壳聚糖没食子酸衍生物制备及其对鲜切苹果的保鲜作用

Preparation of Chitosan Gallic Acid Derivatives and Its Effect on Preservation of Fresh-cut Apple 2 (1.) (2.) Abstract: Key words:

摘要:

为拓宽壳聚糖在鲜切果蔬保鲜方面的应用，该文针对鲜切果蔬腐败特点以及壳聚糖（CTS）和没食子酸（GA）的结构特征，制备出一种新的壳聚糖没食子酸衍生物（CTS-GA），并对其鲜切苹果保鲜效果进行了研究。通过紫外光谱、红外光谱、X射线衍射和HPLC等检测手段对衍生物进行了初步表征，表明新生成的壳聚糖没食子酸衍生物是由没食子酸的羧基与壳聚糖分子上的氨基和羟基反应连接而成。研究了不同处理鲜切苹果在4 ℃贮藏4 d期间Vc含量、多酚含量、多酚氧化酶（PPO）活性和微生物总数的变化，结果表明贮藏第4 d时，CTS-GA处理组的多酚含量为1.29±0.067 mg/g，显著高于空白处理；Vc含量为(1.36±0.03)?10-2 mg/g，均显著高于空白、CTS处理和GA处理；PPO活性为141.78±4.31 U/g md，显著低于空白和CTS处理；微生物总数大约在5.406±0.012 (lg CFU/g)，显著低于CTS、GA浸泡处理组以及空白对照组的微生物数量。

Abstract:

According to the spoilage characteristics of the fresh-cut fruits and vegetables as well as structural features of chitosan (CTS) and gallic acid (GA), a kind of water-soluble CTS-GA was prepared by conjugating GA onto CTS and the effect of CTS-GA on preservation quality of fresh-cut apples was studied. The preliminary characterization of derivatives was studied through a series of testing methods, such as UV spectrum, FTIR spectrum, X-ray diffraction and HPLC, which shown that CTS-GA was formed by connecting amine groups from GA and hydroxyl groups from CTS. Some biochemical changes of fresh-cut apples coated with CTS, GA and CTS-GA were investigated. The results showed that after 4 d storage, polyphenols content of CTS-GA group was 1.29 ± 0.067 mg/g, which was significant higher than that of the blank group. Vc content of CTS-GA group was (1.36±0.03)?10-2 mg/g, higher than those of blank, CTS group and GA group, while PPO activity by CTS-GA treatment was 141.78 ± 4.31 U/g md, lower than the blank and CTS treatments. And the amount of microorganism in CTS-GA group was 5.406 ± 0.012 (lg CFU/g), obviously lower than the blank, CTS group and GA group.