Wine and beer are nowadays the most popular alcoholic beverages, and the benefits of their moderate consumption have been extensively supported by the scientific community. The main source of wine ...and beer's antioxidant behavior are the phenolic substances. Phenolic compounds in wine and beer also influence final product quality, in terms of color, flavor, fragrance, stability, and clarity. Change in the quantity and quality of phenolic compounds in wine and beer depends on many parameters, beginning with the used raw material, its place of origin, environmental growing conditions, and on all the applied technological processes and the storage of the final product. This review represents current knowledge of phenolic compounds, comparing qualitative and quantitative profiles in wine and beer, changes of these compounds through all phases of wine and beer production are discussed, as well as the possibilities for increasing their content. Analytical methods and their importance for phenolic compound determination have also been pointed out. The observed data showed wine as the beverage with a more potent biological activity, due to a higher content of phenolic compounds. However, both of them contain, partly similar and different, phenolic compounds, and recommendations have to consider the drinking pattern, consumed quantity, and individual preferences. Furthermore, novel technologies have been developing rapidly in order to improve the polyphenolic content and antioxidant activity of these two beverages, particularly in the brewing industry.
Mlada rdeča vina izpostavljena kisiku lahko pod določenimi pogoji pridobijo na kakovosti. Proces mikrooksidacije je osnovna metoda, s katero lahko vplivamo na fenolno strukturo vin, ki skuša ...prilagajati količino dodanega kisika vinu z namenom povečati stabilnost barve, zmehčanja trpkih taninov in zmanjšanja neprijetnih arom. Proučevali smo vpliv mikrooksidacije na spremembo barve in vsebnosti fenolnih spojin vina modri pinot. Analize so vključevale določanje skupnih fenolov, taninov, netaninov, flavonoidov in neflavonoidov, antocianov, intenzitete barve, tona barve, deleža rdeče barve pri posameznih valovnih dolžinah (420, 520 in 620 nm), oceno koncentracije pigmenta odpornega na SO2 ter primerjavo končnega in kontrolnega vzorca v kemijskih parametrih (pH, prosti in vezani SO2, alkohol, skupni suhi ekstrakt, skupne, titrabilne in hlapne kisline). Rezultati so pokazali, da je mikrooksidacija povzročila spremembo barvnega značaja, izboljšanje intenzitete barve procesiranega vzorca v primerjavi s kontrolnim, vzpodbudila tvorbo polimernih barvil in kopigmentiranih kompleksov, s tem pa mehčanje taninov (polimerizacija fenolnih spojin) in stabilizacijo barve, ki je odporna na vezavo z SO2.
The effects of extended maceration (13 days) were investigated for extraction of trans-resveratrol and other phenolics from grapes of cultivar ‘Blaufränkisch’, and then during the subsequent ...maturation of the wine (250 days). Total phenolics and three subgroups of phenolics were followed. The concentrations of total phenolics, total flavonoids, and total anthocyanins, but not of total nonflavonoids, increased with extended maceration, and then decreased after 250 days of maturation. Trans- and cis-resveratrol concentrations increased following extended maceration and maturation (6.5, 2.9 mg/L, respectively). The maximum polydatin concentration was reached after only 6 days of maceration (10.9 mg/L). The antioxidant potential of the must increased following extended maceration (12.3 mmol DPPH2/L), and then remained unchanged for the red wine after maturation. Addition of trans-resveratrol to the red wine and into model solutions showed increased solubility and stability of trans-resveratrol in the red wines over the model solutions. Minor increases in antioxidant potential and better stability of malvidin-3-glucoside were also seen.
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•The extended maceration of grape berries and maturation of ‘Blaufrankish’ red wine increased concentration of resveratrols.•AOP increased during the maceration, and remained high after the 250 days of maturation.•During maturation concentrations of three anthocyanins and two catechins decreased, but of two phenolic acids increased.•The solubility and stability of trans-resveratrol in the red wine were better than that seen for a model wine solution.•AOP of the enriched red wine increased a little, a much larger increase was observed in the model wine solutions.
•Phenolics potentiate reactivity of SO2 in DPPH and Folin Ciocalteu assays.•SO2 contributes few tens percent to the antioxidant potential (AOP) of white wines.•Contribution of phenolics to the AOP of ...white wines is overestimated due to SO2.•Different experimental protocols can produce large variations in determined AOP.•Control of experimental conditions is essential for comparison of published studies.
The reactivity of SO2 with the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and in Folin Ciocalteu (FC) assays was analysed under different experimental conditions. There was significantly higher reactivity between SO2 and DPPH in buffered methanol than in methanol alone. When DPPH and FC assays were performed in a mixture of caftaric acid and SO2, there were synergistic effects that were more pronounced with the FC assay. Phenolics are an important parameter of wine quality, and their accurate characterisation in wine is essential. Analysis of white wines with DPPH and FC assays overestimates the contribution of phenolics to the antioxidant potential (AOP). SO2 contributes (from 20% to 45%) to the AOP of the white wines analysed. As SO2 reactivity depends highly on buffer composition, pH, time of incubation and other compounds, e.g. phenolics and aldehydes, different experimental protocols can produce large variations in AOPs, and therefore control of experimental conditions is extremely important.
The main objective of this study was to determine the impact of three different commercial yeasts and two lactic acid bacteria, as well as the use of oak (chips and staves) on the volatile phenol ...(VP) formation in Montenegrin aged red wines (Vranac, Kratosija and Cabernet Sauvignon) of the 2013 vintage. Standard chemical parameters of the wines were determined in order to establish relationship with VP. After three years of bottle aging, chemical parameters of wines (alcohol content, residual sugars (RS), pH, free and total SO2, anthocyanins) and VP (4-ethylphenol and 4-ethylguaiacol) were determined. Volatile phenols were found in 18 samples of Kratosija and 5 samples of Vranac. Volatile phenols were not detected in Cabernet Sauvignon wines. Kratosija as a grape variety from the Montenegrin terroir during 2013 vintage had the highest potential for the VP formation, while the highest content of 4-ethylphenol (2.84 mg/L) and 4-ethylguaiacol (0.52 mg/L) was determined in Vranac wine. It was demonstrated that VP would be formed in wines even with high alcohol content (>12.50 vol.%), low pH (<3.30) and with free SO2 concentrations at bottling of 30-35 mg/L.
Solvent composition has a large influence on measured antioxidant potential (AOP) of model polyphenols and red wines with 2,2-diphenyl-1-picrylhydrazyl (DPPH). We have shown that incorporation of ...aqueous buffer in the assay medium results in higher reactivity of catechin and caftaric acid, which are among major polyphenolic constituents of wines. Consequently, AOPs of red wines determined after 60 min of incubation at 25 °C in buffered methanol are 1.5–1.6-fold of values determined in methanol. Even in buffered methanol, wine polyphenols are not fully oxidized after 60 min. Only about half of Trolox equivalents were determined in comparison to the Folin–Ciocalteu assay. Buffer composition, pH, time of incubation, temperature, and concentration of antioxidants and DPPH all contribute to the resulting value of the AOP being standardized or at least strictly reported because minor differences in experimental procedures can account for large variations in determined AOP with DPPH for the same samples.
FTIR analysis of ash in wine Jug, Tjaša; Boni, Saverio; Košmerl, Tatjana
BIO Web of Conferences,
2017, Letnik:
9
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
In a modern oenological laboratory determination of ash is a limiting factor regarding the speed of analysis, since functional FTIR analysis of ash are not common yet. Therefore 324 samples were ...analysed by FTIR spectroscopy on TDI Bacchus 3 as well as ISO 17025 accredited reference method (OIV–MA–AS2–04: R2009) in two duplicates. FTIR spectra and reference data were uploaded into software for the calibration development and validation performed. Already the original TDI calibration was ready to use, showing satisfying results. However, we tried to improve it. On 324 spectra, we have looked for optimal wavelengths and mathematical models, which gave the best results. The developed calibration was then confirmed by method validation: repeatability, reproducibility and accuracy. The expanded measurement uncertainty calculated was 0.3 g/L, which I slightly higher than of the reference method used. We have found another advantage over classical method: there is no influence of the air pressure or moisture. Nevertheless, we were able to confirm that our reference method was free of systematic error induced by the influence of the weather. Anyway, we can conclude that analysis of ash in wine by FTIR spectroscopy is a promising, fast and reliable new method.
This review focuses on the considerable amount of research regarding volatile phenols production by Brettanomyces and on microbiological and technological parameters that influence development of ...these compounds during all stages of grape processing and winemaking. Also, volatile phenols impact on wine aroma and quality and prevention methods were discussed. The yeast genus Brettanomyces is the major microorganism that has the ability to convert hydroxycinnamic acids into significant concentration of phenolic compounds, especially of 4-ethylphenol and 4-ethylguaiacol, in red wine. When volatile phenols reach concentrations above the sensory threshold in wine, it is then characterized as wine with fault. In order to control the growth of Brettanomyces and preclude volatile phenols production, it is helpful to keep good quality of grape, winery sanitation, control of oxygen and sulphite level, as well as orderly check physiochemical composition of wine.
The main objective of this study was to investigate the influence of different commercial wine yeast strain combinations on wine varietal aroma and glutathione concentration. Four combinations of ...yeast strains were selected to produce Sauvignon Blanc wine under controlled conditions. The concentration of volatile thiols and methoxypyrazines in produced wines was quantified using GC-MS and the concentration of glutathione during fermentation was monitored and quantified using HPLC-FLD. Sensory analysis of wines was performed by a group of experienced wine assessors. The results indicated that the yeast strain combinations differed significantly in terms of their ability to release volatile thiols and to preserve glutathione levels, but had no impact on methoxypyrazine concentrations. In accordance with the chemical composition of wines, significant differences were found in their sensory quality. It can be concluded that the selection of an appropriate yeast strain combination for alcoholic fermentation presents the potential to greatly modulate wine aroma.
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•New method for the separation of magneto‐responsive bacteria at a certain stage of MLF.•Controlled attachment of magnetic nanoparticles to a bacterial surface.•Influence of attached ...magnetic nanoparticles on the bacterial viability.•Quick and effective method for the separation of lactic acid bacteria from wine.
A new method for magnetic separation of the magnetized lactic acid bacteria (LAB) Oenococcus oeni at a desired stage of the malolactic fermentation (MLF) in wine was developed. The method includes the bonding of functionalized magnetic nanoparticles to the bacterial surface in the suspension, the application of the “magneto‐responsive” bacteria (MRB) in the fermentation process and their magnetic separation from the wine using high‐gradient magnetic separation (HGMS). The controlled attachment of the superparamagnetic amino‐functionalized silica‐coated maghemite nanoparticles (aMNPs) to the O. oeni was developed. The MRB were applied in the MLF and separated from the fermentation process at a certain stage using the HGMS. From the results it was found that the magnetization of the bacteria using aMNPs attached to the cell surface had no influence on the O. oeni metabolism. The O. oeni with the attached magnetic nanoparticles were efficiently removed from the fermentation media using HGMS, which resulted in a complete stop of the fermentation process.
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