Twenty three strains of Penicillium expansum, as a predominant species, were isolated from 23 (92%) out of 25 grape samples of 17 different grape varieties. The results of the identification of P. expansum strains were confirmed by a PCR method. Most of the isolates of P. expansum (21/23, 91%), when tested for toxigenicity, were bi-toxigenic: they produced citrinin (CIT) and particularly high amounts of patulin (PAT). A validated UPLC-MS/MS method for the determination of PAT and CIT was applied. The limits of quantification (LOQ) for PAT and CIT in grape must and toxigenicity testing samples were 100 and 2 ng/g, respectively. The results of PAT and CIT quantification in 23 grape must samples demonstrated the occurrence of PAT in 10 (43%) grape must samples (mean: 171 ng/g; median: 50 ng/g; and range: 143-644 ng/g) and the occurrence of CIT in two (9%) grape must samples (mean: 1 ng/g; median: 1 ng/g; and range: 2.5-3.5 ng/g). This is the first report on the natural occurrence of CIT in grape must. A validated HPLC-UV-VIS method for the determination of PAT in wine samples was applied, and concentrations in all 23 wine samples were below the LOQ (<10 ng/g).

• MeSH
• citrinin analýza   MeSH
• dietární expozice MeSH
• druhová specificita MeSH
• limita detekce MeSH
• patulin analýza   MeSH
• Penicillium klasifikace   izolace a purifikace   MeSH
• polymerázová řetězová reakce MeSH
• reprodukovatelnost výsledků MeSH
• spektrofotometrie ultrafialová MeSH
• tandemová hmotnostní spektrometrie MeSH
• víno analýza   MeSH
• Vitis chemie   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH

Grape canes are a waste product from viticulture that show potential as an industrially extractable source of stilbenes, which are valuable for medical and other purposes. In this work, grape canes collected in three consecutive years (2014-2016) at six different places in South Moravia, Czech Republic were extracted, and the contents oftrans-resveratrol,trans-ε-viniferin, and r2-viniferin were determined by high-performance liquid chromatography. The study included three blue grape varieties ofVitis viniferaL. (Cabernet Moravia, Blaufränkisch, and Piwi variety Laurot) and four white grape varieties (Chardonnay, Green Veltliner, Piwi variety Hibernal, and Piwi variety Malverina). From the viewpoint of producing extracts with high stilbenes content, the Hibernal variety is clearly the best. The mean amounts of the stilbenes for this variety at all localities and for all three years were 4.99 g/kg fortrans-resveratrol, 3.24 g/kg fortrans-ε-viniferin, and 1.73 g/kg for r2-viniferin. The influence of vintage, locality, and variety on the amounts of stilbenes was studied using PCA analysis. In contrast to expectations, there was no strong impact of locality on stilbenes content. The differences were varietal for most varieties, regardless of the area of cultivation. Laurot and Hibernal varieties did differ significantly in that respect, however, as they exhibited clear dependence on location.

• MeSH
• benzofurany analýza   MeSH
• polyfenoly analýza   MeSH
• rostlinné extrakty analýza   chemie   MeSH
• stilbeny analýza   chemie   MeSH
• Vitis chemie   MeSH
• Publikační typ
• časopisecké články MeSH

Grape cane, leaves and grape marc are waste products from viticulture, which can be used to obtain secondary stilbene derivatives with high antioxidant value. The presented work compares several extraction methods: maceration at laboratory temperature, extraction at elevated temperature, fluidized-bed extraction, Soxhlet extraction, microwave-assisted extraction, and accelerated solvent extraction. To obtain trans-resveratrol, trans-ε-viniferin and r2-viniferin from grape cane of the V. vinifera variety Cabernet Moravia, various conditions were studied: different solvents, using powdered versus cut cane material, different extraction times, and one-step or multiple extractions. The largest concentrations found were 6030 ± 680 µg/g dry weight (d.w.) for trans-resveratrol, 2260 ± 90 µg/g d.w. for trans-ε-viniferin, and 510 ± 40 µg/g d.w. for r2-viniferin. The highest amounts of stilbenes (8500 ± 1100 µg/g d.w.) were obtained using accelerated solvent extraction in methanol.

• MeSH
• časové faktory MeSH
• chemická frakcionace metody   MeSH
• hole * MeSH
• nukleární magnetická rezonance biomolekulární MeSH
• polyfenoly chemie   izolace a purifikace   MeSH
• rostlinné extrakty chemie   izolace a purifikace   MeSH
• rozpouštědla MeSH
• stilbeny chemie   izolace a purifikace   MeSH
• teplota MeSH
• Vitis chemie   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Pressurized hot water extraction (PHWE) was employed to prepare extracts from dried grape skin of two wine grape varieties (St. Laurent and Alibernet) at various temperatures (from 40 up to 120°C) and amounts of sample (0.5, 1.0 and 1.5 g). To assess the antioxidant activity of the extracts, electron paramagnetic resonance (EPR) spectroscopy was applied involving DPPH and ABTS(+) assays. Other extract characteristics including HPLC profile of anthocyanins and total phenolic compound content were obtained as well. PHWE has also been compared with earlier results of extractions of the same grape skin samples with compressed methanol and compressed ethanol under the conditions of pressurized fluid extraction (PFE). From this comparison, PHWE emerges as the more benign and efficient extraction method to recover valuable phenolic antioxidants from grape skins for the prospective use in functional food supplements.

• MeSH
• antioxidancia chemie   MeSH
• chemická frakcionace metody   MeSH
• elektronová paramagnetická rezonance metody   MeSH
• epidermis rostlin chemie   MeSH
• rostlinné extrakty chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• tlak MeSH
• Vitis chemie   MeSH
• voda chemie   MeSH
• vysoká teplota MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Detection of grapes in real-life images is a serious task solved by researchers dealing with precision viticulture. In the case of white wine varieties, grape detectors based on SVMs classifiers, in combination with a HOG descriptor, have proven to be very efficient. Simplified versions of the detectors seem to be the best solution for practical applications. They offer the best known performance versus time-complexity ratio. As our research showed, a conversion of RGB images to grayscale format, which is implemented at an image preprocessing level, is ideal means for further improvement of performance of the detectors. In order to enhance the ratio, we explored relevance of the conversion in a context of a detector potential sensitivity to a rotation of berries. For this purpose, we proposed a modification of the conversion, and we designed an appropriate method for a tuning of such modified detectors. To evaluate the effect of the new parameter space on their performance, we developed a specialized visualization method. In order to provide accurate results, we formed new datasets for both tuning and evaluation of the detectors. Our effort resulted in a robust grape detector which is less sensitive to image distortion.

• MeSH
• rotace MeSH
• support vector machine * MeSH
• víno analýza   MeSH
• Vitis * MeSH
• Publikační typ
• časopisecké články MeSH

Hyphenation of micro-liquid and ultra-performance liquid chromatography with a hybrid (QqTOF) tandem mass spectrometry was studied from the viewpoint of their applicability for monitoring of anthocyanin dyes in various cultivars and different vintages of red wine. After appropriate optimization both techniques proved to be suitable for this task. UHPLC system provided lower LOD and LOQ values as well as higher productivity and precision of retention parameters and peak areas with respect to micro-LC method. On the other hand, micro-LC method offers significant savings of mobile phase, less contamination of ion source of mass spectrometer and makes the nebulization process in electrospray much easier. In combination with principal component analysis (PCA), the method allows to elucidate long-term relations in a complete set of certified red wine cultivars grown in South Moravia (certified in Czech Republic until year 2005). Among the studied varieties Rubinet exhibit a specific anthocyanin profile. Especially interesting is a high content of 3-coumaroylglucoside-5-glucosides of malvidin and peonidin. Those dyes can be used as markers of artificial color enhancement. Principal component analysis applied to data processed with regard to enzymatic activity markedly facilitate classification among varieties. This approach allows resolution of teinturiers, variety Blaufränkish and partial classification of other varieties.

• MeSH
• analýza hlavních komponent MeSH
• anthokyaniny analýza   MeSH
• hmotnostní spektrometrie metody   MeSH
• víno analýza   klasifikace   MeSH
• Vitis MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

Many different yeast species have been isolated from grapes and musts worldwide. The diversity and frequency of yeasts depend on a number of factors such as the grape variety, the physical damage of the grapes, the weather conditions and the chemical composition of must. A total of 366 isolates were associated with the three grape cultivars: Blue Frankish, Green Veltliner and Sauvignon blanc over four consecutive years. Yeast cultures were isolated from the grapes and from the fermenting musts after the first and seventh days. The ascomycetous yeasts of the genera Aureobasidium, Candida, Hanseniaspora, Metschnikowia, Pichia, Saccharomyces and Saccharomycopsis together with basidiomycetous yeasts of the genera Cryptococcus, Dioszegia, Filobasidium, Rhodotorula and Sporidiobolus were associated with the three grape varieties. Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia kluyveri, Pichia kudriavzevii and Sporidiobolus pararoseus were found on the berries in significant amounts. P. kluyveri and P. kudriavzevii were more associated with the damaged grapes, whereas Sp. pararoseus with intact ones. H. uvarum and M. pulcherrima were present on both types of grapes almost equally. The yeast composition and quantitative representation of yeast species varied over the grape varieties and the years examined. Although the basidiomycetous species formed a significant proportion of the yeast population in some individual grape variety/year combinations, the ascomycetous species were dominant.

• MeSH
• biodiverzita * MeSH
• DNA fungální chemie   genetika   MeSH
• fungální RNA genetika   MeSH
• fylogeneze MeSH
• geny rRNA MeSH
• houby klasifikace   genetika   izolace a purifikace   MeSH
• ribozomální DNA chemie   genetika   MeSH
• RNA ribozomální genetika   MeSH
• sekvenční analýza DNA MeSH
• víno mikrobiologie   MeSH
• Vitis mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Slovenská republika MeSH

The diversity of yeasts and yeast microorganisms on grapes and, consequently, in musts may be strongly influenced by using Cu2+ products. The effect of Cu2+ concentration on the growth of native yeast strains isolated from grapes and grape must of three grape varieties was studied. The growth of H. uvarum, P. kluyveri, P. kudriavzevii, C. californica, F. elegans, R. bacarum and Sc. crataegensis was inhibited in the presence of a minimum concentration of 0.5 mM Cu2+. The growth of S. cerevisiae, Cr. magnus, R. glutinis and Sp. pararoseus depended on the strain tested. The strains of A. pullulans, M. pulcherrima, C. oleophila, P. terricola, R. nothofagi and R. minuta were growing at increasing Cu2+ concentrations but their growth was reduced by prolongation of the lag phase compared with their growth in the absence of Cu2+. The growth reduction of ethanol-tolerant yeast strains at higher concentration of Cu ions shows the effect of the prolonged action of wine fermentation. Autochthonous yeast strains resistant to higher Cu2+ concentrations (C. oleophila, M. pulcherrima, R. minuta) appear to be an appropriate solution to reduction of Cu residues in the fermenting must.

• MeSH
• antifungální látky * MeSH
• kultivační média MeSH
• kvasinky * chemie   MeSH
• měď * chemie   MeSH
• mikrobiologické techniky metody   přístrojové vybavení   využití   MeSH
• Vitis mikrobiologie   MeSH

Kultivar Aglianico je velmi stará odrůda červeného vína pocházející z regionu Campania v jižní Italii. Do nedávna bylo víno vyráběno fermentací pomocí kvasinek vyskytujících se na hroznech a ve sklepě. Mikroflora ulpívající na hroznech je složena především z kvasinek se slabými fermetačními a oxidačními schopnostmi, které nepatří do skupiny Saccharomyces. Naproti tomu většina kmenú kvasinek přítomných ve sklepě patří mezi sacharomycety. Úkolem této práce bylo vybrat nové kombinace kmenů kvasinek izolovaných z přirozeně se vyskytující mikroflory hroznů Aglianico a vinného sklepa lokalizovaného v irpinské oblasti a tyto kombinace kvasinek využít ke zlepšení organoleptických a sensorických vlastností takto připravených vín. Kvasinky izolované z hroznů i sklepa byly charakterizovány po stránce morfologické, biochemické a technické. Tyto kvasinky patří zejména mezi rody Saccharomyces, Hanseniaspora, Kloeckera, Rhodotorula, Metschnikowia and Candida. Mezi těmito kvasinkami měly nejlepší vlastnosti při přípravě vína dva kmeny (AGSW15 a FLOSW4), identifikované jako H. uvarum a S. cerevisiae na základě sekvenční analýzy úseku D1/D2 26S rDNA. Tyto kvasinky, použité při poloprovozní fermentaci, úspěšně dominovaly v průběhu alkoholické fermentace a ve zlepšení organoleptických vlastností potvrzených technikou SPME-GC/MS. Dosažené výsledky podporují použití vybraných kmenů kvasinek k zahájení fermentace umožňující zachovat zvláštnosti charakteristické pro toto typicky regionální víno.

Aglianico cultivar is an ancient red grape variety native of Campania region of the Southern of Italy. Until a few decades ago, wine was produced by natural fermentation carried out by autochthonous yeasts present on the grapes and in the cellar. The grapes epiphytic microflora is prevalently composed of apiculate yeasts with a poor fermentative power and by oxidative yeasts, belonging to nonSaccharomyces group. On the other hand, most of the yeast strains present in the cellar belong to Saccharomyces “sensu stricto”. The aim of this work was the selection of new combinations of yeast strains isolated from the autochthonous microflora of Aglianico grapes and wine cellar, located in the Irpinian area, and their use in winemaking process to improve the organoleptic and sensory peculiarities of the wine obtained. The yeasts isolated from grapes and cellar were characterized by morphological, biochemical, and technological analysis. They belonged mainly to the genus Saccharomyces, Hanseniaspora, Kloeckera, Rhodotorula, Metschnikowia and Candida. Among these yeasts the two strains (AGSW15 and FLOSW4) that showed the best winemaking performance were selected and identified as H. uvarum and S. cerevisiae by 26S rDNA D1/D2 region sequence analysis. These yeasts, when utilized in cellar for semi-industrial-scale fermentations, successfully dominate the alcoholic fermentation and contributed to the improvement of the wine organoleptic qualities as assessed by the flavor profile obtained through the SPME-GC/MS technique. These results clearly suggest the utilization of these selected strains in autochthonous fermentation starter to preserve the peculiarities of this typical regional wine.

• MeSH
• fermentace MeSH
• kvasinky * izolace a purifikace   klasifikace   růst a vývoj   MeSH
• mikrobiální viabilita MeSH
• víno * analýza   MeSH
• Vitis * mikrobiologie   MeSH

Many studies have already proven the positive effects of flavonoids on organisms. There are many plants which content important amounts of these secondary metabolites in their bodies, one of those being certainly vine (Vitis vinifera). The consumption of wine products is very popular all over the world and it is also connected with the health beneficial effects that it provides. Red wines content more flavonoids then other white or rosé varieties. It is mainly the consequence of the winemaking process during which the grape skin is either removed of left to release its secondary metabolite content, in case of the red and partially the rosé varieties

• MeSH
• antioxidancia MeSH
• flavonoidy * metabolismus   terapeutické užití   MeSH
• lidé MeSH
• víno * MeSH
• Vitis MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH