维生素C磷酸酯镁的稳定性及其清除超氧离子自由基的动力学

维生素C磷酸酯镁(magnesium ascorbyl phosphate,MAP)是维生素C(VC)的替代品,由于其特有的性质而广泛应用在食品添加剂中.对比测定了MAP和VC清除超氧阴离子自由基(O2-·)的能力,研究了VC和MAP在不同温度和不同保存时间后清除O2-·自由基的能力和稳定性;并拟合了不同温度下储存不同时间后MAP的抗氧化能力.结果表明,MAP在20℃下保存20d对O2-·的清除能力仅减弱20%左右,半衰期为53d;但VC在20℃下保存10d后清除O2-·的能力几乎完全消失.与此同时,不同温度下储存不同时间后MAP清除超氧阴离子自由基的反应为一级反应,采用拟合方程计算的抗氧化能力理论值和实验值基本相符.

Stability of magnesium ascorbyl phosphate of vitamin C and its dynamics of scavenging superoxide anion radical

Thanks to its peculiar properties, magnesium ascorbyl phosphate （MAP） as a substi- tute of vitamin C （Vc） is widely used as food additive. This research compares the ability of MAP and Vc to scavenge superoxide anion radical （O2-· ）. Their ability to scavenge O2-· and their thermal stability were investigated in relation to storage at different temperature for dif- ferent duration. Furthermore, their anti-oxidation ability was also examined in relation to stor- age at different temperature for different duration. Results show that the ability of MAP to scavenge O2-· is reduced by only about 20% after it is stored at 20 ℃ for 20 d, and in this case its half-life is 53 d. However, after being stored at 20℃ for 10 d, Vc nearly completely loses ability to scavenge O2-·. In the meantime, the reaction for MAP stored at different tempera- ture for different duration to scavenge O2-· can be described with a first order dynamics equa- tion, and its anti oxidation ability calculated based on the simulated equation well conforms to the experimental one.