Citrinin and color analysis of angkak collected from several regions in Indonesia

Angkak, a fermentation product of rice by Monascus sp., is used for natural food coloring, spices, and medicine by Indonesian people who believe in its pharmacological properties. However, Monascus sp. also produces a secondary metabolite, hepato-nephrotoxic mycotoxin citrinin. The biosynthesis of pigments and citrinin is generated from a tetraketide point in the polyketides pathway. This study aims to detect the levels of citrinin and examine its relationship with the color of angkak in Indonesia. Thirty samples were collected from eight different sites in Indonesia. ELISA method was used to detect the citrinin content. Meanwhile, the color analysis was based on the CIE L*a*b* system and the measurement of its pigments was conducted using spectrophotometer UV-vis. All samples were grown on PDA (Potato Dextrose Agar) media. Mold contamination was found, ranging from 1.67% to 85.33%. The results of citrinin content measurement of the angkak ranged from 17.94 ppm to 142.74 ppm. The color measurement showed that the angkak color was various, from bright red (L* 44.78, a* 21.54, b* 8.67) to very dark red (L* 35.62, a* 17.32, b* 5.43). The ethanol-soluble yellow (OD400) and red (OD500) pigment contents were in the ranges of 83.80 AU/g to 306.52 AU/g and 100.86 AU/g to 318.18 AU/g, respectively. However, based on the Pearson correlation analysis, there was no correlation between the citrinin content and the color value of angkak.