摘要
以工业碱木质素为原料,采用购买和自制两种钯/炭(Pd/C)为催化剂,氢气为还原剂,在高压条件下对其进行还原反应,提高碱木质素的活性,并对其反应前后化学成分和抗氧化性能进行分析。结果表明:经过两种催化剂高压催化活化后,购买催化剂还原碱木质素醇羟基含量为5.01%,酚羟基含量为3.64%。自制催化剂还原碱木质素醇羟基含量为5.35%,酚羟基含量为3.82%。自制Pd/C催化剂催化体系的催化效果优于购买Pd/C催化剂;在抗氧化性能分析实验中,碱木质素原料及两种被还原碱木质素在质量浓度范围为0.025～0.6mg/mL内对DPPH自由基和.OH均有较强的清除能力,且随着木质素质量浓度的增加,清除率逐渐增加,还原力也增强,两种被还原碱木质素DPPH自由基最大清除率分别达到80.91%和82.43%;.OH最大清除率分别达到23.12%和26.21%。
In this study, commercial and laboratory-prepared Pd/carbon catalysts were used for the reduction of industrial alkali lignin by hydrogen under high pressure conditions in order to increase lignin activity. The chemical composition and antioxidant activity of alkali lignin and its reduced products were analyzed. The contents of alcohol hydroxyl groups and phenolic hydroxyl groups in commercial Pd/carbon activated alkali lignin were 5.01% and 3.64%, respectively, compared to 5.35% and 3.82% for laboratory-prepared Pd/carbon activated alkali lignin. Thus, the laboratory-prepared Pd/carbon has better catalysis performance than the commercial Pd/carbon. Both alkali lignin and its reduced products had strong radical scavenging activity against DPPH and hydroxyl radicals at a concentration ranging from 0.025 to 0.6 mg/mL in a concentration-dependent manner. The maximum scavenging rates of commercial Pd/carhon activated alkali lignin and laboratory-prepared Pd/carbon activated alkali lignin were 80.91% and 82.43% for DPPH free radical and 23.12% and 26.21% for hydroxyl free radical, respectively.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2013年第7期6-10,共5页
Food Science
基金
国家自然科学基金项目(31170542)
国家公益性行业(林业)科研专项(200904072)
关键词
钯
炭催化剂
碱木质素
抗氧化性能
还原
自由基
palladium/carboncatalyst
lignin
antioxidativeproperty
reduction
free radical
