Two new monascus red pigments produced by Shandong Zhonghui Food Company in China

摘要

Different monascus red pigments were produced by many companies in China with their own strains, but most of them are rarely identified. Two new monascus red pigments of the homologous series were isolated from commercial monascus red pigments produced by Shandong Zhonghui Food Company in China, and their structures were identified by visible light absorbance, Fourier transform infrared, Nuclear magnetic resonance, Electrospray ionization-mass spectrometry and X-ray diffraction. Their molecular weights were 303.5 and 331.5, respectively. Their molecular formulas were C18H25NO3 and C20H29NO3. Their lambda (max) are observed at 426.0, 493.5 nm. They are characterized by the absence of lactone ring, carbonyls and methyl, the presence of hydroxyls and the existence of double bonds at the end of the aliphatic side chains. The characteristic X-ray diffraction pattern of the new monascus red pigments is the strong diffraction peaks at 31.62A degrees, 45.34A degrees and 56.40A degrees 2 theta and the weak ones at 27.28A degrees, 66.08A degrees and 75.20A degrees 2 theta. The findings in the paper have inferred that many monascus red pigments might be synthesized in the half way of well-known red pigments synthesis. Those two pigments have potential application in beverages.