Christy Alfred A, Xu Zhanfeng, Harrington Peter de B
Department of Chemistry, Faculty of Engineering and Science, University of Agder, Serviceboks 422, N-4604 Kristiansand, Norway.
Chem Phys Lipids. 2009 Mar;158(1):22-31. doi: 10.1016/j.chemphyslip.2008.12.002. Epub 2008 Dec 24.
Triolein, a triglyceride containing oleic acid as the only acid moiety in the glyceride molecules has been isothermally treated at 280, 300, and 325 degrees C in glass vials under nitrogen atmosphere. The products formed during the thermal treatment at each temperature have been analysed both by infrared spectrometry and GC-MS. The GC-MS analysis was performed after derivatisation of the fatty acids into their methyl esters (FAMEs). Chemometric tools were used in determining the concentrations of the main products namely triolein and trieaidin in the thermally treated mixtures. The concentration profiles of the trielaidin formed during thermal treatment at the above three temperatures were used in determining activation energy for the cis-trans isomerisation of triolein. The combined analysis reveals that the thermal treatment induces not only cis-trans isomerisation but also fission and fusion in the molecules. Furthermore, migration of the double bond in oleic and elaidic acids forming cis and trans isomers of the 18:1 acid was also observed. The heat-induced isomerisation in triolein follows a zeroth order reaction with an activation energy 41+/-5 kcal/mol.
三油酸甘油酯是一种甘油酯分子中仅含油酸作为唯一酸部分的甘油三酯，已在氮气气氛下于玻璃小瓶中分别在280、300和325摄氏度进行等温处理。每个温度下热处理过程中形成的产物均通过红外光谱法和气相色谱 - 质谱联用仪（GC-MS）进行了分析。GC-MS分析是在将脂肪酸衍生化为其甲酯（FAMEs）后进行的。化学计量工具用于测定热处理混合物中主要产物即三油酸甘油酯和三反油酸甘油酯的浓度。利用上述三个温度下热处理过程中形成的三反油酸甘油酯的浓度分布来确定三油酸甘油酯顺反异构化的活化能。综合分析表明，热处理不仅会引起顺反异构化，还会导致分子的裂变和融合。此外，还观察到油酸和反油酸中双键的迁移，形成了18:1酸的顺式和反式异构体。三油酸甘油酯中的热诱导异构化遵循零级反应，活化能为41±5千卡/摩尔。
