| This study regarded rice as reach object which was irradiated by high energy electron beam,under different irradiation doses,researched the different concentrations of chlorpvrifos,isoprothiolane,propanil,tricycalzole,dimethote,pymetrozine and monosultap 7 common pesticides degradation rates in rice,proven the concretion-response relationship between irradiation dose and degradation effect of 7 pesticides,analyzed the degradation products and toxicity of degradation products;researched the change rules of the total number of colonies,coli form,mold and yeast in rice and the effect about irradiation dose for main microorganisms in rice store,to provide reference for high energy electron beam irradiation using in grain foods.The results showed:1?High energy electron beam could reduce the residues of chlorpvrifos,isoprothiolane,propanil and tricycalzole,the degradation effects of pymetrozine and monosultap were not obviously.Under these experimental conditions,after 3kGy irradiated,dimethote was not checked out,after 5kGy irradiated,chlorpvrifos,isoprothiolane,propanil and tricycalzole were not checked out.2?Irradiation dose of high energy electron beam played a main role of pesticides residues in rice.(1)As for chlorpvrifos,tricycalzole,propanil and dimethote,irradiation dose was positively related with pesticide degradation rate.When the irradiation dose goes from 1kGy to 5kGy,the pesticides residues of chlorpvrifos and tricycalzole which residues was 10mg/kg became 27.0% and 21.9% to 36.0% and 32.7%;lower dose of high energy electron beam could implement better degradation rates about propanil,under 1kGy,1mg/kg propanil degradation rate was already 36.2%.The degradation rate of dimethote had positively related with concentration and radiation dose,under 5kGy,the degradation rate of three kinds of concentrations dimethote were 28.8%,36.4%,45.9%;(2)Under 3kGy high energy electron beam,the isoprothiolane degradation rate was the highest.When the irradiation dose increased,the tendency about degradation rates of three kinds of isoprothiolane became first increased and then decreased.(3)High energy electron beam degraded effects about pymetrozine and monosultap were not obvious.Under 5kGy,1mg/kg,5mg/kg,10mg/kg pymetrozine and monosultap degradation rates were all under 7%.3?Analyzed the degradation products of 5 kinds of pesticides which had high degradation rates after irridiated,analyzed three kinds of degradation products of propanil,namely 3,4-Dichloro-N-methylaniline,3,4-Dichloroacetanilide and 3,4-Dichloroaniline;two kinds of degradation products of chlorpvrifos,namely O,O,O',O'-Tetraethyldithiopyro phosphate and 3,5,6-Trichloro-2-pyridinol;two kinds of degradation products of dimethote,namely O,O,S-Trimethyl phosphorothioate and O,O-Dimethyl dithiophosphorylacetic acid N-methyl-N-formylamide;one kind of degradation products of isoprothiolane and tricycalzole,namely 1,3-Dithiol-2-ylidenepropanedioic acid bis(1-methylethyl)ester and 2-Amino-4-methylbenzothiazole.4?Different dose of high energy electron beam had different killing affections about the microbial in rice.(1)Under 1kGy,3kGy,5kGy,the total number of colonies and killing rates were 3.27 log CFU/g,2.95logCFU/g,1.17logCFU/g and 90.3%,97.4% and 98.7%,high energy electron beam made them keeping the same order of magnitude within at least a month and a half.(2)3kGy high energy electron beam had good killing effect of the number of coli form and yeast.Under 1kGy,3kGy,5kGy,the number of coli form and yeast were 1.19logCFU/g,0.85logCFU/g,0.33logCFU/g and 1.34 log CFU/g,0.47logCFU/g,0.33logCFU/g,the killing rates were 79.3%,88.4%,99.8% and 88.6%,89.4%,99.3%.(3)High energy electron beam killing effect of mould in rice was obviously.Under 1kGy,3kGy,5kGy,the total number and killing effects of mould were 2.01 log CFU/g,1.31logCFU/g,0.33logCFU/g ? 87.5%,94.9%,99.8%.1kGy high energy electron beam made it keeping the same order of magnitude within at least three months. |
PDF Full Text Request