Lan Wenting, Li Siying, Shama Shiti, Zhao Yuqing, Sameen Dur E, He Li, Liu Yaowen
College of Food Science, Sichuan Agricultural University, Yaan 625014, China.
School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Polymers (Basel). 2020 Sep 15;12(9):2096. doi: 10.3390/polym12092096.
An antibacterial and anti-oxidation composite film was prepared by a casting method using sodium alginate (SA) and apple polyphenols (APPs) as the base material and glycerol as the plasticizer. Silver nanoparticles (AgNPs) were deposited by ultrasonic-assisted electrospray method. The degree of influence of the addition ratio of SA and AgNPs and different ultrasonic time on the mechanical properties, barrier properties, optical properties, and hydrophilicity of the composite film was explored. The composite films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the SA: AgNPs ratio of 7:3 and the ultrasonic time for 30 min have the best comprehensive performance, and SA/AgNPs/APP films showed the lowest water vapor permeability value of 0.75 × 10 g/m·s·Pa. The composite film has good strength and softness, with tensile strength (TS) and elongation at break (E) at 23.94 MPa and 29.18%, respectively. SEM images showed that the surface of the composite film was smooth and the AgNPs' distribution was uniform. The composite film showed broad antibacterial activity, and the antibacterial activity of (92.01%) was higher than that of (91.26%). However, due to the addition of APP, its antioxidant activity can reach 98.39%, which has a synergistic effect on antibacterial activity. For strawberry as a model, the results showed that this composite film can prolong the shelf life of strawberries for about 8 days at 4 °C, effectively maintaining their storage quality. Compared with the commonly used PE(Polyethylene film) film on the market, it has a greater fresh-keeping effect and can be used as an active food packaging material.
以海藻酸钠（SA）和苹果多酚（APPs）为基材、甘油为增塑剂，采用流延法制备了一种抗菌抗氧化复合膜。通过超声辅助电喷雾法沉积银纳米颗粒（AgNPs）。探讨了SA与AgNPs的添加比例以及不同超声时间对复合膜力学性能、阻隔性能、光学性能和亲水性的影响程度。采用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）和扫描电子显微镜（SEM）对复合膜进行表征。结果表明，SA:AgNPs比例为7:3且超声时间为30 min时综合性能最佳，SA/AgNPs/APP膜的水蒸气透过率最低，为0.75×10 g/m·s·Pa。复合膜具有良好的强度和柔软性，拉伸强度（TS）和断裂伸长率（E）分别为23.94 MPa和29.18%。SEM图像显示复合膜表面光滑，AgNPs分布均匀。复合膜具有广泛的抗菌活性，其对[具体菌1]的抗菌活性（92.01%）高于对[具体菌2]的抗菌活性（91.26%）。然而，由于添加了APP，其抗氧化活性可达98.39%，对抗菌活性具有协同作用。以草莓为模型，结果表明该复合膜在4℃下可将草莓的货架期延长约8天，有效保持其贮藏品质。与市场上常用的聚乙烯（PE）薄膜相比，其保鲜效果更佳，可作为一种活性食品包装材料。
