Fonseca Daniela, Martins Nuno, Garcia Raquel, Cabrita Maria João
Mediterranean Institute for Agriculture, Environment and Development & Institute of Research and Advanced Training, University of Évora, Pólo da Mitra, Ap. 94, 7006-554 Évora, Portugal.
Mediterranean Institute for Agriculture, Environment and Development & Global Change and Sustainability Institute, University of Évora, Pólo da Mitra, Ap. 94, 7006-554 Évora, Portugal.
Molecules. 2024 Apr 26;29(9):1989. doi: 10.3390/molecules29091989.
Varietal volatile compounds are characteristic of each variety of grapes and come from the skins of the grapes. This work focuses on the development of a methodology for the analysis of free compounds in grapes from Trincadeira, Cabernet Sauvignon, Syrah, Castelão and Tinta Barroca from the 2021 and 2022 harvests, using HS-SPME-GC × GC-TOFMS. To achieve this purpose, a previous optimization step of sample preparation was implemented, with the optimized conditions being 4 g of grapes, 2 g of NaCl, and 2 mL of HO. The extraction conditions were also optimized, and it was observed that performing the extraction for 40 min at 60 °C was the best for identifying more varietal compounds. The fiber used was a triple fiber of carboxen/divinylbenzene/polydimethylsiloxane (CAR/DVB/PDMS). In addition to the sample preparation, the analytical conditions were also optimized, enabling the adequate separation of analytes. Using the optimized methodology, it was possible to identify fifty-two free volatile compounds, including seventeen monoterpenes, twenty-eight sesquiterpenes, and seven C-norisoprenoids. It was observed that in 2021, more free varietal volatile compounds were identifiable compared to 2022. According to the results obtained through a linear discriminant analysis (LDA), the differences in volatile varietal signature are observed both among different grape varieties and across different years.
品种挥发性化合物是每个葡萄品种的特征,来源于葡萄皮。这项工作的重点是开发一种方法,用于分析2021年和2022年收获季的特林卡岱拉、赤霞珠、西拉、卡斯特劳和丹魄罗卡葡萄中的游离化合物,采用顶空固相微萃取-全二维气相色谱-飞行时间质谱法(HS-SPME-GC×GC-TOFMS)。为实现这一目的,实施了样品制备的前期优化步骤,优化条件为4克葡萄、2克氯化钠和2毫升水。萃取条件也进行了优化,结果发现,在60℃下萃取40分钟最有利于鉴定更多的品种化合物。使用的纤维是碳分子筛/二乙烯基苯/聚二甲基硅氧烷(CAR/DVB/PDMS)三重纤维。除了样品制备外,分析条件也进行了优化,从而能够对分析物进行充分分离。使用优化后的方法,可以鉴定出52种游离挥发性化合物,包括17种单萜、28种倍半萜和7种C-降异戊二烯类化合物。结果发现,与2022年相比,2021年可鉴定出更多的游离品种挥发性化合物。根据通过线性判别分析(LDA)获得的结果,在不同葡萄品种之间以及不同年份之间均观察到挥发性品种特征的差异。