Biopigments from Monascus: strains selection, citrinin production and color stability

Abstract

Fungi form the genus Monascus are a promising source for natural color additives. However, before effectively applying Monascus to foods, it is important to select strains which produce large amounts of biopigments but little or no citrinin, a mycotoxin usually also produced by these fungi. Also, color stability of these pigments should be properly investigated. In order to compare Monascus strains for biopigment production in solid substrate fermentation (SSF), 4 strains (NRRL 1991, NRRL 2897, CCT 3802 and LPB 31) were cultivated over PDA in Petri dishes, and compared for radial growth velocity. Also, these strains were cultivated over cooked rice, and compared in relation to their capacity to produce biopigments and citrinin. The results showed that the strain LPB 31 is the best strain for biopigment production in SSF, giving both higher pigment concentration and lower citrinin concentration on the extracts, showing that it is a promising strain for production of this bioproduct. Biopigmentassays for heat and pH stability, show that these biopigments are unstable at low pH and high temperatures, but may be successfully used at near-neutrality pH's and in non-thermal processed foods.