Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
Department of Food Science, Cornell University, Ithaca, NY 14853, USA; New York State Agricultural Experiment Station, Geneva, NY 14456, USA.
Food Chem. 2015 May 1;174:310-8. doi: 10.1016/j.foodchem.2014.11.015. Epub 2014 Nov 8.
Analysis of food volatiles generated by processing are widely reported but comparisons across studies is challenging in part because most reports are inherently semi-quantitative for most analytes due to limited availability of chemical standards. We recently introduced a novel strategy for creation of broad spectrum isotopic standards for accurate quantitative food chemical analysis. Here we apply the principle to quantification of 25 volatiles in seven thermally oxidised edible oils. After extended oxidation, total volatiles of high n-3 oils (flax, fish, cod liver) were 120-170 mg/kg while low n-3 vegetable oils were <50mg/kg. Separate experiments on thermal degradation of d5-ethyl linolenate indicate that off-aroma volatiles originate throughout the n-3 molecule and not solely the n-3 terminal end. These data represent the first report using broad-spectrum isotopically labelled standards for quantitative characterisation of processing-induced volatile generation across related foodstuffs, and verify the origin of specific volatiles from parent n-3 fatty acids.
加工产生的食物挥发物分析得到了广泛的报道，但由于化学标准品的有限可用性，大多数分析物的报告本质上是半定量的，因此跨研究的比较具有挑战性。我们最近引入了一种新的策略，用于为准确的定量食物化学分析创建广谱同位素标准品。在这里，我们将该原理应用于七种热氧化食用油中 25 种挥发物的定量。经过长时间氧化，高 n-3 油（亚麻、鱼、鱼肝油）的总挥发物含量为 120-170mg/kg，而低 n-3 植物油的含量则低于 50mg/kg。关于 d5-亚乙基亚麻酸热降解的单独实验表明，异味挥发物源自整个 n-3 分子，而不仅仅是 n-3 末端。这些数据代表了使用广谱同位素标记标准品对相关食品加工诱导挥发物生成进行定量表征的首次报告，并验证了特定挥发物源自母体 n-3 脂肪酸。
