Isolation of Taste-Active Triterpenoids from Quercus robur: Sensory Assessment and Identification in Wines and Spirit

Abstract

Six new triterpenoids (1−6), two known genins (7 and 8), and five known functionalized triterpenoids (9−13) were isolated from a Quercus robur heartwood extract. The purification protocol was guided by LC-HRMS by searching for structural analogues of bartogenic acid on the basis of their putative empirical formula. The structures of the new compounds were unequivocally elucidated using HRESIMS and 1D/2D NMR experiments. Sensory analyses were performed in water and in a non-oaked white wine on the pure compounds 1−13 at 5 mg/L. All molecules were perceived as bitter in water and wine, but they were mostly reported as modifying the wine taste balance. Using LC-HRMS, compounds 1−13 were observed in oaked red wine and cognac and were semiquantified in oak wood extracts. The influence of two cooperage parameters, oak species and toasting process, on compounds 1−13 content was studied. All compounds were found in quantities significantly higher in pedunculate than in sessile oak wood. Toasting is a key step in barrel manufacture and modulates the concentration of the discussed compounds. Significantly higher quantities were observed in untoasted wood compared to medium or highly toasted wood. These findings provide new insights into the molecular origin of taste changes due to oak aging.

The Oxidative Stability of Champagne Base Wines Aged on Lees in Barrels: A 2-Year Study

“…Enrichment into antioxidant metabolites during barrel ageing and on lees provided a better capacity for ageing, as it is very important for Champagnes due to their process and especially on laths ageing that can last at least 15 months to many years [ 75 ]. Moreover, the sensory perceptions of base wines by oak-wood extracted compounds, such as lignans and coumarins, could also be affected such as sweetness, bitterness and acidity; these compounds are known for their antioxidant properties [ 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 ].…”

Antioxidants in Animal Nutrition: UHPLC-ESI-QqTOF Analysis and Effects on In Vitro Rumen Fermentation of Oak Leaf Extracts

“…Furthermore, fraction Qr/2/1 accounted for a substantial triterpene aglycones. According to literature data, bartogenic acid and its derivatives were isolated from oak heartwood [ 51 ] and wood [ 52 ], as well as different tetrahydroxyolean-12-ene-24,28-dioic acid derivatives [ 53 ]. However, little information is available in the literature on the isolation and identification of these metabolites in Q. robur L. leaves.…”

Screening for pancreatic lipase natural modulators by capillary electrophoresis hyphenated to spectrophotometric and conductometric dual detection

“…Extraction and purification of molecules from oak wood, grapes and wine: 11 natural molecules (Table 1) were extracted from oak wood, grapes and wine using centrifugal partition chromatography fractionation and HPLC purification [67][68][69][70][71]…”