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Abstract
Many International organizations especially the International Commission of Radiation Protection ICRP (1991) are concerned with the protection against ionizing radiation. High level of radiation has received more insight than low level. Such interest increased after the accident of Chernobyl and Hiroshima, which lead to tremendous hazardous effects in human, animal, plant as well as the environment.
Also the wide use of Radiation in different fields, medicine, manufacture and agriculture in addition to the increase in the use of nuclear power plant make accurate assessment to neutron Radiation hazard monitory.
Little information are available on the biological effect of low level doses of neutrons because most of the early and Recent studies were concerned with the biological effect of high level doses.
Therefore, the effect of low level doses of fast neutrons on the structure properties of some foodstuff material are of scientific and public interest.
Egyptian rice grains (Shake 102) was used, since it is the major food crops, not only in Egypt but also in the world.
Rice protein is more easily assimilated than wheat protein, therefore this rice may be more acceptable to diabetics (Anon, 1965). Also, rice compares favorably with other cereals in amino – acid content and digestibility of the protein is high, being 96.5 for the whole grain and 98 percent for milled rice, in addition to that it contains 72.2 to 74.9 percent starched (Carbohydrate) (Grist, 1975).
In the present work, we studied the effect of low level doses of fast neutrons, in the range 120 ? 1000 MSV (105 ?? 109 n / cm2) on the Egyptian rice (Shake 102) grains. This study includes two main parts. The first one, was to study the changes in the molecular structure of the water soluble protein (WSP) extracted from the mother (M) and first generation (M1) Rice grains due to the irradiation process. This was achieved through measuring each of their dielectric relaxation in the frequency range 0.1 ?? 5 MHz, and the molecular weight distribution (subunit structure) by using SDS polyacrylamid gel electrophoresis (SDS–PAGE). From the figures and the data, the molecular radii R, relaxation time ?, relative permittivity ?’, dielectric loss ?’’, electric conductivity ?, Cole – Cole parameter ? and the molecular weight distribution of the protein molecules were measured and calculated.
In the second part, the effect of the same low level neutron fluences on the mother grains (M), growth character and the yield of the first generation grains (M1) were studied. Some morphological properties such as the stem length, number of pencial per plant and the average weight of 100 grains, no. of grain per penical were investigated. Also the physiological parameters such as the chlorophyll pigment content, the total sugar content, the relative concentration levels of some minerals and the water soluble protein concentration was measured for the mother and the first generation grains.
The results indicate that there are changes in the molecular structure of the (WSP) molecules, these changes and be analysed from the results of dielectric increment ??’, the relaxation time ?, the molecular radii (R), the conductivity ?, and Cole – Cole parameter (?) due after irradiation. The same effect is to be observed for both of the subunit structure of WSP and its molecular weight distribution. In addition the (WSP) concentration increased by irradiation with the neutron fluence 3×106 n/cm2 relative to the other fluences.
Furthermore, the yield of the first generation increased after the irradiation with neutron fluence 3×106 n/cm2. The results also showed a decrease in the iron content to about 50% for M1 grains relative to the unirradiated. However, Zinc appeared in the grains of the first generation whose mothers grains were exposed to 3×106 n/cm2.
It was concluded from the present work that exposure of rice grain to such low level doses of fast neutrons leads to increasing the yield and the protein content of its grains especially the neutron fluence 3×106 n/cm2. The increase of the yield after irradiation leads to an interesting point which will be of economic interest