In this study, carboxymethyl chitosan (CMCS) was combined with epigallocatechin gallate (EGCG), a natural antioxidant polyphenol, by a free radical grafting procedure to enhance its application potential on the preservation of fruit juice. The successful formation of EGCG-grafted CMCS (EGCG-CMCS) was confirmed by ultraviolet–visible absorbance, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance. The optimal molar ratio of EGCG to CMCS monomer was 0.5:1, which led to a grafting ratio of 47.8 mg/g in EGCG-CMCS. The X-ray diffraction patterns and thermal behavior showed that EGCG-CMCS had a lower crystallinity and thermal stability than CMCS, which is probably due to the reduction in hydrogen bonds caused by grafting. Then, EGCG-CMCS was used as an additive for the preservation of grape juice. After storage at 4 °C for 7 days, the EGCG-CMCS–treated juice remained 90.6% of vitamin C, which was much higher than that of the CMCS-treated juice and the control. Similar results were also achieved for total phenolic content, total soluble solids, and titratable acidity. Moreover, EGCG-CMCS effectively maintained the antioxidant capacity and sensory color quality of the juice and inhibited microbial growth during storage. Our results suggest that ECGC-CMCS could be a promising biopreservative for fresh fruit juice.

在这项研究中，羧甲基壳聚糖（CMCS）与天然抗氧化剂多酚表没食子儿茶素没食子酸酯（EGCG）结合使用，通过自由基接枝程序增强了其在果汁保存中的应用潜力。紫外可见吸收，傅立叶变换红外光谱和质子核磁共振证实了EGCG接枝CMCS（EGCG-CMCS）的成功形成。EGCG与CMCS单体的最佳摩尔比为0.5：1，因此在EGCG-CMCS中的接枝率为47.8 mg / g。X射线衍射图和热行为表明，EGCG-CMCS具有比CMCS低的结晶度和热稳定性，这可能是由于接枝引起的氢键减少。然后，EGCG-CMCS被用作葡萄汁保存的添加剂。在4°C下储存7天后，EGCG-CMCS处理过的果汁保留了90.6％的维生素C，远高于CMCS处理过的果汁和对照。总酚含量，总可溶性固形物和可滴定酸度也获得了相似的结果。此外，EGCG-CMCS有效地保持了果汁的抗氧化能力和感官色彩质量，并在储存过程中抑制了微生物的生长。我们的结果表明ECGC-CMCS可能是新鲜果汁的有前途的生物防腐剂。EGCG-CMCS有效地保持了果汁的抗氧化能力和感官色彩质量，并在储存过程中抑制了微生物的生长。我们的结果表明ECGC-CMCS可能是新鲜果汁的有前途的生物防腐剂。EGCG-CMCS有效地保持了果汁的抗氧化能力和感官色彩质量，并在储存过程中抑制了微生物的生长。我们的结果表明ECGC-CMCS可能是新鲜果汁的有前途的生物防腐剂。