverse effects on these pigments. Sunlight caused the most serious
damage to them, whereas their stability showed no apparent differences when exposed to UV light or blue light or in
darkness. Meanwhile, the effects of sunlight, incandescent light, blue light and UV light on the stability of citrinin
standard and extract from Monascus red pigments were analyzed by HPLC. After 5 min of UV illumination, 56% and
71% of the initial amount of citrinin remained in the two samples, respectively, indicating that citrinin can be degraded
under short-time UV illumination.

Key words: Monascus pigments, physical and chemical conditions, photocatalytic degradability, citrinin

CLC Number: