Research of the polyethylene packaging layer structure change in contact with a food product at exposure to ultraviolet radiation

Abstract

The sanitary and hygienic safety of modern packaging is determined by the layer of packaging material in direct contact with the food product. This layer in most cases is a synthetic polymer of the polyolefin class — low density polyethylene. This material is used as a stand-alone packaging and in multilayer and combined packaging materials. During thermal and photooxidation, compounds can form in it that negatively affect the safety of the package, which can migrate into the product. Food technologies use methods of disinfecting packaging materials and packaging before filling or bottling products. These methods include ultraviolet irradiation of the surface, which has a bactericidal effect. Using spectral methods of analysis, researches have been carried out on changes in the polyethylene layers structure in the film’s composition, multilayer films and combined packaging materials when exposed to pulsed ultraviolet radiation in a wide spectral range (irradiation with a pulsed xenon lamp). Deformations of polyethylene macromolecules chemical bonds on the surface and boundary layers under the influence of pulsed UV-irradiation have been revealed. The IR spectra of ATR (Attenuated Total Reflection) were obtained, the analysis of which showed that the monofilm is subject to the greatest destructive effect, as evidenced by the appearance of characteristic absorption bands responsible for the formation of aldehyde, ketone groups, as well as for the polymer chain termination. It is shown that the use of food soot in the composition of multilayer packaging films blocks their photo destruction. Upon irradiation of a combined material based on cardboard intended for bottling milk, an absorption band was found in the spectra, which is responsible for the onset of the destruction process with the formation of aldehyde and carboxylate groups with the formation of aldehyde and carboxylate groups.Comparison of changes in structure in three different packaging objects containing a polyethylene layer shows the feasibility and necessity of using combined and multilayer materials for food products packaging, in which, even under extreme UV-irradiation, there are practically no photo destruction processes, which is confirmed by spectral researches.