Title of Thesis
Determination And Reduction Of Aflatoxin By Gamma
Irradiations In Wheat Maize And Rice
Department Of Chemistry, Faculty Of Sciences /
University Of Agriculture, Faisalabad
|Number of Pages|
|Keywords (Extracted from title, table of contents and
abstract of thesis)|
Composition, Sensitivity, Humidity,
Determination, Linolenic, Rice, Biomass, Maize, Gamma, Irradiations,
Methods, Aflatoxin, Reduction
world-wide are used as staple food. Due to high temperature,
humidity and non-scientific storage prevail the growth of certain
species belong to family Aspergillus. Mycotoxins are small (MW
~700), toxic chemical products formed as secondary metabolites by
fungal species that readily settle on crops and infect them with
toxins in the field or after harvest, during transport and storage.
These compounds cause a potential threat to human and animal health
through the intake of food products prepared from these commodities.
Generally, crops that are stored for more than a few days become a
potential target for mould growth and mycotoxin formation.
Mycotoxins can occur both in temperate and tropical regions of the
world, depending on the species of fungi.The extraction, clean up
and analysis methodology for aflatoxins in cereals (maize, rice and
wheat) were validated and found it efficient and good in respect of
recovery, reproducibility, repeatability, resolution and
cost-effective. The extraction solvent (acetonitrile and water) gave
≥ 85% recovery in spiked cereal samples using MycoSep-226 column.The
sensitivity (LOD) of HPLCFLD was higher as compared to HPLC-UV-Vis
after derivatization of sample extract with trifluoroacetic acid (TFA).
The collected cereals samples from Faisalabad Division, Pakistan
exhibited high level of aflatoxins but after treatment with
γ-irradiation, more than 95% reduction in AFB1 and ≥ 97% in Total
(ΣAFB1, AFB2, AFG1 and AFG2) were observed at a dose of 6 kGy.
Significant affect of radiation was found in wheat samples because
substantial reduction (≥ 95%) was found in AFB1 and total aflatoxins
at high dose of radiation.The level of aflatoxin contamination was
far behind that the recommended limits of EU and FDA, USA. From the
results it is evident that γ- irradiation is a good technology to
remove contaminants like aflatoxins from cereal commodities.
The food quality of irradiated cereals was evaluated to study any
chemical change in protein (amino acids), fatty acid composition and
fungal biomass using different methods.The total biomass (CFU/g)
showed linearity behaviour as increasing the dose level of gamma
irradiation. In some samples of cereals, no microflora (fungi) was
observed after 72 hrs. of incubation.composition revealed that
linolenic acid and oleic acid showed decrease whereas no significant
change was found in other fatty acids. The unsaturated and poly
unsaturated fatty acids remained same after γ-irradiation exposure.
The amino acids profile showed that leucine, lysine, tryptophane and
valine increased while methionine, phenylalanine and threonine
decreased in composition as increased the dose level of exposure of
gamma irradiation.Overall no major difference was observed in any
essential amino acids.The permanent use of contaminated cereals in
the area may pose certain diseases like hepatitis, cancer of liver
or effect of other major organs of the human body.The fatty acid