Department of Food Chemistry, University of Wuppertal, Wuppertal, Germany.
J Agric Food Chem. 2012 Aug 8;60(31):7597-606. doi: 10.1021/jf3020574. Epub 2012 Jul 30.
Bitterness and pungency are important parameters for olive oil quality. Therefore, two instrumental methods for evaluation of these taste attributes were developed. The first one is based on the photometric measurement of total phenolic compounds content, whereas the second one is based on the semiquantitative evaluation of hydrophilic compounds by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Evaluation of total phenolic compounds content was performed by a modified method for the determination of the K(225) value using a more specific detection based on the pH value dependency of absorbance coefficients of phenols at λ = 274 nm. The latter method was not suitable for correct prediction, because no significant correlation between bitterness/pungency and total phenolic compounds content could be found. For the second method, areas of 25 peaks detected in 54 olive oil samples by a HPLC-MS profiling method were correlated with the bitterness and pungency by partial least-squares regression. Six compounds (oleuropein aglycon, ligstroside aglycon, decarboxymethyl oleuropein aglycon, decarboxymethyl ligstroside aglycon, elenolic acid, and elenolic acid methyl ester) show high correlations to bitterness and pungency. The computed model using these six compounds was able to predict bitterness and pungency of olive oil in the error margin of the sensory evaluation (±0.5) for most of the samples.
苦味和辣味是橄榄油质量的重要参数。因此，开发了两种用于评估这些味觉属性的仪器方法。第一种方法基于总酚含量的分光光度测量，而第二种方法基于高效液相色谱-质谱（HPLC-MS）对半亲水性化合物的半定量评估。总酚含量的评估通过使用更具体的检测方法，即基于在 274nm 处苯酚吸光系数对 pH 值的依赖性来测定 K(225) 值，对 K(225) 值的测定方法进行了改进。后一种方法不适合进行正确的预测，因为苦味/辣味与总酚含量之间没有明显的相关性。对于第二种方法，通过 HPLC-MS 分析方法在 54 个橄榄油样品中检测到的 25 个峰的面积通过偏最小二乘回归与苦味和辣味相关联。有 6 种化合物（橄榄苦苷配基、毛蕊花糖苷配基、去羧甲基橄榄苦苷配基、去羧甲基毛蕊花糖苷配基、齐墩果酸和齐墩果酸甲酯）与苦味和辣味高度相关。使用这 6 种化合物的计算模型能够预测大多数样品的感官评估误差范围内（±0.5）的橄榄油苦味和辣味。
