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.<br>Fungos do gênero Monascus são uma fonte promissora de corantes vermelhos naturais. No entanto, antes de se aplicar Monascus a alimentos, é importante selecionar linhagens capazes de produzir grandes quantidades de pigmentos, com o mínimo possível de citrinina. Além disso, a estabilidade de cor desses pigmentos deve ser adequadamente investigada. Com o objetivo de comparar linhagens de Monascus para a produção de biopigmentos em fermentação em substrato sólido (FSS), 4 linhagens (NRRL 1991, NRRL 2897, CCT 3802 e LPB 31) foram cultivadas sobre PDA em placas de Petri, e comparadas com relação à velocidade de crescimento radial. Além disso, essas linhagens foram cultivadas em arroz cozido, e comparadas quanto à sua capacidade de produção de biopigmentos e de citrinina. Os resultados mostram que a linhagem LPB 31 é a melhor linhagem para produção de biopigmentos em FSS, dando tanto maior concentração de pigmentos quanto menor concentração de citrinina, mostrando que se trata de uma linhagem promissora para a obtenção deste bioproduto. Os biopigmentos extraídos dos substratos fermentados foram testados quanto à estabilidade frente ao calor e ao pH, mostrando que os biopigmentos de Monascus são instáveis em pH's baixos e altas temperaturas, mas que podem ser usados sem problema em condições de neutralidade, em alimentos sem processamento térmico

Optimization of Monascus Pigment Production and its Antibacterial Activity

“…It was found that maximum absorbance at 510 nm (red pigment) was obtained around 25 to 32°C, while beyond 40°C; there was a drastic reduction in the amount of red pigment. It was reported that there is shift in absorbance maxima of the pigment extract at different incubation temperatures (Carvalho et al, 2005). Reports also revealed that the optimum cultural conditions for Monascus purpureus pigment production is 3 days of incubation period at 32°C, and pH 6.0 (Lin et al, 2008).…”

“…The Monascus red pigment production by submerged fermentation as well as solid-state fermentation is widely studied (Hajjaj et al, 2000a;Carvalho et al, 2005). Monascus pigmented rice also known as angkak or red mould rice is known for its beneficial effects for several centuries (Hesseltine, 1965).…”

Monascus spp.: A source of Natural Microbial Color through Fungal Biofermentation

“…However, spurred by renewed interest in natural remedies, recent biochemical and pharmacological studies have identified red fermented rice as a beneficial dietary supplement for maintaining a healthy balance of cholesterol and related lipids in the body [35]. The genus Monascus produces the most famous secondary metabolites which have been purified and identified, including monacolins that are responsible for reducing cholesterol levels in blood [33,36,37]. γ-Aminobutyric acid (GABA), dimerumic acid with medical effects and citrinin as an antibacterial agent have also been identified as secondary metabolites [34,36,[38][39][40].…”

Production of food colourants by filamentous fungi

“…They are produced both in complex and chemically defined media (Hajjaj et al, 1997;Mossini and Kemmelmeier, 2008). Citrinni production is inherent in some strains and there is no relationship between pigment and citrinin synthesis (Pisareva et al, 2004;Carvalho et al, 2005).…”

“…can be controlled by optimizing the fermentation conditions such as media components, aeration, pH and temperature (Hajjaj et al, 1999, Zhang et al, 2013, or screening for citrinin-free strains, and through genetic regulation (Carvalho et al, 2005;Chen and Hu, 2005;Jia et al, 2010;Feng et al, 2014;Kang et al, 2014;. Abou-Zeid (2012) reported that aqueous extracts obtained from Neem (Azadirachta indica A. Juss) and other medicinal plants were able to reduce growth and citrinin production by Penicillium citrinum under in vitro conditions in liquid media.…”