Zhang Xiao, Wu Hao, Zhang Linan, Sun Qingjie
College of Food Science and Engineering, Qingdao Agricultural University Qingdao 266109 Shandong People's Republic of China
Marine Science and Engineering College, Qingdao Agricultural University Qingdao 266109 Shandong People's Republic of China
RSC Adv. 2018 Jun 4;8(36):20363-20371. doi: 10.1039/c8ra02632g. eCollection 2018 May 30.
Owing to their good solubility and film-forming properties, phenolic acid--chitosan derivatives can be used for preservation of fruits and vegetables. However, the chemical synthesis used for the preparation of these derivatives poses a great challenge to food safety. In this study, a method involving horseradish peroxidase catalysis was used to prepare a gallic acid--chitosan derivative. The grafting mechanism was studied. Then, the derivative's ability to scavenge free radicals and its preserving application in cherry tomatoes were evaluated. The results indicated that the reaction for horseradish peroxidase catalysis occurred between the amino group of chitosan and the carboxyl group of gallic acid. After enzymatic grafting, the gallic acid--chitosan derivative possessed excellent antioxidant abilities in scavenging DPPH, hydroxyl, and superoxide anion radicals. When the derivative was used for the preservation of cherry tomatoes, the results showed that it could effectively protect the ascorbate-glutathione cycle and antioxidant enzyme system of cherry tomatoes and inhibit enzymatic browning. In addition, since this derivative delayed the postharvest senescence of cherry tomatoes, the aroma compounds remain relatively constant throughout the storage period.
由于具有良好的溶解性和成膜性能，酚酸-壳聚糖衍生物可用于果蔬保鲜。然而，用于制备这些衍生物的化学合成方法对食品安全构成了巨大挑战。在本研究中，采用辣根过氧化物酶催化法制备了没食子酸-壳聚糖衍生物。研究了接枝机理。然后，评估了该衍生物清除自由基的能力及其在樱桃番茄保鲜中的应用。结果表明，辣根过氧化物酶催化反应发生在壳聚糖的氨基和没食子酸的羧基之间。酶促接枝后，没食子酸-壳聚糖衍生物在清除DPPH、羟基和超氧阴离子自由基方面具有优异的抗氧化能力。当该衍生物用于樱桃番茄保鲜时，结果表明它能有效保护樱桃番茄的抗坏血酸-谷胱甘肽循环和抗氧化酶系统，并抑制酶促褐变。此外，由于该衍生物延缓了樱桃番茄的采后衰老，在整个贮藏期内香气化合物保持相对稳定。
