Chen Chen, Du Yan, Zuo Guanjie, Chen Fusheng, Liu Kunlun, Zhang Lifen
College of Food Science and Technology, Henan University of Technology, Zhengzhou, Henan Province 450001, People's Republic of China.
R Soc Open Sci. 2020 Feb 12;7(2):191777. doi: 10.1098/rsos.191777. eCollection 2020 Feb.
The functional properties of biopolymer-based film packaging materials are susceptible to external storage conditions. The effects of different storage temperature, relative humidity (RH) and duration on the apparent form, barrier properties, mechanical properties and microstructure of corn-wheat starch/zein bilayer films were studied. From 0 to 150 days, storage temperature and RH, but not storage time, affected the appearance and colour of the bilayer films. The increase in haze of the bilayer films stored at 25°C was much greater than that at low temperatures. With increased storage time, the moisture content first increased and then decreased, while the water resistance and oxygen barrier properties of the bilayer films worsened. After 150 days, the bilayer film stored at 25°C with 54% RH had better water resistance properties. The oxygen barrier properties of the bilayer film stored at 25°C with 43% RH were preferable to those of other groups because the peroxide value of vegetable oil packed in the former bilayer film was the lowest. The tensile strength of bilayer films stored at 25°C with RH of 43, 54 and 65% decreased, but was still better than those stored at low temperatures (-17°C, 4°C), which were tough due to their high elongation at break. Scanning electron microscopy results showed tight bonds between the bilayer films, and the network structure inside the films disappeared and reappeared during storage. The cross-sectional compactness changed, and there was no film separation after 150 days.
基于生物聚合物的薄膜包装材料的功能特性易受外部储存条件影响。研究了不同储存温度、相对湿度（RH）和持续时间对玉米-小麦淀粉/玉米醇溶蛋白双层薄膜的表观形态、阻隔性能、机械性能和微观结构的影响。在0至150天内，储存温度和RH而非储存时间影响双层薄膜的外观和颜色。在25°C下储存的双层薄膜雾度增加幅度远大于在低温下的增加幅度。随着储存时间增加，双层薄膜的水分含量先增加后降低，而其耐水性和氧气阻隔性能变差。150天后，在25°C和54%RH条件下储存的双层薄膜具有更好的耐水性能。在25°C和43%RH条件下储存的双层薄膜的氧气阻隔性能优于其他组，因为用前一种双层薄膜包装的植物油的过氧化值最低。在25°C和43%、54%和65%RH条件下储存的双层薄膜的拉伸强度降低，但仍优于在低温（-17°C、4°C）下储存的薄膜，后者因高断裂伸长率而坚韧。扫描电子显微镜结果显示双层薄膜之间有紧密结合，薄膜内部的网络结构在储存过程中消失并重新出现。横截面致密性发生变化，150天后没有薄膜分离现象。
