三孢布拉霉产β-胡萝卜素的抗氧化活性动力学研究

摘要

β-carotene was an important natural antioxidant. The Blakeslea trispora was receiving increasing attention since its higher industrial production of carotenoids.The scavenging free radical ability of β-carotene from Blakeslea trispora was evaluated by DPPH method to study the antioxidant activity with different concentrations at different temperatures.What's more,the related kinetic data,such as EC50,Ea,and k were calculated.The results showed that the equilibrium time of antioxidant activity of β-carotene at 37℃was 30 min,which was shorter than it at 25℃at the same concentration.The higher the temperature is,the faster the reaction speed. And the antioxidant activity increased with increasing concentration at the same temperature. When the concentration was 160 μg/mL, removal efficiency can reach 70.77 %. In addition, the reaction temperature had a great influence on the antioxidant activity.With the increasing of reaction temperature,the reaction rate constant k increasesd by calculation.But the initial concentration had no effect on the activity.The Ea was not signi cantly in uenced by different concentrations,which was about 31 kJ/mol.%β-胡萝卜素具有较强的抗氧化活性,三孢布拉霉(Blakeslea trispora)是β-胡萝卜素的高产菌株.以发酵三孢布拉霉菌株提取的 β-胡萝卜素为研究对象,采用 DPPH(对1,1-二苯基-2-三硝基苯肼,1,1-diphenyl-2-picrylhydrazyl)法,测定自由基清除率,对β-胡萝卜素抗氧化活性进行研究.考察在不同温度下,不同浓度的β-胡萝卜素抗氧化活性的不同,计算了相关动力学数据:活性半数效应浓度(EC50)、表观活化能(Ea)和反应速率常数(k).结果表明,相同浓度下,β-胡萝卜素在37℃抗氧化活性达到平衡的时间为30 min,短于25℃时45 min的平衡时间,说明温度越高,反应速度越快;在相同温度下,β-胡萝卜素浓度越高,抗氧化活性越强,当浓度达到160 μg/mL时,达到70.77 %的清除效率.同时,通过计算可得,随反应温度的升高,反应速率常数k增大,说明反应温度对β-胡萝卜素抗氧化活性有较大影响,但不同质量浓度的Ea稳定在31 kJ/mol左右,没有显著性差异,说明起始浓度对活性没有影响.