The Effect of Different Strains of Monascus purpureus on the Color Value and Citrinin in Angkak and Their Similarities using ctnA Gene

Abstract

The present study was conducted to evaluate the color value, pigment, and citrinin content from red yeast rice produced by six different strains of Monascus purpureus. The difference of the six strains is based on the phenotypic properties of cultures in Malt Extract Agar (MEA) media. Further, the degree of similarity among the tested citrinin-producing strains was analyzed by using DNA sequence from ctnA gene.   The color value was analyzed based on CIE system, including lightness (L*), redness (a*), and yellowness (b*), whereas the pigment was analyzed by extracting angkak with 75% ethanol and determined spectrophotometrically using UV-Vis to obtain absorbance value (OD). Citrinin was analyzed by using ELISA method. The tested Monascus purpureus strains significantly affected the color value, pigment, and citrinin in angkak. All the isolates yielded various concentration of citrinin ranging from 0.24 ppm to 146.71 ppm. The resulting phylogeny supported the placement of six strains as a single clade with Monascus ruber M7/KT781075.1, M. aurantiacus EU309474.1, and M. purpureus orf1/AB243667.