Laboratory for Aroma Analysis and Enology, Aragón Institute of Engineering Research (I3A), Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, 50009 Zaragoza, Spain.
Food Chem. 2013 Nov 1;141(1):105-10. doi: 10.1016/j.foodchem.2013.03.027. Epub 2013 Mar 16.
The Tuber indicum (Chinese truffle) and Tuber melanosporum (Black truffle) species are morphologically very similar but their aromas are very different. The black truffle aroma is much more intense and complex, and it is consequently appreciated more gastronomically. This work tries to determine whether the differences between the aromatic compounds of both species are sufficiently significant so as to apply them to fraud detection. An olfactometric evaluation (GC-O) of T. indicum was carried out for the first time. Eight important odorants were identified. In order of aromatic significance, these were: 1-octen-3-one and 1-octen-3-ol, followed by two ethyl esters (ethyl isobutyrate and ethyl 2-methylbutyrate), 3-methyl-1-butanol, isopropyl acetate, and finally the two sulfides dimethyldisulfide (DMDS) and dimethylsulfide (DMS). A comparison of this aromatic profile with that of T. melanosporum revealed the following differences: T. indicum stood out for the significant aromatic contribution of 1-octen-3-one and 1-octen-3-ol (with modified frequencies (MF%) of 82% and 69%, respectively), while in the case of T. melanosporum both had modified frequencies of less than 30%. Ethyl isobutyrate, ethyl 2-methylbutyrate and isopropyl acetate were also significantly higher, while DMS and DMDS had low MF (30-40%) compared to T. melanosporum (>70%). The volatile profiles of both species were also studied by means of headspace solid-phase microextraction (HS-SPME-GC-MS). This showed that the family of C8 compounds (3-octanone, octanal, 1-octen-3-one, 3-octanol and 1-octen-3-ol) is present in T. indicum at much higher levels. The presence of 1-octen-3-ol was higher by a factor of about 100, while 1-octen-3-one was detected in T. indicum only (there was no chromatographic signal in T. melanosporum). As well as showing the greatest chromatographic differences, these two compounds were also the most powerful from the aromatic viewpoint in the T. indicum olfactometry. Therefore, either of the two chromatographic methods (GC-O or HS-SPME-GC-MS), together or separately, could be used as a screening technique to distinguish between T. indicum and T. melanosporum and thus avoid possible fraud.
块菌（中国块菌）和黑块菌（黑块菌）在形态上非常相似，但它们的香气却大不相同。黑块菌的香气更加浓郁复杂，因此在美食方面更受欢迎。本研究旨在确定这两个物种的芳香化合物之间的差异是否足够显著，以便将其应用于欺诈检测。首次对块菌进行了嗅觉评估（GC-O）。鉴定出了 8 种重要的气味物质。按香气重要性排列，它们分别为：1-辛烯-3-酮和 1-辛烯-3-醇，其次是两种乙酯（异丁酸乙酯和 2-甲基丁酸乙酯），3-甲基-1-丁醇，乙酸异丙酯，最后是两种硫化合物二甲基二硫（DMDS）和二甲基硫（DMS）。将这种芳香特征与黑块菌进行比较，结果表明：块菌的 1-辛烯-3-酮和 1-辛烯-3-醇的香气贡献非常显著（修饰频率（MF%）分别为 82%和 69%），而黑块菌的修饰频率均低于 30%。异丁酸乙酯、2-甲基丁酸乙酯和乙酸异丙酯的含量也明显较高，而 DMS 和 DMDS 的 MF 与黑块菌相比（>70%）较低（30-40%）。通过顶空固相微萃取（HS-SPME-GC-MS）也研究了这两个物种的挥发性特征。结果表明，C8 化合物家族（3-辛酮、辛醛、1-辛烯-3-酮、3-辛醇和 1-辛烯-3-醇）在块菌中的含量要高得多。1-辛烯-3-醇的含量高出约 100 倍，而 1-辛烯-3-酮仅在块菌中检测到（黑块菌中没有色谱信号）。这两种化合物不仅在色谱上差异最大，而且在块菌嗅觉分析中也是最具香气的化合物。因此，这两种色谱方法（GC-O 或 HS-SPME-GC-MS），无论是单独使用还是一起使用，都可以作为一种筛选技术，将块菌和黑块菌区分开来，从而避免可能的欺诈。
