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Jaitz L.,University of Natural Resources and Life Sciences, Vienna | Siegl K.,Research Institute for Viticulture and Pomology HBLAuBA | Eder R.,Research Institute for Viticulture and Pomology HBLAuBA | Rak G.,Corvinus University of Budapest | And 3 more authors.
Food Chemistry | Year: 2010

A rapid LC-MS/MS method for quantification of phenols and polyphenols in authentic wine samples with unrivalled sensitivity was developed. Excellent limits of detection in the low μg L-1 range were achieved. Reversed phase HPLC employing sub-2 μm particles as stationary phase allowed high-throughput analysis with analysis times of 10 min for 11 compounds. The phenolic pattern was assessed in 97 authentic wine samples (stored under identical conditions without further treatment or modification) comprising eleven geographical Austrian regions, six grape varieties and five vintages. Canonical discriminant analysis was applied to the data set showing the suitability of the (poly)phenolic spectrum for classification of the wine samples. The method allowed a geographic discrimination of several grape varieties and a grape variety based discrimination of four regions. As a novel finding excellent (poly)phenol-based differentiation of the five investigated vintages (2003-2007) was achieved. © 2010 Elsevier Ltd. All rights reserved. Source


Michlmayr H.,University of Natural Resources and Life Sciences, Vienna | Nauer S.,Research Institute for Viticulture and Pomology HBLAuBA | Brandes W.,Research Institute for Viticulture and Pomology HBLAuBA | Schumann C.,Research Institute for Viticulture and Pomology HBLAuBA | And 3 more authors.
Food Chemistry | Year: 2012

It is now well established that wine-related lactic acid bacteria (LAB), especially Oenococcus oeni, possess glycosidase activities that positively contribute to wine aroma through the hydrolysis of grape-derived aroma precursors. In our recent studies, we have identified and characterised several LAB glycosidases with potential in these terms. Here, we report that both a glucosidase and an arabinosidase from O. oeni can release high amounts of monoterpenes from natural substrates under optimal conditions, indicating that these intracellular enzymes might play a significant role in the hydrolysis of aroma precursors during malolactic fermentation. The enzymes from O. oeni exhibited broad substrate specificities (release of both primary/tertiary terpene alcohols) and were even active in grape juice. Further, a sensory panel clearly preferred enzyme-treated Riesling wines over the controls and affirmed that the glycosidases from O. oeni could improve the typical Riesling aroma. © 2012 Elsevier Ltd. All rights reserved. Source

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