Department of Viticulture and Enology, University of California, Davis, Davis, CA, United States; Food Safety and Measurement Facility, University of California, Davis, Davis, CA, United States.
Agilent Technologies, Inc., Santa Clara, CA, United States.
Food Chem. 2019 Nov 1;297:124921. doi: 10.1016/j.foodchem.2019.05.195. Epub 2019 May 29.
Plants conjugate monoterpenoids to sugars, rendering them non-volatile. Hydrolysis of these glycosidic precursors frees the volatile aroma compounds. Here, we profile intact monoterpenyl glycosides in six Vitis vinifera grape berry cultivars. Relative concentrations of twenty-six monoterpenyl glycosides, including nine new putatively identified compounds, were analyzed by UHPLC-QTOF MS/MS at three times during grape maturation (pre-véraison, véraison, and post-véraison). Total glycoside content reached a maximum in Muscat cultivars post-véraison but remained relatively constant in all other cultivars. Three types of monoterpenyl glycosides predominated in all samples: malonylated monoterpenol glucosides, monoterpenol hexose-pentoses, and monoterpendiol hexose-pentoses. The two Muscat cultivars were not differentiated at the earlier developmental stages but could be differentiated post-véraison. In contrast, similarities between Chardonnay and Pinot noir glycoside profiles developed post-véraison. Overall monoterpene glycoconjugation patterns may align with underlying genetic relationships among cultivars. By understanding monoterpene glycoconjugation in wine grapes, scientists and winemakers can better understand grape and wine aromas.
植物将单萜类化合物与糖结合，使它们不易挥发。这些糖苷前体的水解释放出挥发性香气化合物。在这里，我们在六个葡萄品种的葡萄浆果中分析了完整的单萜基糖苷。通过 UHPLC-QTOF MS/MS 在葡萄成熟的三个时期（预成熟、成熟和后成熟）分析了二十六种单萜基糖苷的相对浓度，包括九种新的假定鉴定化合物。在成熟后，麝香葡萄品种的总糖苷含量达到最大值，但在所有其他品种中相对稳定。三种类型的单萜基糖苷在所有样品中占主导地位：单萜醇葡萄糖醛酸酯、单萜醇己糖-戊糖和单萜二醇己糖-戊糖。在早期发育阶段，两个麝香葡萄品种没有区别，但在成熟后可以区分。相比之下，霞多丽和黑比诺葡萄的糖苷图谱在成熟后相似。总的来说，单萜糖缀合物的模式可能与品种之间的遗传关系一致。通过了解葡萄酒葡萄中单萜糖缀合，科学家和酿酒师可以更好地了解葡萄和葡萄酒的香气。
