School of Liquor and Food Engineering, Guizhou University, Guiyang 550025, P. R. China.
School of Liquor and Food Engineering, Guizhou University, Guiyang 550025, P. R. China..
Food Res Int. 2022 Jul;157:111295. doi: 10.1016/j.foodres.2022.111295. Epub 2022 Apr 25.
In this study, the radicals formed in camellia oil upon a heating process were identified and quantified using Electron Spin Resonance (ESR) spectroscopy coupled with spin-trapping technique. PBN and DMPO were served as spin traps. The total amounts of free radicals of heated camellia oil showed an increasing trend with the extension of heating time at 140 °C, 150 °C and 160 °C. In accordance with hyperfine splitting constants (aN, aH) ─ the crucial parameter for identifying free radical species ─ of free radical, it was definitely confirmed that alkyl, alkoxyl, oxygen-centered and DMPO oxidate free radicals were present in heated camellia oil. A free radical transition pathway was proposed that alkyl free radical is initially generated, then, alkyl peroxy free radical is subsequently generated in the presence of oxygen which eventually shifts into alkoxyl free radical by means of an intermediate formed from H-capture reaction of alkyl peroxy free radical.
在这项研究中，采用电子自旋共振（ESR）光谱结合自旋捕获技术，鉴定和定量了加热过程中茶籽油中形成的自由基。PBN 和 DMPO 用作自旋捕获剂。在 140°C、150°C 和 160°C 的加热时间延长的情况下，加热茶籽油的自由基总量呈上升趋势。根据自由基的超精细分裂常数（aN、aH）─确定自由基种类的关键参数─，可以确定在加热的茶籽油中存在烷基、烷氧基、氧中心和 DMPO 氧化自由基。提出了一个自由基转化途径，即在存在氧的情况下，首先生成烷基自由基，然后生成烷基过氧自由基，最终通过烷基过氧自由基的 H 捕获反应形成的中间体转化为烷氧基自由基。
