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VIIIth Conference on Medicinal and Aromatic Plant Research: Bonn, 10. – 13. September 2018, Abstracts of Oral Presentations and Posters
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Study on current status and climatic characteristics of wine regions in China
Get PDFThe aim of this paper is to improve the knowledge of the current status and climatic characteristics of Chinese wine regions. An investigation of Chinese winegrowing regions, which concerned the distribution, area and cultivars, was conducted using "questionnaires + expert consultation + available literature". On the basis of the results of the investigation, a map was drawn to depict the distribution of Chinese wine regions. Furthermore, observation records of weather stations located within winegrowing zones during 1982–2011 were employed to analyze the climatic characteristics of each region by using the climatic indices of frost-free season (FFS), dryness index (DI), and extremely low temperature (ELT). According to the findings of the investigation, wine grapes have been widely cultivated in 179 counties of China, with a total cultivation area of 163,200 ha. \u27Cabernet Sauvignon\u27 was the most widely cultivated variety. The analysis of the climatic characteristics revealed a regional difference within and between wine regions. Moreover, most wine regions were suitable for wine production in terms of the climatic indices, which in turn verified the applicability of the climate indices system
Multi-annual comparisons demonstrate differences in the bunch rot susceptibility of nine Vitis vinifera L. \u27Riesling\u27 clones
Get PDFBotrytis bunch rot is a major fungal disease of grapevines, and causes severe economic damage worldwide. Under humid climatic conditions, the development of bunch rot on grapes cannot be suppressed completely. Selection of planting material with lower bunch rot susceptibility represents one of the most efficient long-term tools in the complex bunch rot minimisation strategy. The present investigation conducted over four consecutive years (2013-2016) under the environmental conditions of the Moselle valley aimed at (i) detecting consistent differences in the bunch rot susceptibility within a group of nine commercially available Vitis vinifera L. \u27White Riesling\u27 clones, (ii) investigating potential underlying causes and (iii) deriving recommendations for \u27Riesling\u27 clone selection in practical viticulture. Disease severity and grape maturity (total soluble solids) progress could be well simulated by sigmoidal curves (R2 > 0.89; P < 0.038). On average of all four years, the dates when 5 % bunch rot disease severity were reached differed significantly by 9 days between the clone with the earliest epidemic (Trier 34) and the clone with the latest epidemic (Heinz 65). Multi-annual results enabled a classification of the nine clones according to (i) their relative bunch rot susceptibility as well as (ii) their relative precocity. Based on this, practical recommendations concerning a targeted clone selection as an integral long-term tool (i) in Integrated Pest Management contributing to pesticide reduction in viticulture as well as (ii) in the viticultural climate change adaptation strategy were derived
Volatile compounds and phenolic composition of skins and seeds of \u27Cabernet Sauvignon\u27 grapes under different deficit irrigation regimes
Get PDFAroma compounds and skin and seed polyphenols are determinants of wine composition. The aim of this study was to determine the effect of different post-veraison deficit irrigation strategies on volatile profile and the chemical composition of grape skin and seeds in a \u27Cabernet Sauvignon\u27 vineyard in Valencia (Spain). Besides a non-irrigated regime (rainfed), irrigation treatments consisted of replacing 25, 50 and 75 % of the estimated crop evapotranspiration (ETC). When compared to rainfed vines, watering during post-veraison at 75 % of the ETC, decreased concentrations of alcohols but increased those of aldehydes such as hexanal, related to herbaceous (non-desirable) aromas in wines. Irrigating at 25 % or 50 % of ETC resulted in similar concentrations of grape volatile compounds than rainfed vines. There was also a general trend in a reduction in skin to flesh ratio as irrigation regime increased. The concentration of skin anthocyanins and tannins increased with water applications, but seed tannins decreased in the most irrigated regimes. This suggests different effects of water stress on skin and seed polyphenol synthesis and accumulation. For the tannin content, water stress provoked higher tannin mean degree polymerization values, which positively affect must astringency. Under the experimental conditions of the present study, watering at 50 % ETC during post-veraison is the recommended irrigation strategy for optimizing grape composition and improving yield in comparison with rainfed vines
Immobilisation of glycosidases from commercial preparation on magnetic beads: Part 2: Aroma enhancement in wine using immobilised glycosidases
Get PDFMost of the terpenes in wines are conjugated to various sugars, representing a significant reservoir of aromatic precursors. To promote the release of these terpenes, certain enzymes, such as β-glucosidase, α-arabinosidase and α-rhamnosidase, are necessary. A simple and cost-effective procedure for the immobilisation of multiple glycosidase activities (β-D-glucopyranosidase, α-L-arabinofuranosidase, α-L-rhamnopyranosidase and β-D-xylopyranosidase) from commercial Aspergillus niger preparation onto magnetic beads as carriers was developed as reported in Part 1 (Ferner et al. 2016).The aim of this work was to analyse a possible application of this immobilised biocatalyst due to its well-known advantages over soluble enzyme preparations – that is, control of the reaction process and preparation of enzyme-free products. Volatile compounds were analysed by gas chromatography (mass spectrometric detection). After the treatment of the model wine with different glycosides and white wine with immobilised glycosidases, the amount of free terpenes was significantly increased with respect to that of the control wine.The results of this study are of considerable interest for possible future applications of immobilised enzymes in the wine-making industry
Molekular-sensorische Charakterisierung wertgebender Scharfstoffe in gestresstem und nativem, schwarzem Pfeffer (Piper nigrum L.)
Get PDFUntersuchung des mikrobiellen trans-Resveratrol-Metabolismus in vivo und Identifizierung metabolischer Phänotypen
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