| Radiation processing technique is one of the state of the art methods, which has been became an effective way to ensure food safety. With the development of food irradiation, the safety of irradiated packaging materials for food is gaining more and more attention. As directly contacting with food, packaging materials tend to degrade during irradiation. The degraded products, the small molecules, can migrate into food, which cause the safety problems of the food. Thus, the study on the irradiation behaviors of flexible multilayer packaging is timely and meaningful.Three kinds of 60Co-γ-irradiation food packaging PE films were chosen in this study. The main research contents and results are shown as follows.1. An analytical method based on headspace gas chromatography mass spectrometry(HS-GC-MS) was developed to determine 18 organic solvent residues in food packaging. The results show that the method has good liner relationship(r>0.9999), with LOD between 0.04~0.16 ug, 91.6 %~105.7 % average recovery rate, and less than 9.5 % RSD for 18 compounds. The method can be used to quantitatively analyze 18 organic solvent residues in 3 kinds of food packaging, The results show that the content of ethyl acetate is higher than the other residues.2. Using HS-GC-MS analysis method, the organic solvent residues were determined for three kinds of food packaging after 2~50 k Gy dose irradiation. The results show that small molecules, such as alcohols, carbonyl compounds, esters appear in the irradiated food-grade multilayer- films. With the increase of irradiation dose, the contents of carbonyl compounds and alcohols increase, the contents of ethyl acetate decrease. It suppose that during the irradiation process, esters be degraded; the carbon-oxygen bonds are broken to form alcohols and carbonyl compounds. Compared with the butanone, acetone is more easily to be degraded. Under the small dosage, acetone was produced, while butanone was produced under the irradiation more than 20 k Gy. When the dose of irradiation more than 50 k Gy, traces benzene was produced in PA/PE films, it should be supposed that some additives or auxiliary in films were degraded. With the 60Co-γ-irradiation of 2~50 k Gy, 4 new compounds appeared: n-hexane,aldehyde and isoamyl alcohol.3. An analytical method was established based on gas chromatography mass spectrometry(GC-MS) for determining 3 antioxidants(BHA, BHT and TBHQ) in food packaging. The results show that the method for these three kind antioxidants has a good relationship in the range of 0.5~40 mg/L, and its correlation coefficients better than 0.997. The detection limits are 0.14, 0.03 and 1.04 mg/kg, respectivily. The average recovery rate is from 90.6 % to 99.0 %, and the relative standard deviation(n=6) is less than 9.0 %. Using the method to determin 3 compounds in 3 kinds of food-grade PE films, the results show that the content of antioxidant-BHT is higher in films, while BHA and TBHQ can not be detected.4. By GC-MS analysis method, the content of three kind antioxidants and their migration in 3 kinds of irradiated food-grade PE films were determined under 2~50 k Gy dose irradiation. The results show that with the increase of irradiation dose, the contents and migration levels of antioxidant-BHT decrease while the contents and migration levels of 1,3-DTBB increase, and antioxidants-BHT is fat soluble.5. According to the national standards, the evaporation residue, potassium permanganate consumption and heavy metal-Pb were determined for 3 kinds of foodgrade PE films with 0~50 k Gy irradiation. With the increase of irradiation dose, the contents of evaporation and heavy metal-Pb almost not change, whereas the content of the potassium permanganate consumption increases slowly, may be produced by the chain reaction degradation-occurred in the films.6. According to the national standards, the maximum force and elongation at break, oxygen permeability and water vapor permeability of three kinds of food-grade PE films were determined with 0~50 k Gy irradiation. With the increasing of irradiation dose, the maximum force, elongation, oxygen permeability and water vapor permeability all first increase and then decrease. But one of the films of PP/AL/PE is different with the others, because of the aluminum foil- which indicates that the alumium film has compl ex influence on 60Co-γ-irradiation. |
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