Dipartimento di Scienze degli Alimenti, Università degli Studi di Parma, Parco Area delle Scienze 95/A, I-43124 Parma, Italy.
J Sci Food Agric. 2013 Sep;93(12):2909-16. doi: 10.1002/jsfa.6168. Epub 2013 May 9.
The nature of the relationship between differential scanning calorimetry thermal properties and the oxidation and hydrolysis compounds formed during a real auto-oxidation process in virgin olive oils has not been evaluated so far, as these samples are difficult to find. In this work, 21 samples of virgin olive oil, stored under ideal conditions since their years of production (production range 1991-2005) to develop the natural auto-oxidation process, were analysed in order to evaluate this relationship.
Oils stored the longest time showed the highest hydrolytic degradation while the others exhibited higher contents of oxidised fatty acids and triacylglycerols, instead. Thermal properties of transitions were differently influenced by degradation compounds with the onset of both the cooling and heating profiles particularly influenced by diacylglycerols and oxidised lipids. Chemical data and thermal properties were correlated by using principal component analysis. Twenty-three variables were selected for the analysis with the first component fully segregating samples into two groups according to the year of storage and the level of hydrolysis and/or oxidation, on the basis of selected thermal properties obtained by cooling and heating transitions.
These preliminary findings showed that differential scanning calorimetry could be considered an useful tool to evaluate lipid degradation in virgin olive oils, indicating its value as a support to chemical techniques.
到目前为止，尚未评估差示扫描量热法（DSC）热特性与在 virgin olive oil 实际自动氧化过程中形成的氧化和水解化合物之间的关系，因为这些样品很难找到。在这项工作中，分析了 21 个 virgin olive oil 样品，这些样品自生产年份（1991-2005 年）以来一直储存在理想的条件下，以发展自然自动氧化过程，以评估这种关系。
储存时间最长的油显示出最高的水解降解，而其他油则显示出更高的氧化脂肪酸和三酰基甘油含量。转变的热特性受到降解化合物的不同影响，冷却和加热曲线的起始都受到二酰基甘油和氧化脂质的特别影响。通过主成分分析对化学数据和热特性进行了相关性分析。选择了 23 个变量进行分析，第一个成分根据储存时间和水解和/或氧化水平，将样品完全分为两组，基于冷却和加热转变获得的选定热特性。
这些初步发现表明，差示扫描量热法可被视为评估 virgin olive oil 中脂质降解的有用工具，表明其作为化学技术支持的价值。
