四川大学生物质与皮革工程系田永强教授团队在Food Hydrocolloids发表题目为“Improvement of mechanical and bioactive properties of chitosan films plasticized with novel thymol-based deep eutectic solvents”研究论文（用新型百里酚基深共熔溶剂增塑壳聚糖膜的机械和生物活性性能的改善）。
摘要：
壳聚糖 (CS) 的机械性能和阻隔性能有限，限制了其在食品包装中的广泛应用。为了克服这一挑战，提出了一种简单的方法，使用新型深共熔溶剂 (DES) 制备多功能生物活性 CS 包装膜。DES 最初由薄荷醇 (ME)、辛酸 (OA) 和百里酚 (THY) 制备而成。通过FTIR和1H NMR分析验证了3种DES（OA：THY、ME：THY和OA：ME：THY）制备成功，并研究了DES的组成和添加量（0.5、1.0和1.5%）对CS膜结构、功能性能的影响。流变分析、FTIR、XRD、SEM结果表明DES与CS基质之间具有良好的生物相容性及有效的分子间相互作用。CS-DES复合膜的热稳定性随DES含量的增加而降低。DES的加入显著提高了膜的机械强度和疏水性。CS-ME:OA:THY-0.5复合膜的拉伸强度最高（69.34 MPa），CS-ME:OA:THY-1.5复合膜的疏水性最强（水接触角=107.95°）；随着DES含量的增加，薄膜的透光率有所下降，尤其对于紫外线阻隔性较强的CS-ME:OA:THY-1.5复合膜。此外，CS-DES复合膜表现出优异的抗菌活性（24小时内抑制率为96%）、抗氧化活性和生物安全性。最后，CS-ME:OA:THY复合膜可有效延长葡萄保质期3天。测试的DES代表了改善CS基膜缺陷的有前途的增塑剂。这项工作为CS-DES复合膜在食品相关领域的实际应用铺平了道路。
研究结果：
3.1 DES的合成与表征
Fig. 1. Schematic illustration of preparation of DES and CS-DES composite films (A), FTIR spectra of DES constituents and DESs (B), 1H NMR spectra of OA:THY (C), ME:THY (D) and OA:ME:THY (E).
3.2 CS-DES成膜溶液的流变性能
Fig. 2. Apparent viscosity of film-forming solution containing 0.5% (A), 1.0% (B) and 1.5% (C) of DESs (DES/chitosan solution (2%, w/v), w/v).
3.3. CS-DES复合膜的表征
3.3.1. SEM
Fig. 3. SEM images of the surface, fractured cross-sections of films containing 0.5%, 1.0% and 1.5% of different DESs (DES/chitosan solution (2%, w/v), w/v).
3.3.2. XRD
3.3.3. FTIR
Fig. 4. XRD patterns (A), FTIR spectra (B–D) of films containing 0.5%, 1.0% and 1.5% of different DESs (DES/chitosan solution (2%, w/v), w/v).
3.3.4. 热稳定性分析
Fig. 5. TGA curves (A–C) and corresponding DTG curves (D–F) of films containing 0.5%, 1.0% and 1.5% of different DESs (DES/chitosan solution (2%, w/v), w/v).
3.3.5 薄膜厚度与机械性能
3.3.6. 薄膜的 WS、WCA 和 WVP
Fig. 6. The thickness (A), TS (B), EB (C), WS (D), WCA (E) and WVP (F) of films containing 0.5%, 1.0% and 1.5% of different DESs (DES/chitosan solution (2%, w/v), w/v).
3.3.7. 颜色和光学特性
Fig. 7. Visual appearance (A), light transmission characteristics (B–D) of films containing 0.5%, 1.0% and 1.5% of different DESs (DES/chitosan solution (2%, w/v), w/v).
3.4. 抗菌活性
Fig. 8. Bacterial growth curves (A and C), corresponding antibacterial efficiencies (B and D), inhibition zone diameters (E and F) of E. coli and S. aureus treated with CS-DES composite films.
3.5. 抗氧化活性
3.6 安全评价
Fig. 9. Effect of control and CS-DES films on DPPH scavenging activity (A) and ABTS scavenging activity (B), The antioxidant mechanism diagram of CS-DES composite films (C), Cell viability and representative confocal laser scanning fluorescence images of L929 cells treated with films containing 0.5 %, 1.0 % and 1.5 % of different DESs (DES/chitosan solution (2%, w/v), w/v, D and E).
3.7. 水果保鲜
Fig. 10. Schematic diagram of CS-DES composite films for grapes preservation (A), weight loss (B), total soluble solids (C) and firmness (D) of grapes in different treatment groups during storage (0–9 Day).
