2,097 research outputs found
Chemical evaluation of Carcavelos fortified wine aged in portuguese (Quercus pyrenaica) and french (Quercus robur) oak barrels at medium and high toast
Adega do Casal Manteiga is a winery, publicly owned by the Municipality of Oeiras that produces Carcavelos
fortified wine. Carcavelos fortified wine is an appellation of origin and demarcated as D.O.P. (Denominação de
Origem Protegida). This study examines the effects of barrels made from botanical species (Quercus pyrenaica, and
Quercus robur) and toasting method (medium and high) on a single vintage wine that has been aged for 8 years.
Twenty barrels were used, with five replicates for each factor. The barrels were fabricated and toasted using the
same cooperage, J.M. Gonçalves in Portugal. Significant differences were seen between the species Q. robur and
Q. pyrenaica, with an impact on total phenolic content, including both flavonoids and non-flavonoids. The total
phenols of the wine aged in Q. pyrenaica barrels was significantly higher than in the Q. robur barrels, and
Q. pyrenaica contained more flavonoids than Q. robur in medium and high toast barrels. Q. pyrenaica showed more
non-flavonoid compounds than Q. robur inhigh and medium toasted barrels, but this difference in non-flavonoids
was only statistically significant in the high toasted barrels. The degree of toasting had significant effects on the
flavonoid content of the wine, as well as the tanning power. Flavonoid content increased for both Q. pyrenaica and
Q. robur in the wines that were aged in high tasted barrels compared to those that were medium toasted. The tannin
power decreased for both Q. pyrenaica and Q. robur when the toasting increasedinfo:eu-repo/semantics/publishedVersio
Interactions between protein fining agents and proanthocyanidins
A comparative fining trial was conducted in a laboratory scale to study the influence of protein fining agents on proanthocyanidins,
colour and browning potential of white wine. The monomeric flavanols were significantly depleted by casein, and gelatine with low
molecular weight (MW) distribution, and isinglass obtained from fish swim bladder (MW > 94.0, containing some bands in the range
94.0–43.0 and at 20.1 kDa). However, the other gelatines and isinglass with a MW polydispersion below 20.1 kDa did not interact significantly
(P < 0.05) with these compounds. In contrast, the oligomeric compounds were not decreased by swim bladder isinglass. It was
also observed that neither of the isinglasses decreased the polymeric flavanols significantly (P < 0.05). Although casein and potassium
caseinate had similar MW distributions and isoelectric points, potassium caseinate decreased the polymeric flavanols, whereas casein
did decrease monomeric, oligomeric and polymeric flavanols significantly (P < 0.05). The degree of polymerisation of polymeric proanthocyanidins
that remained in the fined wine decreased significantly (P < 0.05) after addition of protein fining agents except when potassium
caseinate was used. Casein, potassium caseinate and swim bladder isinglass induced a significant (P < 0.05) decrease in wine colour
(A420nm), a decrease in browning potential and a decrease in turbidit
Antioxidant activity and phenolic composition of wine spirit resulting from an alternative ageing technology using micro-oxygenation: a preliminary study
Aim: Alternative technologies for the aging of wine spirit, as for other spirit beverages, have been developed over
the past decade in order to meet consumer and industry expectations of differentiation and sustainability.
Physicochemical characterisation of the resulting products has been carried out, but no previous research has
evaluated their antioxidant activity. This preliminary study examined the effect of an alternative ageing technology
(micro-oxygenation combined with wood staves from chestnut or Limousin oak in 1000 L stainless steel tanks) in
comparison with traditional technology (250 L new barrels) on the antioxidant activity and related phenolic
composition of the wine spirit.
Methods and results: The wine spirits resulting from both technologies were sampled after 8, 15, 30, 180 and
365 days of ageing. Samples taken were analysed using the DPPH method, HPLC and total phenolic index.
Significantly higher antioxidant activity (50.43 % vs 36.42 % DPPH inhibition), together with greater enrichment in
wood-derived compounds (51.79 vs 27.72 total phenolic index), was achieved in wine spirits aged using the alternative
technology than in new barrels. Moreover, chestnut wood stood out from Limousin oak wood with higher promoted
antioxidant activity (62.69 % vs 21.35 % DPPH inhibition), and higher phenolic index (49.03 vs 25.67). Significant
correlations between the wine spirits’ antioxidant activity, total phenolic index, ellagic acid, gallic acid, vanillin and
syringaldehyde concentrations were observed, particularly in those aged using the alternative technology.
Conclusion: Micro-oxygenation combined with staves resulted in higher accumulation of bioactive compounds and
antioxidant activity, thus increasing wine spirit quality and adding value to the product.
Significance of the study: These preliminary results show that the characteristics acquired by the wine spirit, coupled
with those revealed by previous research and the promotion of faster and cheaper ageing, make the alternative technology
a promising option for the industryinfo:eu-repo/semantics/publishedVersio
Impact of cherry, acacia and oak chips on red wine phenolic parameters and sensory profile
Aim: The evolution of global phenolic parameters and the sensory profile of a Portuguese red wine aged for 90 days in contact
with wood chips from different species were evaluated.
Methods and results: For this purpose, wood chips from cherry (Prunus avium), acacia (Robinia pseudoacacia) and two oak
species (Quercus petraea and Quercus pyrenaica) were added to a Portuguese red wine. Various global phenolic parameters of
red wines were studied during the aging process (90 storage days). In addition, a sensory analysis was made after the 90-day
aging period to determine the impact of the use of different wood chip species on red wine sensory profile. The results showed
that during the aging period, only a few differences were detected between the wines. However, after 90 aging days, in general
the wines aged in contact with cherry wood tended to have the lowest values for several phenolic parameters. For sensory
parameters, the wine aged in contact with French oak chips showed significantly higher scores for several aroma descriptors,
while for visual and taste descriptors no statistical significant differences were found between the wines.
Conclusion: At the concentration used (3 g wood chips/L wine), the different wood chip species studied had no clear influence
on the evolution of the majority of the red wine phenolic parameters. However, from a sensory point of view, the use of
different wood species induced greater differentiation, especially for aroma descriptors.
Significance and impact of the study: The outcomes of this study would be of practical interest to winemakers and regulatory
institutions since they could improve the knowledge of the impact of alternative wood chip species, namely acacia and cherry,
on red wine qualityinfo:eu-repo/semantics/publishedVersio
Effect of commercial mannoproteins on wine colour and tannins stability
Available at ScienceDirectCommercial 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 AragonĂŞs 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
Effect of Winery Yeast Lees on Touriga Nacional Red Wine Color and Tannin Evolution
Red wine aging on lees is a w inemaking practice u sed to achieve more rounded and less astringent
wines. In two different trials, external yeast lees were added to a red wine and their effects on wine color and
tannin evolution during aging were studied. Results indicated that the addition of yeast lees did not affect color
stabilization during the studied period. Color compounds a nd condensed tannins were rapidly adsorbed to t he
yeast lees at the beginning of the experiment. There was a retarding effect on proanthocyanidin polymerization
reaction by the addition of yeast lees, leading to the maintenance of low and medium molecular weight tannins in
solution. Two different interactions were observed: first, proanthocyanidin adsorption by the yeast lees, primarily
ones with the highest polymerization degree, and second, the retarding of proanthocyanidin polymerization,
likely by the mannoproteins released by yeast lees. The age of the yeast lees was a factor in mannoprotein release
and its effect in wineinfo:eu-repo/semantics/publishedVersio
Use of oak and cherry wood chips during alcoholic fermentation and the maturation process of Rosé wines: impact of phenolic composition and sensory profile
There is a lack of knowledge about the use of di erent wood species on rosé wine production.
Thus, this work focused on the impact of the addition of wood chips from oak and cherry trees during
the alcoholic fermentation and maturation process on rosé wine characteristics. Therefore, phenolic
composition and sensory characteristics were monitored during the rosé wines’ production. The use
of wood chips during alcoholic fermentation induced a significant increase of phenolic content in
rosé musts. During rosé wine maturation, the wood chip contact induced significantly higher values
of colored anthocyanins, color intensity, and polymeric pigments, and significantly lower values of
color hue in the corresponding rosé wines. In terms of sensory profile, a tendency for lower scores of
“overall appreciation” were attributed to control rosé wine, while significantly higher scores for “color
intensity” descriptor were attributed to all rosé wines matured in contact with wood chips. For the
majority of phenolic parameters and individual phenolic compounds quantified, a clear and specific
influence of the use of oak and cherry wood chips was not detected, except for (+)-catechin, where
the rosé wines produced in contact with cherry chips showed the highest values. This study provides
relevant information for winemakers about the impact of the use of wood chips on rosé wine qualityinfo:eu-repo/semantics/publishedVersio
Chemical characterization and antioxidant activities of oligomeric and polymeric procyanidin fractions from grape seeds
Two procyanidin fractions, namely oligomers and polymers isolated from grape seed methanolic extract were characterized. Phenolic
composition and procyanidin purity of these fractions were determined by normal-phase and reverse-phase HPLC, thioacidolysis-HPLC,
ESI-MS analyses, formaldehyde–HCl precipitation and elemental analysis. Antioxidant activities of these fractions and other wellknown
antioxidants were measured using xanthine–xanthine oxidase system for generating superoxide radical ({O
2 }), the DPPH
(1,1-diphenyl-2-picrylhydrazyl) radical method and the Fenton system for generating hydroxyl radical (HO ). The results showed that
both oligomeric and polymeric procyanidin fractions were highly pure, with the degree of polymerization ranging from 2 to 17–18
and 12 to 32–37, respectively. On the basis of molar concentration, polymeric procyanidins appeared the highest antioxidant activities,
followed by oligomeric procyanidins, whereas catechins presented a lower antioxidant activity than its oligomers and polymers. These
results indicate that the antioxidant activities of grape seed procyanidins are positively related to their degree of polymerization. Moreover,
grape seed procyanidins presented higher antioxidant activities than other well-known antioxidants such as vitamin C, suggesting
that grape seed procyanidins might be of interest to be used as alternative antioxidant
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