Assessment of the dyeing properties of pigments from Monascus purpureus

Monascus purpureus C322 was cultivated on well-established production media to yield prevailingly red or orange pigment-rich ethanolic extracts. Once these extracts had been diluted by an overall factor of 50, they were used as such to dye raw wool standard specimens differently premordanted using alum or stannic chloride. Independently of the mordant used, the specimens dyed with the red pigment-rich extracts showed a pale red colour tending to pink, whereas the specimens dyed with the orange pigment-rich extracts exhibited a more definite orange colour. By carrying out a few colourfastness standard tests (manual washing at 40 ◦C, acid and basic perspiration and hot pressing), stannic chloridepremordanted wool specimens dyed with the red pigment-rich extracts were found to be less resistant to acid and basic perspiration than their orange counterparts. Since the production of the orange pigmentrich ethanolic extracts appeared to be more cost-effective than that of their red counterparts, the former might support the present demand for colorants of natural origin in the textile sector.  2005 Society of Chemical Industry