Abstract Transparent and colorless citric acid-incorporated fish gelatin/chitosan composite films were prepared in this work. The addition of citric acid into film forming formulations slowed down the swelling rate and swelling values of the films, which maintained their integrity and resulted in flexible hydrated films. Furthermore, citric acid acted as plasticizer, increasing the elongation at break of the films. Additionally, films showed good UV barrier properties and the incorporation of citric acid and chitosan reduced the E. coli growth, especially for the films prepared with 20 wt % citric acid, highlighting the potential use of these films as active food packaging. These results were related to the changes observed by Fourier transform infrared (FTIR) analysis, which revealed the different protein structure achieved as a function of citric acid and chitosan contents.

中文翻译：

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掺柠檬酸鱼明胶/壳聚糖复合膜

摘要 本工作制备了透明无色的掺入柠檬酸的鱼明胶/壳聚糖复合薄膜。在成膜配方中加入柠檬酸减缓了薄膜的溶胀速率和溶胀值，从而保持了它们的完整性并产生了柔韧的水合薄膜。此外，柠檬酸作为增塑剂，增加了薄膜的断裂伸长率。此外，薄膜显示出良好的紫外线阻隔性能，柠檬酸和壳聚糖的掺入减少了大肠杆菌的生长，特别是对于用 20 wt% 柠檬酸制备的薄膜，突出了这些薄膜作为活性食品包装的潜在用途。这些结果与傅里叶变换红外 (FTIR) 分析观察到的变化有关，