Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research , Chinese Academy of Sciences , Yantai , Shandong 264003 , People's Republic of China.
University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China.
J Agric Food Chem. 2019 Mar 6;67(9):2530-2539. doi: 10.1021/acs.jafc.8b04567. Epub 2019 Feb 21.
Chitosan ascorbates with different substitution degrees were synthesized on the basis of salification of chitosan and ascorbic acid at various molar ratios in water and were successfully used to prepare antioxidative films by casting for the first time. Fourier transform infrared and H nuclear magnetic resonance spectra recorded the structural characteristics of all chitosan ascorbates; meanwhile, physicochemical property and antioxidant activity of the produced chitosan ascorbate films were characterized, with chitosan acetate film serving as the control, and these properties were also measured for comparison. The results revealed that salification of chitosan with ascorbic acid not only improved the total color difference, chroma, opacity, capacity for blocking ultraviolet-visible light, and water solubility of chitosan-based films but also decreased water content, swelling degree, and water vapor permeability compared to chitosan acetate film. Also, as was expected, the antioxidant activity assays showed that incorporation of ascorbate into the chitosan matrix effectively enhanced the scavenging activity against the DPPH radical and reducing power. CsVc and CsVc especially exhibited the strongest scavenging capacities against the DPPH radical (EC < 0.025 mg/mL). These findings offered a suggestion that the prepared chitosan ascorbate films can be applied as novel green oxidation-resistant materials in the food packaging industry.
基于壳聚糖和抗坏血酸在不同摩尔比下水溶液中的盐化反应，合成了不同取代度的壳聚糖抗坏血酸盐，并首次成功地通过浇铸法将其用于制备抗氧化膜。傅里叶变换红外和 H 核磁共振谱记录了所有壳聚糖抗坏血酸盐的结构特征；同时，对所制备的壳聚糖抗坏血酸盐膜的物理化学性质和抗氧化活性进行了表征，并以壳聚糖醋酸盐膜作为对照进行了比较。结果表明，壳聚糖与抗坏血酸的酯化不仅提高了壳聚糖基膜的总色差、色饱和度、不透明度、阻隔紫外可见光的能力和水溶性，而且与壳聚糖醋酸盐膜相比，降低了膜的含水量、溶胀度和水蒸气透过率。此外，正如预期的那样，抗氧化活性测定表明，抗坏血酸掺入壳聚糖基质中可有效增强对 DPPH 自由基的清除活性和还原能力。CsVc 和 CsVc 对 DPPH 自由基的清除能力最强（EC < 0.025 mg/mL）。这些发现表明，所制备的壳聚糖抗坏血酸盐膜可用作食品包装工业中新型的绿色抗氧化材料。
