الفهرس 
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Abstract
Aflatoxins (AFs) are fungal unavoidable contaminants that occur naturally in a large variety of food commodities. They are highly carcinogenic, mycotoxins produced primarily by the fungus Aspergillus flavus and Aspergillus parasiticus. AFs contamination is a worldwide problem, especially in warmer climates, and the toxin can enter the food chain through the eating of cereals, and their products and can occur during all stages of growth, harvest, storage.
AFs contamination of agricultural crops causes annual losses of more than $750 million in Africa. In developing countries, many individuals are not only malnourished but are also chronically exposed to high levels of Aflatoxins in their diet.
Aflatoxin B1 is not only a big problem at crops production level, but also it has become a global health issue because of the consequences that the consumption of this toxin generates in animals and human beings. According to our research results all tested samples contain aflatoxin B1 which exceeds the legal limit by several folds. Efforts to reduce aflatoxin exposure require the commitment of sufficient resources and the collaboration between the agriculture and public health communities as well as local regional, national, and international governments. It is also important to increase disease surveillance, food monitoring, laboratory detection of mycotoxins and public health response capacity in Egypt in order to reduce cancers and decrease the mortality rates in human and animals.
Aflatoxin B1 is the most toxic and it is known for its harmful effects on humans and animals and is classified by the International Agency of Research on Cancer (IARC) as group I carcinogen meaning that it is a proven cancer-inducing agent, so, it is currently regulated by the Food and Drug Administration (FDA).
Physical, chemical, and biological methods of mycotoxin decontamination are reported. Each of these methods has its own advantages and disadvantages, depending on the reduction in the nutrition value and the possibility of the introduction of new toxic or carcinogenic-mutagenic substances.
The aim of this work is to compare between two procedures for Aflatoxin B1 decontamination in maize and wheat using Gamma irradiation and ozone treatment and the impact on nutritive values with comparison with previous results obtained with other Gamma radiation doses.
A total of 60 cereal samples of maize (30 samples) and wheat (30 samples) were collected from the local market in Alexandria Governorate, during 2017. The bulk sample unit of each cereal type (1250 gram) was divided into 5-sub-groups, each of 250 gram, served as follows: SG1(control group), SG2 (exposed to 7 KGy, gamma-rays), SG3 (exposed to 10 KGy, gamma-rays), SG4 (exposed to 70 ppm ozone gas for one hour), and SG5 (exposed to 100 ppm ozone gas for one hour).
Each sample was subjected to the following:-
A. Aflatoxin B1 determination, using HPLC.
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B. Proximate analysis including; (ash, moisture, fat, protein, crude fibers, calculation of carbohydrates and calories).
C. Fatty acid profiles analyses by GC.
D. B-complex vitamin analyses including thiamine B1, riboflavin B2, and folic acid B9.
A. With respect to aflatoxin B1:
Before treatments the mean levels for the toxin was 78.03 ± 20.99 for maize and 47.76 ± 11.45 for wheat which are too much higher than the legal limit according to FAO (10 ppb for maize and 5 ppb for wheat).
For maize the level of the toxin (ppb) decreased to (40.52 ± 12.99, 14.34 ± 5.54, 27.99 ± 9.14 and 7.70 ± 3.44) at (7 KGy, 10 KGy, 70 ppm for one hour and 100 ppm for one hour) respectively these means that the aflatoxin B1 was reduced by (48.07%, 81.62%, 64.13% and 90.13%) respectively to be within the legal limit in case of ozone at 100 ppm.
For wheat the level of the toxin (ppb) decreased to (23.55 ± 6.52, 7.79 ± 2.31, 14.14 ± 3.31 and 3.72 ± 2.07) at (7 KGy, 10 KGy, 70 ppm for one hour and 100 ppm for one hour) respectively these means that the aflatoxin B1 was reduced by (50.69%, 83.68%, 70.39% and 92.21%) respectively to be within the legal limit in case of ozone at 100 ppm.
Storage with treatments:
Gamma radiation
Gamma radiation and ozone gas help in extending the self-life of cereals as the storage of maize for (3 and 6 months) at 0 KGy caused the increase in aflatoxin B1 by (5.00% and14.39%) for 3 and 6 months respectively, while with gamma radiation at 7 KGy the increase was (3.70% and 7.82%) and at 10 KGy the increase was (3.20% and 5.79%) for 3 and 6 months respectively, and for wheat at 0 KGy the increase in aflatoxin B1 was (5.70% and10.43%) while with gamma radiation at 7 KGy the increase was (1.74% and 2.76%) and at 10 KGy the increase was (1.02% and 1.41%) for 3 and 6 months respectively, with no significant increase in the toxin for wheat after 3 and 6 months in 7 and 10 KGy samples.
Ozone gas treatments
The storage of maize for (3 and 6 months) at 0 ppm caused the increase in aflatoxin B1 by (5.00 % and 14.39%) for 3 and 6 months respectively, while with ozone gas treatments at 70 ppm the increase was (3.32% and 9.28%) and at 100 ppm the increase was (2.30% and 2.5%) for 3 and 6 months respectively with a clear reduction in its formation, for wheat at 0 ppm the increase in aflatoxin B1 was (5.70% and10.43%) while with ozone gas treatment at 70 ppm the increase was (1.06% and 1.84%) and at 100 ppm the increase was (0.50% and 0.80%) with no significant increase in the toxin for maize at 100 ppm and wheat at 70 and 100 ppm after 3 or 6 months respectively.
According to these results 100 ppm is a suitable dose for storage for maize and wheat.
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B. With respect to proximate analyses:
The changes that occur in the proximate values was increased with increasing the dose levels with the highest reduction at 10 KGy samples for all proximates including ash, fat, protein and crude fiber except for moisture the highest reduction observed at 100 ppm where moisture reduced by 29.50% for maize and 22.80% for wheat and this help in the reduction of the fungus growth and accordingly aflatoxin.
C. With respect to fatty acid profiles:
After gamma radiation there were some significant changes in the fatty acid profile in maize and wheat, saturated fatty acid (palmitic acid) increased significantly at (7 and 10 KGy) while the mono-unsaturated fatty acid (oleic acid) and poly unsaturated fatty acid (linolenic acid) decreased, for maize palmitic acid increased significantly by (46.30% and 61.40%), oleic acid decreased by (39.30% and 55.60%) and linolenic acid decreased by (51.90% and 76.50%) at 7 and 10 KGy respectively. For wheat, palmitic acid increased significantly by (26.30% and 34.80%), oleic acid decreased by (13.57% and 20.98%) and linolenic acid decreased by (42.19 and 65.50) at 7 and 10 KGy respectively, with the higher reduction in case of maize.
After ozone gas treatments there were some significant changes in the fatty acid profile in maize only saturated fatty acid (palmitic acid) increased significantly at (70 and 100 ppm) while the mono-unsaturated fatty acid (oleic acid) decreased with no significant change in linolenic acid, palmitic increased significantly by (3.90% and 10.80%) and oleic decreased by (4.60% and 14.20%) at 70 and 100 ppm respectively. For wheat there was no statistical significant difference in the fatty acid profile.
The effect of ozone gas on the fatty acid profiles was less than that of gamma radiation at the studied doses.
With respect to B-complex vitamins:
There was a statistical significant change in the level of thiamine(B1) both in maize and wheat upon the use of gamma radiation and ozone gas treatments at (7 KGy, 10 KGy, 70 ppm and 100 ppm), for maize the % decrease were (16.30%, 46.50%, 4.65%, 9.30%) respectively and for wheat the % decrease were (14.30%, 42.86%, 3.75%, 10.71%) respectively.
According to the afford said data ozone gas at 100ppm is recommended in the removal of aflatoxin B1 to be within the legal limit, with slight or no decrease in the nutritive values than gamma radiation.