Abstract—The ability of Monascus species to produce many different types of pigments and secondary metabolites, such as monacolin K and citrinin, is remarkable. Mutations of Thai strains of Monascus purpureus in TISTR 3002 were induced by using an ultrasonic wave of 45 kHz for 2 min at 28^oC. The mutations were carried out for 4 generations in order to develop efficient food colorants and to study the enhancement of secondary metabolites. The results showed that monacolin K could not be detected in fermented broths from any of the 4 generations. Mutant generations from TISTR3002, contained citrinin at concentrations in G0 (wild type), G₁, G₂, G₃ and G₄ of 18.48, 0.01, 64.98, 2.34 and 110.96 μg/ml, respectively. A quantitative analysis of pigments was performed on all generations and results indicated that the stability of derivatives of yellow, orange and red pigments was greatest at pH 8. A significant increase in pigment stability was gained when TISTR 3002 was ultrasonically induced up to G4. Pigment derivatives of all generations of TISTR 3002 exhibited a greater stability in the basic pH range when compared with an acidic pH range.

Index Terms—Monascus purpureus, yellow pigment, orange pigment, red pigment, mutant, ultrasound

Cite: Issara Wongjewboot, Sasithorn Kongruang, "pH Stability of Ultrasonic Thai Isolated Monascus Purpureus Pigments," International Journal of Bioscience, Biochemistry and Bioinformatics vol. 1, no. 1, pp. 79-83, 2011.