Université de Lorraine, LIBio, F-54000 Nancy, France.
Université de Lorraine, CNRS, CRM2, F-54000 Nancy, France.
Int J Biol Macromol. 2021 Feb 1;169:480-491. doi: 10.1016/j.ijbiomac.2020.12.113. Epub 2020 Dec 19.
The modification of gum Arabic with ferulic acid oxidation products was performed in aqueous medium, at 30 °C and pH 7.5, in the presence of Myceliophthora thermophila laccase as biocatalyst. First, this study aimed to investigate the structures of the oxidation products of ferulic acid that could possibly be covalently grafted onto gum Arabic. HPLC analyses revealed that this reaction produced several oxidation products, whose structures were investigated using LC-MS/MS analyses (liquid chromatography-mass spectrometry with mass fragmentation analyses) and NMR experiments. The chemical structure of one intermediate reaction product was fully elucidated as the 2-(4-hydroxy-3-methoxyphenyl)-4-[(4-hydroxy-3-methoxyphenyl) methylidene] cyclobutane-1, 3-dione, called by the authors cyclobutadiferulone. Secondly, this study aimed to locate the grafting of the oxidation products onto gum Arabic by performing several NMR experiments. This study did not determine how much and specifically which oxidation products were grafted but some of them were undeniably present onto modified gum Arabic, close to the glucuronic acid C5 carbon or close to the galactose C6 carbon.
用阿魏酸氧化产物对阿拉伯胶进行修饰是在水介质中、30°C 和 pH7.5 条件下、在嗜热毁丝霉漆酶作为生物催化剂的存在下进行的。首先，本研究旨在研究可能共价接枝到阿拉伯胶上的阿魏酸氧化产物的结构。HPLC 分析表明，该反应产生了几种氧化产物，其结构通过 LC-MS/MS 分析（带质谱碎裂分析的液相色谱-质谱联用）和 NMR 实验进行了研究。一个中间反应产物的化学结构被完全阐明为 2-(4-羟基-3-甲氧基苯基）-4-[(4-羟基-3-甲氧基苯基）亚甲基]环丁烷-1,3-二酮，作者称之为环丁二阿魏酮。其次，本研究旨在通过进行几次 NMR 实验来确定氧化产物接枝到阿拉伯胶上的位置。本研究没有确定接枝了多少和具体哪些氧化产物，但可以肯定的是，其中一些氧化产物存在于改性的阿拉伯胶上，靠近半乳糖的 C6 碳原子或靠近葡萄糖醛酸的 C5 碳原子。
