玉米麸质阿拉伯木聚糖对香豆酸酯的制备及性能研究

摘要

通过对水溶性玉米麸质阿拉伯木聚糖(CAX)进行改性,使CAX具有抗氧化性.将CAX溶解到DMA/LiCl体系中,以三乙胺为缚酸剂,与对香豆酸酰氯进行酯化反应得到阿拉伯木聚糖对香豆酸酯(p-CA-CAX).用红外、核磁对其结构进行了鉴定,表明对香豆酸(p-CA)以酯键的形式连接在CAX上.用高效液相色谱确定了p-CA的取代度,p-CA与CAX的糖苷键的摩尔比分别为1∶5,1∶4,1∶3,1∶2和1∶1时,取代度分别为0.38,0.51,0.63,0.83和0.94.用凝胶渗透色谱确定了不同取代度的p-CA-CAX的分子量,p-CA-CAX-0.38,p-CA-CAX-0.51和p-CA-CAX-0.63的分子量分别为3.52×105,3.85×105和3.93×105.脂质过氧化物的检测和抗氧化能力指数(ORAC)的测定表明,p-CA-CAX具有较好的抗氧化性,而且p-CA含量越高,p-CA-CAX的抗氧化性越好.%By modifying water-soluble corn gluten arabinoxylan (CAX) to make CAX antioxidant.CAX was dissolved in DMA/LiCl system,took triethylamine as an acid binding agent,esterification with coumaryl chloride of this solution was realized,and arabinoxylan p-coumarate (p-CA-CAX) was obtained.The structure was analyzed by IR and NMR.Results show that p-coumaric acid (p-CA) is connected to CAX in the form of ester bond.High performance liquid chromatography (HPLC) was used to confirm the degree of substitution (DS) of p-CA.When the molar ratio of p-CA and glucoside bonds of CAX is 1∶ 5,1 ∶ 4,1∶ 3,1∶ 2 and 1∶ 1,respectively,the DS is 0.38,0.51,0.63 0.83 and 0.94,correspondingly.The molecular weights of p-CA-CAX of different DS were determined by gel permeation chromatography.The molecular weights of p-CA-CAX-0.38,p-CA-CAX-0.51 and p-CA-CAX-0.63 are 3.52 × 105,3.85 × 105 and 3.93 × 105,respectively.Determination of lipid peroxides and oxygen radical absorbance capacity (ORAC) shows that p-CA-CAX has good antioxidant activity and the higher the content of p-CA,the better the antioxidant activity of p-CA-CAX.