This invention relates to the elimination of aflatoxin B2, G1 and G2 and reduction of
aflatoxin B1 in defatted rice bran using thermal, shear force and gaseous treatment.
BACKGROUND OF THE INVENTION
Aflatoxins are a class of fungal toxins produced by species of Aspergillus fungi that
sporadically contaminate rice bran during production, harvesting, storage in shelling
or in polishing. Contamination of rice bran with aflatoxins has been recognised since
the 1970s and is a sporadic but re-occur depending upon moisture, heat, and other
growth factors in the field and during storage.
Aflatoxins have been demonstrated to be potent carcinogens that can cause severe
liver diseases(e.g. liver cancer). Defatted rice bran containing these toxins caused
reduction in value of live stock feed and in some cases make it unfit for use as feed.
Food products contaminated with high levels of aflatoxin Bl are unsafe for human
consumption, but they are also unsafe for animal consumption as well. Even animal
products (meat, milk, eggs, etc.) from animals who have consumed aflatoxin B1
contaminated feed are unsafe for human consumption.
A specific type of mycotoxin, aflatoxin B1, is a highly potent contaminant produced
by the fungi Aspergillus flavus and Aspergillus parasiticus during the storage of many
cereal grains and their milled products. Even with the best agricultural practices,
contamination is unavoidable. However, high levels of aflatoxin B1 has been shown
to have carcinogenic, mutagenic, teratogenic, and immunosuppressive effects.
Paddy grain are dehulled to remove the husk that varied between 18-25% depending
upon varieties. Brown rice is separated from hull during shelling operation. Brown
rice is then polished to remove bran (5 to 9%) and obtained milled rice. The bran
obtained is then defatted by solvent (hexane) extraction and then used in the
production of cattle feed. However, during storage and processing the defatted rice
bran got contaminated by the fungi Aspergillus flavus and Aspergillus parasiticus that
produced aflatoxins (B1, B2, G1, G2). Aflatoxins, particularly B1 developed in rice
bran is extremely difficult to reduce to minimum levels 10-15 ug/kg (ppb) set by the
regulatory agency (FSSAI). Known methods for reduction of aflatoxins, particularly
B1 (below safe limit) in defatted rice bran are not commercially effective.
Accordingly, described combination of treatments i.e thermal-shearing-gaseous are
capable of lowering and elimination of the aflatoxins to the permissible limits set for
their acceptance.The treated defatted rice bran be widely used for the consumption of
animals as feed and fodder.
DRAWBACKS IN THE TECHNOLOGIES
In the background of elimination of the aflatoxin B1 ,B2 ,G1 ,G2 process, the
researchers have been used different techniques to meet the prescribed limit of the
end product but these techniques are not commercially viable. These techniques
includes methods of using biotransforming agents to degrade aflatoxin by
microorganisms and the incorporation of microbial enzymes has also been used to
reduce aflatoxin Bl levels, but these methods have not been proven to be
commercially effective and viable.These method require long time since enzymes
incorporated require enough time and specific conditions for the degradation of
aflatoxins.
Other method include the drying under sun and heating in hot air ovens are also not
feasible in handling large quantities of rice bran.The gaseous treatment is also used in
eliminating the aflatoxins but limited to certain point.Hence to overcome the existing
deficiencies extensive experiments have been conducted and thermal-shearinggaseous treatment is finalised.
EFFORTS OR SOLUTION TO DRAWBACKS
The limitations in the methods of the elimination of aflatoxin includes using single
technology which is non-feasible at commercial scale and not able to reduce the
aflatoxin content upto the permissible limits set by the regulatory agency (FSSAI).Use
of the thermal-shearing treatment at particular temperature under specific moisture
content followed by the grinding to reduce particle size and then gaseous treatment
lead the to the elimination of aflatoxin B2, G1 and G2 and reduction of aflatoxin B1
in defatted rice bran lead to meet the permissible limits.
SUMMARY OF THE INVENTION
The invention discloses elimination of Aflatoxin G1, G2 and B2, and reduction of
Aflatoxin B1 to less than 5 ppb, which includes treating the material contaminated by
aflatoxin through the combination of thermal, shearing and gaseous treatment.
It is noted that aflatoxin B1 is generally considered to be the most toxic of the known
aflatoxins.Gaseous and thermal shearing treatment can either completely degrade
mycotoxins or cause chemical modifications, reducing their biological activity. In a
model system gaseous treatment the gas reacts across the 8,9 double bond of the furan
ring of aflatoxin B1 through electrophilic attack, causing the formation of primary
ozonides followed by rearrangement into monozonide derivatives such as aldehydes,
ketones and organic acids.
The invention is easy to operate and has good degradation effect, which is suitable for
degradating aflatoxin in rice bran, controlling aflatoxin content, and has high
application valve and market potential.
This invention relates to the reduction and elimination of aflatoxins present in defatted
rice bran.
DETAILED DESCRIPTION OF INVENTION :
The analysis of commercial bran was carried out using Agilent G6410AA LC/MS
Triple Quadrupole Mass Spectrometer revealed the presence of aflatoxin B1 between
60-144 ppb, aflatoxin B2 between 7-20 ppb, aflatoxin G1 between 0.3-0.7, aflatoxin
G2 between 0.3-0.9 ppb.Therefore, the work was initiated to find commercial viable
method that could reduce these aflatoxin levels below the permissible limits set by
FSSAI(Food Safety Standardisation authority of INDIA).The work consisted of
various treatments given to commercial defatted rice bran large number of trails were
conducted to designed treatments that can reduce the aflatoxins content in defatted
rice bran below the permissible levels.
The preliminary trails carried out showed a reduction in the Aflatoxin B1 and these
experiments are clearly revealed that after the combination of the heat-shearedgaseous treatment the aflatoxin B1 can be reduce to below the permissible limit.
However, the research was carried out to get the minimum levels of aflatoxin. A great
effort was made to reduce the B1 to permissible level of less than 15 ppb (parts per
billion) which will make rice bran fit for animal as well as human consumption.The
combination of treatments led to complete elimination of Aflatoxin G1, G2 and B2,
and reduction of Aflatoxin B1 to less than 5 ppb.
This invention relates to the elimination of aflatoxin B2, G1 and G2 and reduction of
aflatoxin B1 in defatted rice bran using thermal, shear force and gaseous treatment.
1.Thermal-shearing-gaseous treatment led to reduction in aflatoxins in defatted rice
bran.
2 .Thermal-shearing treatment include tempering of defatted rice bran with
appropriate amount of moisture followed by wet thermal and shearing treatment .
3. Thermal-shearing carried out at a particular temperature (150 - 200 *C) at which
the material is subjected to heating and shearing together for a specific period of time.
4. Defatted rice bran is then grounded to a particular particle size to make it suitable
for further treatment.
5. Aflatoxin B1 reduced to 81 % level with thermal-shearing treatment confirmed
from the result obtained from Agilent G6410AA LC/MS Triple Quadrupole Mass
Spectrometer.Results are enclose herewith Annexure No [1] for control sample and
for treated one.
6. The defatted rice bran powder obtained as mentioned in Claim 5 was further given
gaseous treatment under specified temperature and pressure.This treatment lead to
complete elimination of aflatoxin G1, G2 and B2, and caused a reduction of 93%
(3-5ppb) in Aflatoxin B1 determined by Agilent G6410AA LC/MS Triple Quadrupole
Mass Spectrometer.Results are enclose herewith.
7. The treated defatted rice bran powder showed complete elimination of all of the
aflatoxins except B1 and reduction of aflatoxin B1 to less than 5ug/kg (ppb)
confirmed by measuring using Agilent G6410AA LC/MS Triple Quadrupole Mass
Spectrometer.
8. There is complete elimination of all the aflatoxin except aflatoxin B1 its
concentration decreased from 80-100 ppb(parts per billion) to 3-8 ppb (parts per
billion) verified by Agilent G6410AA LC/MS Triple Quadrupole Mass Spectrometer.
The defatted rice bran with reduced level of aflatoxin B1 was under the minimum
limit set by FSSAI for cereals and cereal based products for human consumption.
However, this combination of treatment will also allow the safe use of defatted rice
bran for livestock feed.
Thermal-shearing treatment
Extrusion is a high-temperature-short-time physical treatment during which materials
are subjected to high temperatures and mechanical shearing at relatively low levels of
moisture content lead to reduction in microbial load, enzyme (in) activation, color
changes. Extrusion is a cost effective process as it achieves high productivity in a
single processing step by cooling and forming the product. An extruder can handle at
wide variety of raw ingredients and processing conditions which proves its versatility
and consequently broadens its applicability to food products.
Deoiled rice bran was subjected to extrusion in a laboratory-scale twin-screw extruder
(Clextral, BC 21, Firminy, France) with three individual barrel sections, each with
separate temperature control. The terminal section of the extruder was heated by an
induction heating belt and the feeding section of barrel was cooled with running
water. The temperature of these three barrels was set at 50°C (feed section), 80°C, and
120~200°C, respectively. The rice bran blends were extruded at four different die-exit
temperatures: 120, 160, 180, and 200°C. The diameter of the screw was 75 mm, and
the length-to-diameter ratio was 28 : 1. The screw elements included kneading blocks
and reverse screw elements. Screw speed was operated at 600 rpm. The die was
designed with two circular holes at 5 mm diameter.
The moisture content of rice bran was adjusted 15-20% specified for the extruder.
Moisturised raw material was introduced to the extruder at a rate of 0.2 kg/min. When
stable extrusion conditions were reached, the extrudates formed were carefully
collected, air cooled and tightly sealed in PET jars. The obtained extrudes of rice bran
were ground to pass a 0.2 mm screen and then oven-dried at 50°C to reach a final
moisture content of 5.1% (w/w).
Gaseous Treatment
Ground extruded rice bran was further treated by contacted with ozone in a covered
vessel at atmospheric pressure. Aflatoxin removal was significantly greater at 200 °C
than at 150 °C. Gaseous treatment can cause chemical modifications, reducing their
biological activity. In a model system, Gas reacts across the 8,9 double bond of the
furan ring Alflatoxin B1 through electrophilic attack, causing the formation of
primary ozonides followed by rearrangement into monozonide derivatives such as
aldehydes, ketones and organic acids.
Using ozone treatment to degrade aflatoxin Bl in defatted rice bran may have several
benefits. For example, ozone may be produced on-site, eliminating the cost and risk
associated with transporting and storing a potentially dangerous compound. this gas is
highly reactive and self- decomposes into oxygen, eliminating the need to store and
dispose of harmful chemicals. Further, used gas is non-residual, meaning that when
used to treat food products, it does not leave behind residue like many pesticides and
other chemicals currently in use to treat food products.
Method of reducing aflatoxin Bl in Defatted rice bran content is exposed to the
Thermal shearing and gaseous -rich environment for 3-15 hr.This reaction takes place
in a sealed reaction vessel for 12 -15 hours or less.
The treatments is easy to operate and has good degradation effect, which is suitable
for degradation of aflatoxin in rice bran, peanut powder , peanut kernel, peanut oil,
cotton seed crop, and controlling aflatoxin content, and has high application valve and
market potential.
There is complete elimination of all the aflatoxin except aflatoxin B1 its concentration
decreased from 80-100 ppb(parts per billion) to 3-8 ppb (parts per billion) verified by
Agilent G6410AA LC/MS Triple Quadrupole Mass Spectrometer.
The defatted rice bran with reduced level of aflatoxin B1 was under the minimum
limit set by FSSAI for cereals and cereal based products for human
consumption.Report of LCMS for the control and the treated rice bran is hear by
enclosed.

CLAIMS
We/I claim
1. A method for reduction of aflatoxins from defatted cereals, oil seeds and
feedstuffs contaminated therewith comprising subjecting said defatted cereals,
oil seeds and feedstuffs to combination of thermal, shear force and gaseous
treatment for making it suitable as livestock feed.
2. A method for reduction of aflatoxins as claimed in Claim 1, wherein defatted
rice bran is grounded to a particle size of (0.19-0.25mm) to make it suitable for
further treatments
3. A method for reduction of aflatoxins as claimed in Claim 1, wherein thermalshearing treatment include tempering of defatted rice bran with (15-20%) of
moisture followed by wet thermal and shearing treatment
4. A method for reduction of aflatoxins as claimed in Claim 1, wherein Thermalshearing was simultaneously carried out at a temperature of between 100-200*C
for 30 sec -180 sec to obtain treated defatted rice bran powder with reduction of
80-83% of Aflatoxin B1 from 50-80 ug/kg (ppb) to 12-13 ug/kg (ppb).
5. A method for reduction of aflatoxins as claimed in Claim 1, wherein the
treated defatted rice bran powder obtained in claim 4 is further subjected to
gaseous treatment at 25-30*C temperature and pressure not more than 2-3 psi
resulting in complete elimination of aflatoxin G1,G2 and B2, and reduction of
93% (3-5ppb) of Aflatoxin B1.