Pant Astrid F, Sängerlaub Sven, Müller Kajetan
Chair of Food Packaging Technology, Technical University of Munich, Weihenstephaner Steig 22, 85354 Freising, Germany.
Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Str. 35, 85354 Freising, Germany.
Materials (Basel). 2017 May 3;10(5):489. doi: 10.3390/ma10050489.
Oxygen scavengers are used in food packaging to protect oxygen-sensitive food products. A mixture of gallic acid (GA) and sodium carbonate was used as an oxygen scavenger (OSc) in bio-based multilayer packaging films produced in a three-step process: compounding, flat film extrusion, and lamination. We investigated the film surface color as well as oxygen absorption at different relative humidities (RHs) and temperatures, and compared the oxygen absorption of OSc powder, monolayer films, and multilayer films. The films were initially brownish-red in color but changed to greenish-black during oxygen absorption under humid conditions. We observed a maximum absorption capacity of 447 mg O₂/g GA at 21 °C and 100% RH. The incorporation of GA into a polymer matrix reduced the rate of oxygen absorption compared to the GA powder because the polymer acted as a barrier to oxygen and water vapor diffusion. As expected, the temperature had a significant effect on the initial absorption rate of the multilayer films; the corresponding activation energy was 75.4 kJ/mol. Higher RH significantly increased the oxygen absorption rate. These results demonstrate for the first time the production and the properties of a bio-based multilayer packaging film with GA as the oxygen scavenger. Potential applications include the packaging of food products with high water activity (a > 0.86).
氧气清除剂用于食品包装，以保护对氧气敏感的食品。没食子酸（GA）和碳酸钠的混合物被用作氧气清除剂（OSc），用于通过三步工艺生产的生物基多层包装薄膜中：混合、平膜挤出和层压。我们研究了薄膜表面颜色以及在不同相对湿度（RHs）和温度下的氧气吸收情况，并比较了OSc粉末、单层薄膜和多层薄膜的氧气吸收情况。薄膜最初呈棕红色，但在潮湿条件下吸氧过程中变为绿黑色。我们观察到在21°C和100%RH下的最大吸收容量为447mg O₂/g GA。与GA粉末相比，将GA掺入聚合物基质中降低了氧气吸收速率，因为聚合物起到了氧气和水蒸气扩散的屏障作用。正如预期的那样，温度对多层薄膜的初始吸收速率有显著影响；相应的活化能为75.4kJ/mol。较高的RH显著提高了氧气吸收速率。这些结果首次证明了以GA作为氧气清除剂的生物基多层包装薄膜的生产及其性能。潜在应用包括包装水分活度高（a>0.86）的食品。
