Here, we prepared ionically crosslinked films using pectin extracted from agro-wastes, specifically ambarella peels (AFP) and jackfruit seed slimy sheath (JFS). Physiochemical properties of pectins, including moisture content, molecular weight (Mw), degree of esterification (DE), and galacturonic acid (GA), were analyzed. Optimal extraction was determined, i.e., citric acid concentration 0.3 M, time 60 min, solid/liquid ratio 1:25, and temperature 90 °C for AFP or 85 °C for JFS. Pectin yields under these conditions were 29.67 % ± 0.35 % and 29.93 ± 0.49 %, respectively. AFP pectin revealed Mw, DE, and GA values of 533.20 kDa, 67.08 % ± 0.68 %, and 75.39 ± 0.82 %, while JFS pectin exhibited values of 859.94 kDa, 63.04 % ± 0.47 %, and 78.63 % ± 0.71 %, respectively. The pectin films crosslinked with Ca, Cu, Fe, or Zn exhibited enhanced tensile strength and Young's modulus, along with reduced elongation at break, moisture content, water solubility, water vapor permeability, and oxygen permeability. Structural analyses indicated metal ions were effectively crosslinked with carboxyl groups of pectin. Notably, the Cu-crosslinked film demonstrated superior water resistance, mechanical properties, and exhibited the highest antioxidant and antibacterial activities among all tested films. Therefore, the pectin films represent a promising avenue to produce eco-friendly food packaging materials with excellent properties.

中文翻译：

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从安巴雷拉果皮和菠萝蜜种子粘液鞘中提取的新型果胶膜：离子交联对果胶膜性能的影响

在这里，我们使用从农业废物中提取的果胶制备了离子交联薄膜，特别是安巴雷拉果皮（AFP）和菠萝蜜种子粘液鞘（JFS）。分析了果胶的理化性质，包括水分含量、分子量（Mw）、酯化度（DE）和半乳糖醛酸（GA）。确定了最佳提取条件，即柠檬酸浓度0.3 M，时间60 min，固液比1:25，AFP温度90℃，JFS温度85℃。这些条件下的果胶产率分别为 29.67 % ± 0.35 % 和 29.93 ± 0.49 %。 AFP 果胶的 Mw、DE 和 GA 值分别为 533.20 kDa、67.08 % ± 0.68 % 和 75.39 ± 0.82 %，而 JFS 果胶的值分别为 859.94 kDa、63.04 % ± 0.47 % 和 78.63 % ± 0.71 %。与 Ca、Cu、Fe 或 Zn 交联的果胶膜表现出增强的拉伸强度和杨氏模量，同时降低断裂伸长率、水分含量、水溶性、水蒸气渗透性和氧渗透性。结构分析表明金属离子与果胶的羧基有效交联。值得注意的是，铜交联薄膜表现出优异的耐水性和机械性能，并且在所有测试的薄膜中表现出最高的抗氧化和抗菌活性。因此，果胶薄膜是生产具有优异性能的环保食品包装材料的一条有前途的途径。