北五味子提取物/壳聚糖复合膜的制备及其在肉丸贮藏中的应用

目的 改善纯壳聚糖可食用膜存在的溶胀度高、抗氧化活性不足等缺陷, 使用共混改性的方式提升膜的性能。方法 以壳聚糖为成膜基质, 甘油为增塑剂, 添加北五味子提取物, 采用流延法制备可食用复合膜。研究北五味子提取物的添加量对复合膜的结构特征、物理性能、抗氧化和抑菌活性的影响, 通过傅里叶红外光谱、X-射线衍射、扫描电镜等对复合膜的性能进行表征, 并对经涂膜处理的肉丸进行贮藏实验。结果 北五味子提取物与壳聚糖混合后能保留原有结构, 复合膜的抗氧化活性、阻湿性、阻光性与机械性能得到明显提升。与对照组相比, 在最优添加量时, 复合膜的1,1-二苯基-2-三硝基苯肼自由基清除活性明显提高, 在50%乙醇溶剂中表现最好; 水蒸气透过系数降低了60.20%; 不透明度与北五味子提取物添加量呈正相关; 拉伸强度由7.38 MPa提升至9.92 MPa。将复合膜应用在肉丸贮藏中, 经涂膜处理的肉丸挥发性盐基氮值和菌落总数皆低于对照组, 表现出较好的微生物抑制作用, 肉丸保质期最长可达15 d。结论 北五味子提取物的添加改善了复合膜的性能, 抑菌效果得到提升, 本研究可为壳聚糖基膜的制备及其在肉制品上的应用提供一定数据参考。

Preparation of Schisandra chinensis extract/chitosan composite film and its application in meatball storage

Objective To improve the defects such as high swelling degree and insufficient antioxidant activity of pure chitosan edible membrane, and use blending modification to improve the performance of the membrane. Methods Chitosan was used as film-forming matrix, glycerol was used as plasticizer, and Schisandra chinensis extract was added, and the edible composite film was prepared by casting method. The effects of the addition amount of Schisandra chinensis extract on the structural characteristics, physical properties, antioxidant and antibacterial activities of the composite films were studied, and the properties of the composite films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The storage experiments were carried out on the coated meatballs. Results The original structure of Schisandra chinensis extract could be retained after mixing with chitosan, and the antioxidant activity, moisture barrier, light barrier and mechanical properties of the composite film were significantly improved. Compared with the control group, at the optimal dosage, the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of the composite film was significantly improved, and the best performance was in 50% ethanol solvent; the water vapor transmission coefficient was reduced by 60.20%; there was a positive correlation with the amount of material added, the tensile strength was increased from 7.38 MPa to 9.92 MPa. The composite film was applied to the storage of meatballs. The volatile base nitrogen value and total number of colonies of the coated meatballs were lower than those of the control group, showing better microbial inhibition. The quality guarantee period of the meatballs could reach up to 15 d at most. Conclusions The addition of Schisandra chinensis extract improves the performance of the composite film and improves the bacteriostatic effect. This study can provide some data reference for the preparation of chitosan-based film and its application in meat products.