Li Wenxin, Zhao Mengna, Xia Xiufang, Zhu Yingchun
College of Food Science, Northeast Agricultural University, Harbin 150030, China.
College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China.
Foods. 2024 Aug 6;13(16):2477. doi: 10.3390/foods13162477.
Sodium alginate (SA)-purple sweet potato peel extracts (PPE) from industrial waste indicator films were developed at different drying temperatures (25, 30, 35, 40, 45, 50, and 55 °C). The effects of drying temperatures on the film's structural, physical, and sensitive properties were investigated. On the structural properties, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction indicated that compactness, intermolecular interactions, and crystallinity of indicator films were improved at a lower drying temperature. On the physical properties, with the drying temperature increasing, elongation at the break increased significantly ( < 0.05); ΔE and water-vapor permeability decreased significantly ( < 0.05); and thickness and tensile strength initially increased significantly (90.46 → 98.46, 62.99 → 95.73) and subsequently decreased significantly (98.46 → 71.93, 95.73 → 55.44) ( < 0.05), with the maximum values obtained at 30 °C. On sensitivity, the corresponding colors of the films became lighter as the drying temperature increased, and the films exhibited relatively excellent pH and NH sensitivity, with easily discernible color changes at lower temperatures. The results of this paper revealed that the overall film characteristics are improved at lower drying temperatures, which will provide valuable references for selecting the drying temperature for preparing indicator films as a guide for industrialized production.
以工业废弃物为原料，在不同干燥温度（25、30、35、40、45、50和55℃）下制备了海藻酸钠（SA）-紫薯皮提取物（PPE）指示膜。研究了干燥温度对膜的结构、物理和敏感性能的影响。在结构性能方面，扫描电子显微镜、傅里叶变换红外光谱和X射线衍射表明，较低干燥温度下指示膜的致密性、分子间相互作用和结晶度得到改善。在物理性能方面，随着干燥温度升高，断裂伸长率显著增加（<0.05）；ΔE和水蒸气透过率显著降低（<0.05）；厚度和拉伸强度最初显著增加（90.46→98.46，62.99→95.73），随后显著降低（98.46→71.93，95.73→55.44）（<0.05），在30℃时达到最大值。在敏感性方面，随着干燥温度升高，膜的相应颜色变浅，膜表现出相对优异的pH和NH敏感性，在较低温度下颜色变化易于辨别。本文结果表明，较低干燥温度下膜的整体特性得到改善，这将为制备指示膜的干燥温度选择提供有价值的参考，为工业化生产提供指导。
