The aroma profile of five premium red wines has been studied by sensory descriptive analysis, quantitative gas chromatography-olfactometry (GC-O), and chemical quantitative analysis. The most ...relevant findings have been confirmed by sensory analysis. Forty-five odorants, including the most intense, were identified. At least 37 odorants can be found at concentrations above their odor threshold. A satisfactory agreement between GC-O and quantitative data was obtained in most cases. Isobutyl-2-methoxypyrazine, (E)-whiskey lactone, and guaiacol were responsible for the veggie, woody, and toasted characters of the wines, respectively. The sweet-caramel notes are related to the presence of at least five compounds with flowery and sweet notes. The phenolic character can be similarly related to the presence of 12 volatile phenols. The berry fruit note of these wines is related to the additive effect of nine fruity esters. Ethanol exerts a strong suppression effect on fruitiness, whereas norisoprenoids and dimethyl sulfide enhance fruity notes.
Summary Background & aims Epidemiological data suggest that moderate red wine consumption reduces cardiovascular mortality and the incidence of diabetes. However, whether these effects are due to ...ethanol or to non-alcoholic components of red wine still remains unknown. The aim of the present study was to compare the effects of moderate consumption of red wine, dealcoholized red wine, and gin on glucose metabolism and the lipid profile. Methods Sixty-seven men at high cardiovascular risk were randomized in a crossover trial. After a run-in period, all received each of red wine (30 g alcohol/d), the equivalent amount of dealcoholized red wine, and gin (30 g alcohol/d) for 4 week periods, in a randomized order. Fasting plasma glucose and insulin, homeostasis model assessment of insulin resistance (HOMA-IR), plasma lipoproteins, apolipoproteins and adipokines were determined at baseline and after each intervention. Results Fasting glucose remained constant throughout the study, while mean adjusted plasma insulin and HOMA-IR decreased after red wine and dealcoholized red wine. HDL cholesterol, Apolipoprotein A-I and A-II increased after red wine and gin. Lipoprotein(a) decreased after the red wine intervention. Conclusions These results support a beneficial effect of the non-alcoholic fraction of red wine (mainly polyphenols) on insulin resistance, conferring greater protective effects on cardiovascular disease to red wine than other alcoholic beverages. www.isrctn.org : ISRCTN88720134.
Nowadays, consumers demand red wines with deep colour, soft tannins and fruit scents, but these wines can only be obtained from grapes with complete phenolic maturity. Diverse methods have been ...proposed for measuring phenolic maturity. However, all these methods only provide the average value and do not consider any possible heterogeneity. Throughout ripening, grapes were separated according to their density, which revealed the existence of a large heterogeneity. Grapes at harvest were also separated by density in three groups. The higher the density of the grapes the higher ethanol content, pH, colour intensity, total phenolic index and anthocyanin and proanthocyanidin concentrations, and the lower the titratable acidity and bitterness of the wines. When the grapes were denser the wines were also better balanced in flavour and mouthfeel sensation. These results suggest that grape heterogeneity may influence the final wine composition and quality and therefore it should be considered at harvest.
► Commercial mannoproteins did not have an effect on colour stabilisation. ► Commercial mannoproteins did not affect the global tannin profile evolution. ► MP3 commercial mannoprotein stabilised ...growth of tannins with mDP between 8 and 14. ► There is an interaction between low and medium MW mannoproteins and proanthocyanidins.
Commercial oenological products containing mannoproteins have the purpose of preventing tartrate salts precipitation or achieving wines with a better mouth-feeling. The evaluation of the influence of three commercial mannoproteins on colour and tannin stability of three different red wines (two from Touriga Nacional and one from Alfrocheiro and Aragonês varieties) was studied. The evolution of colour through time was similar for all modalities, resulting in an increase of polymeric pigments and colour hue and a decrease of other parameters, suggesting that there was no influence of commercial mannoproteins on colour stability. The tannin profile evolution showed a possible stabilizing effect of one of the commercial products for tannins with an mDP between 8 and 14. It is possible that the commercial mannoproteins used in this work have some influence on the tannin aggregation evolution, contributing to the delay of tannin polymerisation in red wines.
This work studies the variability of the Saccharomyces cerevisiae present during the spontaneous fermentation of Garnacha grapes’ musts from a “Pago” winery from the east of Spain. The parameters ...used to select yeast are those related to growth, fermentative behaviour, and the influence on the wine’s aroma and polyphenolic composition. Yeast identification was performed by ITS analysis and typed by Hinfl mDNA restriction profile analysis. Growth and metabolic characteristics of the isolates were determined by laboratory-scale fermentations of sterile Garnacha must, and the composition of the polyphenolic and the volatile compounds, and the sensory attributes of the small-scale produced red wines were determined. Ten S. cerevisiae strains were isolated and characterized. Overall, strain 22H quickly grew, produced wines with moderate ethanol concentrations and low volatile acidity, and obtained the highest colour and aroma scores, plus a high score for sensory attributes.
In this paper, several linear multiple regression models of aroma descriptors were built from potential active odorants in Cabernet Sauvignon red wines in Changli County. The modified frequency (
...MF%) of ten aroma description terms in sample wines were evaluated by 30 panelists trained using the aroma standards of “Le Nez du Vin”. Aroma compounds of sample wines were detected by Solid Phase Microextraction-Gas Chromatography-Mass (SPME-GC-MS), and 65 aroma compounds were identified and quantified. Those aroma compounds with odor active values (OAV)
>
0.5 were chosen to build regression models for the eight characteristic aroma terms. Finally, five models were developed for five typical sensory terms: Blackcurrant, Bilberry, Green pepper, Vanilla and Smoked. These models were related to 13 aroma compounds. These compounds included 3-ethoxy-1-propanol, phenethyl acetate, 4-terpinenol, 2-hexen-1-ol, di-
tert-butyl-phenol, β-terpinenol, hexanoic acid, octanoic acid, ethyl myristate, ethyl 3-hydroxy butyrate, isobutyl alcohol and 4-methyl-5-butyl-2(3H)-furan. ANOVA statistical analysis indicated that all five models regressed at 95% significant levels.
t detections of the models showed regression coefficients of 99% or 95% significant levels. Correlation coefficients between the measured and predicted
Y ranged from 0.714 to 0.999.
trans-Resveratrol (TRA), is one of the indicators to evaluate the quality of red wines. In this study, a novel flexible electrochemical sensor using direct laser-induced graphene (LIG) technique that ...transforms the commercial Kapton tape into three-dimensional (3D) porous graphene was developed for sensitive detection of TRA molecules in red wines. For the first time, the strategy of ‘double layer’ (Kapton/polyimide) was employed to obtain the LIG with undamaged shape and excellent electrical properties. The mechanism of heat absorption and dissipation of laser-induced process was investigated in detail. The prepared electrochemical sensor with excellent repeatability, stability, reproducibility, and reliability, appears an excellent linear response within the TRA concentration range from 0.2 to 50 μmol L−1 and a low limit of detection (LOD) of 0.16 μmol L−1. Furthermore, the developed sensor can be applied for the evaluation of TRA level in red wines and grape skins with a satisfactory result. The sensor may be potential in analysis of active compounds in food or environmental samples.
A novel flexible electrochemical sensor using direct laser-induced graphene (LIG) technique that transforms the commercial Kapton tape into three-dimensional (3D) porous graphene was developed for sensitive detection of TRA molecules in red wines. Display omitted
•A flexible laser-induced porous graphene-based electrochemical sensor was developed.•A strategy of ‘double layer’ (Kapton/polyimide) was employed to obtain the LIG.•The sensor shows great electrochemical performance in trans-resveratrol detection.•This procedure can be further applied to other food or environmental analyses.
Insufficient acidity in grape berries from warm climate regions has been exacerbated due to global warming, thereby becoming a major concern for winemaking. The wine lactic acid bacterium ...Lactiplantibacillus plantarum has potential to ameliorate wine acidity by producing lactic acid from hexose metabolism, but its impact on wine compositions and sensory outcomes is not well studied. Here, we evaluated acidification and fermentation performance of indigenous L. plantarum in two inoculation regimes (i.e., reverse inoculation and co-inoculation) by conducting pilot-scale vinification using Cabernet Sauvignon with low acidity. Important parameters of the bio-acidified wines, including fermentation kinetics, basic oenological parameters, volatile and sensory profile were compared to those in wines produced by single Saccharomyces cerevisiae with/without chemical acidification. Total titratable acidity in L. plantarum wines were either comparable or significantly higher compared to the chemical acidification control. Chemical profiling reviewed remarkable differences in certain organic acids and major volatile compounds, especially an up to a five-fold, six-fold, and nine-fold increase in lactic acid, ethyl lactate and isoamyl lactate, respectively. Changes in chemical compositions of the bio-acidified wines resulted in differentiated sensory perception compared to the control wines. Except having higher scores for “wine acidity”, the flavour profile of the bio-acidified wines was shifted towards “jammy fruit” and “butter” aromas. Together, these findings highlighted the applicability of using L. plantarum to induce biological acidification along with modulation of wine flavour.
Resveratrol, a naturally occurring compound of various fruits such as grapes, is thought to possess chemopreventive properties. The levels of resveratrol in grapes and grape products including wine, ...varies from region to region and from one year to another. This paper reviews the resveratrol content in red wine based on relevant published data. Red wine contains an average of 1.9
±
1.7
mg
trans-resveratrol/l (8.2
±
7.5
μM), ranging from non-detectable levels to 14.3
mg/l (62.7
μM)
trans-resveratrol. In general, wines made from grapes of the Pinot Noir and St. Laurent varieties showed the highest level of
trans-resveratrol. No region can be said to produce wines with significantly higher level of
trans-resveratrol than all other regions. Levels of
cis-resveratrol follow the same trend as
trans-resveratrol. The average level of
trans-resveratrol-glucoside (
trans-piceid) in a red wine may be as much as 29.2
mg/l (128.1
μM), i.e., three times that of
trans-resveratrol.
A preparative HPLC method, which preserves wine aromas and isolates fruity characteristics in specific fractions, was applied to red wine aroma extracts. Various odor-active zones were detected in ...typical fractions by GC-O analysis of their extracts. Through further GC-MS analyses, the aromatic compounds responsible for 15 of these odoriferous zones were identified as various ethyl esters and alkyl acetates. In view of their olfactory thresholds, the concentrations of these compounds had no direct impact on the fruity aroma of red wines. Nevertheless, an overall sensory effect of “red-” or “black-berry” nuances was clearly established. Higher than average levels of ethyl propanoate, ethyl 2-methylpropanoate, and ethyl 2-methylbutanoate were involved in black-berry aromas, whereas ethyl butanoate, ethyl hexanoate, ethyl octanoate, and ethyl 3-hydroxybutanoate conferred red-berry aromas.
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