利用碱-H2O2法从玉米麸皮中提取出阿拉伯木聚糖（CAX），将咖啡酸（CA）通过酯键连接到CAX上得到阿拉伯木聚糖咖啡酸酯（CA-CAX），用红外，核磁氢谱、碳谱确定了结构，用高效液相色谱确定了CA的取代度，调整CA用量，得到不同取代度的CA-CAX-s（s表示取代度），并用高效凝胶渗透色谱测定不同取代度的分子量，CAX、CA-CAX-0.27、CA-CAX-0.51和CA-CAX-0.65的重均分子量分别为3.07×105、3.09×105、3.36×105和3.68×105 g/mol。通过紫外检测表明，CA-CAX-s在UVB具有较高的紫外吸收，而且CA-CAX-s水溶液的黏度明显增大，紫外吸收及黏度的大小均随CA含量的增加而增大。CA-CAX-0.27、CA-CAX-0.51和CA-CAX-0.65清除DPPH自由基的IC50分别为0.28、0.13和0.12 mg/mL。脂质过氧化物的检测CA-CAX-0.65用量为4 mg/mL时可以将丙二醛（MDA）的含量从120 ng/mL降低到最低值51.80 ng/mL。抗氧化能力指数（ORAC）测定结果表明改性后CA-CAX-s可将荧光消失的时间从13 min延长至60 min以上，ORAC值也从7上升至62.83。CA-CAX的抗氧化性较CAX有明显提高，而且咖啡酸含量越高CA-CAX-s的抗氧化性越好。

Arabinoxylan (CAX) was extracted from corn bran by the alkali-H2O2 method, and then caffeic acid (CA) was connected to CAX through ester bonding to yield caffeic acid arabinoxylanesters (CA-CAX). The structure of CA-CAX was characterized by FT-IR and H- and C-NMR, and its degree of substitution (DS) was determined by HPLC.CA-CAXs with different DSs (s represents degree of substitution) were obtained through using different amounts of CA, and their molecular weights were determined by high performance gel permeation chromatography(3.09×105, 3.36×105 and 3.68×105 g/mol for CAX, CA-CAX-0.27, CA-CAX-0.51 and CA-CAX-0.65, respectively). UV detection showed that CA-CAX-s had higher UVB absorption, and its aqueous solution exhibited significantly increased viscosity. Both the UV absorption and viscosity increased with an increase of CA content. In terms of DPPH free radical scavenging activity, the IC50 values of CA-CAX-0.27, CA-CAX-0.51 and CA-CAX-0.65 were 0.28, 0.13 and 0.12 mg/mL, respectively. Lipid peroxide detection of CA-CAX-0.65 at 4 mg/mL could reduce the content of malondialdehyde (MDA) from 120 ng/mL to the lowest value of 51.80 ng/mL. The analysis of antioxidant capacity index (ORAC) showed that the modified CA-CAX-s could delay the disappearance of fluorescence from 13 min to over 60 min, and also increased the ORAC value from 7 to 62.83.The antioxidant activity of CA-CAX was significantly higher than that of CAX, and a higher CA content led to a higher antioxidant activity of CA-CAX-s.

四川省科技厅重点研发项目（2019YFG0174）；四川轻化工大学人才引进项目（2018RCL02）