为了开发新型的抗氧化活性包装材料，该文以壳聚糖/绿茶多酚构成的复合膜为研究对象，比较分析了甘油和聚乙二醇对壳聚糖膜物理、机械、抗氧化和结构特性的影响。结果表明：未加入绿茶多酚前，壳聚糖甘油膜有着较低的水蒸汽透过系数和膨胀程度，其水蒸汽透过系数为8.84×10-11g/(m·s·Pa)。然而，聚乙二醇膜的抗拉强度和穿透力均高于甘油形成的膜。X射线衍射分析（XRD）表明应用质量分数40%的增塑剂导致11.7°和17.9°出现2个结晶峰，分别对应壳聚糖的水合结晶和无水结晶。加入绿茶多酚后，壳聚糖复合膜的抗氧化能力显著提高，1,1-二苯基-2-苦基肼（DPPH）自由基清除能力在5 min内达到83.9%。加入绿茶多酚显著降低了膜溶液的表观黏度，增加了膜的厚度、颜色和阻水性。从2种增塑剂的对比效果看，绿茶多酚对于甘油膜的机械性能影响较大，其断裂伸长率从42.02%急剧下降到9.19%，并且使膜的结晶结构从水合状态转变为非晶状态。但绿茶多酚对聚乙二醇膜的水蒸汽透过系数、膨胀程度和颜色影响较大。壳聚糖复合膜性能的这种差异与增塑剂中所含羟基的数量以及与绿茶多酚的配比有关。研究结果为绿茶多酚复合包装膜在实际中的应用提供了理论依据。% Green tea polyphenols, which are extracted from tea and contain catechin, flavones, anthocyan, and phenolic acid, have been generally demonstrated to be powerful antioxidants. The development of antioxidant active packaging materials by the incorporation of tea polyphenols into biocompatible polysaccharide film has aroused significant interest. In order to broaden the application of chitosan film and develop environment-friendly composite film with green tea polyphenols, the effects of green tea polyphenols and plasticizer such as glycerol and polyethylene glycol 200 on the physical, mechanical, antioxidant, and structural properties of the chitosan films were investigated. The composite film-forming solutions were prepared by dispersing chitosan (2%) in an aqueous solution of 1%glacial acetic acid. As for the film, 5 g/L of green tea polyphenols as the active additive, 8 g/L of glycerol and polyethylene glycol 200 as the plasticizer were added into the solutions. Results showed that two kinds of plasticizer had little effect on the apparent viscosity of film-forming solutions without green tea polyphenols. The chitosan/glycerol/ polyethylene glycol (CGP) film had a lower water-vapor permeability (8.84×10-11g/(m·s·Pa)) and swelling degree compared with the polyethylene glycol film. However, the tensile strength and puncture strength of polyethylene glycol based-film were significantly higher than those of the film formed by the glycerol. The greatest tensile strength and puncture strength were 31.05 MPa and 19.26 N, respectively, which were observed in the CGP film. In addition, X-ray diffraction (XRD) analysis indicated the use of 40% plasticizer (w/w chitosan) caused higher crystallinity, displaying clear diffraction peaks around 2θ=11.1° and 17.9° due to the hydrated crystal and anhydrous crystal of chitosan film, respectively. No significant changes were found in film crystallinity between two kinds of plasticizer-based composite film. With the addition of green tea polyphenols, the antioxidant ability of the chitosan composite film was significantly improved, and the DPPH radical scavenging activity reached 83.9% within 5 min. Moreover, the addition of green tea polyphenols significantly decreased the apparent viscosity of film-forming solutions and increased the thickness and color of film. The water vapor permeability of chitosan composite film was significantly decreased, and the lowest value was 3.38×10-11 g/(m·s·Pa) in chitosan/ polyphenols/glycerol/polyethylene glycol (CTGP) film. Comparing the two plasticizers, green tea polyphenols had a greater impact on the mechanical properties of the glycerol composite film. The elongation at break of CG film decreased significantly from 42.02% to 9.19%. Moreover, the crystal structure of CG film was changed from hydrated and anhydrous state to the amorphous state with the addition of green tea polyphenols. As for the CP film, the addition of green tea polyphenols caused significant changes in water vapor permeability, swelling degree and color. The release of antioxidants from CTP composite film was slower than that from CTG film. In a word, the differences in chitosan composite films were related to the number of hydroxyl groups contained in the plasticizer and the blend ratio of green tea polyphenols. So the blend of plasticizer and green tea polyphenols could be selected to prepare the film according to different specifications. The study results could provide theoretical references for the application of green tea polyphenols composite films.
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