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Weingart G.,University of Natural Resources and Life Sciences, Vienna | Weingart G.,University of Vienna | Schwartz H.,University of Natural Resources and Life Sciences, Vienna | Schwartz H.,University of Vienna | And 2 more authors.
European Food Research and Technology | Year: 2010

This paper describes the development and application of a fast and simple headspace solid phase microextraction GC-MS method for simultaneous determination of geosmin and 2,4,6-trichloroanisole (2,4,6-TCA), two main contributors to off-flavors in wine. The compounds were adsorbed onto a polydimethoxysiloxane (PDMS) fiber at 35 °C for 40 min without prior equilibration, thermally desorbed and analyzed by GC-MS in the selected ion monitoring mode. The parameters for adsorption onto and desorption from the fiber were optimized. This method was applied to analysis of 118 Austrian white and red wines, which were also characterized by sensory analysis. Geosmin was above the limit of detection (0.5 ng/L) in 110 wines (93%) and additionally quantified (>2 ng/L) in 65 wines (55%). It could be detected in wines of each off-flavor (moldy, corky, damp, musty, rotten, woody, grassy) in concentrations up to 16.7 ng/L and even in 90% of the sensorially faultless wines (up to 6.5 ng/L). On the other hand, 2,4,6-trichloroanisole was detected only in 24 wines (20% of all investigated wines) and above the limit of quantitation (2 ng/L) only in 5 wines (4%) sensorially classified as corky; corky and moldy plus other defects; or faultless in concentrations up to 14.3 ng/L. These results show that geosmin is more prevalent than 2,4,6-TCA and that chemical analysis is required especially when other wine characteristic flavors cover beginning off-flavors. © 2010 Springer-Verlag.

Bohner A.,Agricultural Research and Education Center | Unterweger P.,Agricultural Research and Education Center | Rohrer V.,Agricultural Research and Education Center | Sobotik M.,Phytosociological Institute | And 2 more authors.
Acta Horticulturae | Year: 2014

For a successful cultivation of V. myrtillus, its habitat requirements have to be known. Especially, the pH dependent soil chemical properties in the root-room are of utmost importance. Therefore, soil analyses in contrasting habitat types and plant analyses were done. Differences and similarities in the mineral nutrient contents in leaves and stems of V. myrtillus collected from different habitat types were investigated. V. myrtillus grows on very acid soils rich in humus but poor in plant available nitrogen. The calcifuge dwarf shrub is adapted to the low and disharmonic nutrient supply in the root-room, resulting from a relative excess of aluminium, iron and potassium and a complementary lack of calcium and magnesium at the exchange complex. The leaves and stems of V. myrtillus contain high amounts of manganese, which is abundantly available at low pH values. Furthermore, the plants have a relatively high absorption capacity for calcium and their requirements for nitrogen, potassium and phosphorus seems to be low. There are only little differences in the mineral nutrient contents in leaves and stems of V. myrtillus collected from contrasting habitat types. At higher altitudes, roots of V. myrtillus are restricted to the uppermost 20 cm, whereas at lower altitudes rooting depth is up to 50 cm.

Liszt K.I.,University of Vienna | Liszt K.I.,Christian Doppler Laboratory | Eder R.,Federal College and Research Institute for Viticulture and Pomology | Wendelin S.,Federal College and Research Institute for Viticulture and Pomology | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015

Organic acids of wine, in addition to ethanol, have been identified as stimulants of gastric acid secretion. This study characterized the influence of other wine compounds, particularly phenolic compounds, on proton secretion. Forty wine parameters were determined in four red wines and six white wines, including the contents of organic acids and phenolic compounds. The secretory activity of the wines was determined in a gastric cell culture model (HGT-1 cells) by means of a pH-sensitive fluorescent dye. Red wines stimulated proton secretion more than white wines. Lactic acid and the phenolic compounds syringic acid, catechin, and procyanidin B2 stimulated proton secretion and correlated with the pro-secretory effect of the wines. Addition of the phenolic compounds to the least active white wine sample enhanced its proton secretory effect by 65 ± 21% (p < 0.05). These results indicate that not only malic and lactic acid but also bitter and astringent tasting phenolic compounds in wine contribute to its stimulatory effect on gastric acid secretion. © 2015 American Chemical Society.

Castellanos-Morales V.,Universidad Michoacana de San Nicolás de Hidalgo | Villegas J.,Universidad Michoacana de San Nicolás de Hidalgo | Wendelin S.,Federal College and Research Institute for Viticulture and Pomology | Vierheilig H.,CSIC - Experimental Station of El Zaidín | And 2 more authors.
Journal of the Science of Food and Agriculture | Year: 2010

BACKGROUND: Arbuscular mycorrhizal fungi (AMF) increase the uptake of minerals from the soil, thus improving the growth of the host plant. Nitrogen (N) is a main mineral element for plant growth, as it is an essential component of numerous plant compounds affecting fruit quality. The availability of N to plants also affects the AMF-plant interaction, which suggests that the quality of fruits could be affected by both factors. The objective of this study was to evaluate the influence of three N treatments (3, 6 and 18 mmol L-1) in combination with inoculation with the AMF Glomus intraradices on the quality of strawberry fruits. The effects of each factor and their interaction were analysed. RESULTS: Nitrogen treatment significantly modified the concentrations of minerals and some phenolic compounds, while mycorrhization significantly affected some colour parameters and the concentrations of most phenolic compounds. Significant differences between fruits of mycorrhizal and non-mycorrhizal plants were found for the majority of phenolic compounds and for some minerals in plants treated with 6 mmol L-1 N. The respective values of fruits of mycorrhizal plants were higher. CONCLUSION: Nitrogen application modified the effect of mycorrhization on strawberry fruit quality. © 2010 Society of Chemical Industry.

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