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Your search keyword '"Stoll, Manfred"' showing total 4 results
Start Over Author "Stoll, Manfred" Journal journal of agricultural and food chemistry
4 results on '"Stoll, Manfred"'

3. Understanding Yeast Impact on 1,1,6-Trimethyl-1,2-dihydronaphthalene Formation in Riesling Wine through a Formation-Pathway-Informed Hydrolytic Assay

Author

Josh L. Hixson, Markus Herderich, Manfred Stoll, Jennifer R. Bellon, Yevgeniya Grebneva, Doris Rauhut, Grebneva, Yevgeniya, Bellon, Jennifer R, Herderich, Markus J, Rauhut, Doris, Stoll, Manfred, and Hixson, Josh L

Subjects
hydrolytic assay, Wine, Saccharomyces cerevisiae, Naphthalenes, Vineyard, TDN, chemistry.chemical_compound, yeast-mediated formation, acid hydrolysis, Aroma compound, Vitis, Food science, Aroma, Winemaking, biology, Riesling, food and beverages, General Chemistry, norisoprenoid, biology.organism_classification, Winery, Yeast, actinidol, chemistry, Fruit, Fermentation, Odorants, Viticulture, General Agricultural and Biological Sciences
Abstract

Refereed/Peer-reviewed The occurrence in Riesling wine of the potent odorant 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) is dependent upon vineyard and winemaking conditions, and TDN can have a prominent impact on the attributes of a wine after years in a bottle. As such, immediately assessing the impact of vineyard or winery treatments on future TDN formation requires forced creation of the aroma compound under non-wine-like conditions from other precursors. Here, we use a Box–Behnken approach and known TDN end points in commercial wines to optimize the conditions (pH, temperature, and time) of a “total TDN” hydrolytic assay for Riesling wine, which was intended to not interfere with yeast-derived formation pathways. The new assay (75 °C, pH 1.7, and 60 min) was used to determine the role of industry-relevant commercial yeasts as well as novel hybrid yeast strains on total TDN concentrations in young Riesling wines. While significant differences were observed between some yeasts, the impact of defoliation as a viticultural intervention outweighed yeast effects, suggesting that elevated TDN concentrations in wine are likely due to grape growing conditions and cannot be readily reduced or compensated for in the winery.

Published
2019

4. Variability of Constitutive Stilbenoid Levels and Profiles in Grape Cane ( Vitis vinifera L.) Depending upon Variety and Clone, Location in the Vineyard, Pruning Time, and Vintage.

Author

Besrukow P, Irmler J, Schmid J, Stoll M, Winterhalter P, Schweiggert R, and Will F

Subjects
Canes, Clone Cells chemistry, Farms, Stilbenes analysis, Vitis genetics
Abstract

Stilbenoids in grape cane ( Vitis vinifera L.) are bioactive compounds relevant for plant defense and the potential valorization of this byproduct. Our screening of grape cane from 102 varieties showed constitutive stilbenoid levels in a wide range (557-7748 mg/kg of dry weight). Analyses of genetically distinct clones of selected cultivars unraveled that intravarietal variability (e.g., cv. Riesling, 3236-6541 mg/kg) was higher than that across samples from a single clone but different vineyard positions (3017-3710 mg/kg). Furthermore, stilbenoid levels in samples obtained in October, December, and February (3 years, 2017-2019) showed pronounced quantitative and qualitative variability and the highest yields upon December pruning. For instance, vitisin B and ε-viniferin in cv. Pinot Noir and Accent were predominant in 2017 and 2019 (both >90% of total stilbenoids) but not in 2018 (both <55%) when temperatures were high and precipitation low. In brief, we report the variability of stilbenoid levels in grape cane depending upon genetic and environmental factors.

Published
2022
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