Biological detoxification of Monascus purpureus pigments by heat-treated Saccharomyces cerevisiae.

Today, there is an increasing concern about the consumption of synthetic colorants in food because of their possible health hazards. Monascus purpureus has attracted a great deal of attention as it produces various coloured pigments with high chemical stability, but it also produces citrinin, a secondary toxic metabolite, along with the pigments. This study aims to investigate the amount of pigment and citrinin reduction by different treatments with Saccharomyces cerevisiae such as heat treatment and suspension concentration. The results indicated that the ability of S. cerevisiae regarding citrinin adsorption increased with increase of temperature and yeast concentration. The maximum extent of citrinin adsorption was related to heat treatment at 121 °C and a yeast concentration of 105 cells mL-1 , for which citrinin reduced from 4.43 mg L-1 in control to 0.1 mg L-1 . Heat treatment of 103 cells mL-1 suspension of S. cerevisiae cells at 50 °C, with 0.56 mg L-1 citrinin remaining in the medium, showed the lowest ability for citrinin binding. The optimum absorbance of all red, orange and yellow pigments was observed for the heat treatment at 50 °C and yeast concentrations of 103 and 104 cells mL-1 which was greater than that for the control. We can conclude from this study that heat treatment with S. cerevisiae can be a useful way to reduce citrinin to below the standard limits. © 2019 Society of Chemical Industry.