grape
Dotaz
Zobrazit nápovědu
It is estimated that more than 20% of processed apples and grapes are discarded as waste, which is dominated by pomace rich in malic acid that could be converted to high-value organic acids or other chemicals. A total of 98 yeast strains isolated from apple, grape, and plum wastes were evaluated for their ability to degrade malic acid relative to known yeast strains. Most (94%) of the new isolates degraded malic acid efficiently (> 50%) in the presence and absence of exogenous glucose, whereas only 14% of the known strains could do so, thus confirming the value of exploring (and exploiting) natural biodiversity. The best candidates were evaluated in synthetic media for their ability to convert malic acid to other valuable products under aerobic and oxygen-limited conditions, with two strains that produced ethanol and acetic acid as potential biorefinery products during aerobic cultivations and oxygen-limited fermentations on sterilized apple and grape pomace. Noteworthy was the identification of a Saccharomyces cerevisiae strain that is more efficient in degrading malic acid than other members of the species. This natural strain could be of value in the wine-making industry that often requires pH corrections due to excess malic acid.
The main by-product of wine-making is grape marc. With proper treatment, grape marc may return to the vineyard as a fertiliser. This study deals with the vermicomposting of grape marc in a continuous feeding system in outdoor conditions for more than 12 months. The N-NH4+, dissolved organic carbon (DOC), and N-NH4+/N-NO3- contents were greater in the top layers. The pH value was about 8 in all the layers. The electrical conductivity was the greatest in the bottom layer. The ion-exchange capacity did not modify significantly during vermicomposting. The microbial biomass was the greatest in the upper layer, as well as the number and the biomass of the earthworms. The process of vermicomposting seems to be an ideal way of processing residues from the winemaking industry. This vermicompost has very good properties for use as a fertiliser, and for returning the nutrients and organic matter to the soil, for example, in a vineyard.
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 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
This paper investigates the in vitro antimicrobial potential of 15 grape phenolic compounds of various chemical classes (phenolic acids, stilbenes and flavonoids) using the broth microdilution method against yeasts and acetic acid bacteria frequently occurring in deteriorated wine. Pterostilbene (MICs=32-128 μg/mL), resveratrol (MICs=256-512 μg/mL) and luteolin (MICs=256-512 μg/mL) are among six active compounds that possessed the strongest inhibitory effects against all microorganisms tested. In the case of phenolic acids, myricetin, p-coumaric and ferulic acids exhibited selective antimicrobial activity (MICs=256-512 μg/mL), depending upon yeasts and bacteria tested. In comparison with potassium metabisulphite, all microorganisms tested were more susceptible to the phenolics. The results revealed the antibacterial and antiyeast effects against wine spoilage microorganisms of several highly potent phenolics naturally occurring in grapes. These findings also provide arguments for further investigation of stilbenes as prospective compounds reducing the need for the use of sulphites in winemaking.
- MeSH
- Bacteria účinky léků růst a vývoj MeSH
- fenoly farmakologie MeSH
- flavonoidy farmakologie MeSH
- kontaminace potravin prevence a kontrola MeSH
- kvasinky účinky léků růst a vývoj MeSH
- kyselina octová metabolismus MeSH
- mikrobiální testy citlivosti MeSH
- potravinářská mikrobiologie MeSH
- prospektivní studie MeSH
- siřičitany farmakologie MeSH
- stilbeny farmakologie MeSH
- víno mikrobiologie MeSH
- Vitis chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie 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
The aim of this work was to study the effect of the daily ingestion of a purified anthocyanin extract from red grape skin on rat serum antioxidant capacity (ORAC) and its safety for the intestinal epithelium. The study was carried out in rats orally administered with the extract for 10 days in either normal physiological conditions or exposed to a pro-oxidant chemical (CCl(4)). The oral administration of the extract significantly (P<0.05) enhanced the ORAC value of the deproteinised serum of about 50 % after 10 days of ingestion. Anthocyanin administration was also able to reverse completely the decrease in the serum ORAC activity induced by the CCl(4) treatment. Experiments with Ussing chamber mounted intestine allowed to exclude any toxicity of the extract for the intestinal epithelium. In conclusion, our results demonstrate that the purified anthocyanin extract from red grape skin enhances the total antioxidant capacity of the serum in either normal physiological condition or during oxidative stress induction, revealing a protective role against the decrease in the serum antioxidant capacity induced by a pro-oxidant compound.
- MeSH
- anthokyaniny aplikace a dávkování izolace a purifikace krev MeSH
- antioxidancia metabolismus MeSH
- biologické markery krev MeSH
- jejunum metabolismus účinky léků MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- rostlinné extrakty aplikace a dávkování izolace a purifikace MeSH
- sérum fyziologie MeSH
- Vitis MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- srovnávací studie MeSH
