52
dete rioration. M. purpureus is the most commonly used strain in red rice production. The mycelium of this strain is white in early stages. In due course of time, the
mycelium changes to a rich pink colour and then to a distinctive orange yellow
colour, thereby indicating the increased acidity of the medium. As the culture ages,
a deep crimson colour is formed (INPR 2006).
Certain other strains of Monascus spp. are capable of producing mycotoxin citrinin. During fermentation, the levels of citrinin can be regulated to safe levels by the
use of non-toxic strains and by optimizing culture conditions. However, uncontrolled starter cultures are used in many industrial operations while carrying out
fermentation (Nout and Aidoo 2010).
4.4.3.2 Manufacturing Process
Since the texture of the product is solid, the method followed for its manufacturing
is solid-substrate fermentation. Lucas et al. (1993) reported a swing bioreactor that
provided mild agitation. The biggest advantage of using controlled reactors is that
the environmental conditions can be controlled easily. Several optimum conditions
for angkak production include 34% moisture content of the substrate and a fermentation period of 7 days at 28.8 °C.
First of all, the polished rice is soaked overnight in water, steamed and allowed
to cool down. Then inoculation is carried out with the spores of Monascus spp.
Incubation of about 1 to 2 weeks during solid-substrate fermentation allows the
mould to grow and produce its secondary metabolites. Some of the major pigments
produced include the purple pigment rubropunctamin, orange pigments rubropunctatin and monascorubrin and the yellow pigments monascin and ankaflavin (Pastrana
et al. 1995). The schematic representation of angkak production has been shown in
Fig. 4.3. These pigments are heat-stable and also capable of surviving in a wide
range of pH. The nature and the quantity of pigment produced are purely dependent
on the type of strain being used and the environmental conditions being produced
for production (Miyake et al. 2008).
Several other cereals apart from rice are used as substrate for angkak production
such as corn, but the high-quality product can only be achieved by optimizing the
culture conditions. One such research suggested that addition of lactose and yeast
extract in fermentation media resulted in high levels of pigment production
(Pattanagul et al. 2007). According to Lee et al. (1995), solid-liquid fed-batch cultures gave a comparatively higher pigment yield. Different strains of Monascus,
types of substrate, incubation temperature, pH and moisture content are some of the
important factors indicating different production of their metabolites in angkak
(Pattanagul et al. 2007).
R. Kumari et al.
dete rioration. M. purpureus is the most commonly used strain in red rice production. The mycelium of this strain is white in early stages. In due course of time, the
mycelium changes to a rich pink colour and then to a distinctive orange yellow
colour, thereby indicating the increased acidity of the medium. As the culture ages,
a deep crimson colour is formed (INPR 2006).
Certain other strains of Monascus spp. are capable of producing mycotoxin citrinin. During fermentation, the levels of citrinin can be regulated to safe levels by the
use of non-toxic strains and by optimizing culture conditions. However, uncontrolled starter cultures are used in many industrial operations while carrying out
fermentation (Nout and Aidoo 2010).
4.4.3.2 Manufacturing Process
Since the texture of the product is solid, the method followed for its manufacturing
is solid-substrate fermentation. Lucas et al. (1993) reported a swing bioreactor that
provided mild agitation. The biggest advantage of using controlled reactors is that
the environmental conditions can be controlled easily. Several optimum conditions
for angkak production include 34% moisture content of the substrate and a fermentation period of 7 days at 28.8 °C.
First of all, the polished rice is soaked overnight in water, steamed and allowed
to cool down. Then inoculation is carried out with the spores of Monascus spp.
Incubation of about 1 to 2 weeks during solid-substrate fermentation allows the
mould to grow and produce its secondary metabolites. Some of the major pigments
produced include the purple pigment rubropunctamin, orange pigments rubropunctatin and monascorubrin and the yellow pigments monascin and ankaflavin (Pastrana
et al. 1995). The schematic representation of angkak production has been shown in
Fig. 4.3. These pigments are heat-stable and also capable of surviving in a wide
range of pH. The nature and the quantity of pigment produced are purely dependent
on the type of strain being used and the environmental conditions being produced
for production (Miyake et al. 2008).
Several other cereals apart from rice are used as substrate for angkak production
such as corn, but the high-quality product can only be achieved by optimizing the
culture conditions. One such research suggested that addition of lactose and yeast
extract in fermentation media resulted in high levels of pigment production
(Pattanagul et al. 2007). According to Lee et al. (1995), solid-liquid fed-batch cultures gave a comparatively higher pigment yield. Different strains of Monascus,
types of substrate, incubation temperature, pH and moisture content are some of the
important factors indicating different production of their metabolites in angkak
(Pattanagul et al. 2007).
R. Kumari et al.