Colour stabilization of red wines by microoxygenation treatment before malolactic fermentation

Microoxygenation allows the addition of small, continuous and controlled amounts of oxygen, in order to improve wine quality. Then, the effect of this treatment on colour stabilization and phenolic composition was studied. Four single varietal red wines were elaborated during three consecutive vintages. One part of them was microoxygenated before malolactic fermentation, the other part being maintained in stainless steel tanks without microoxygenation.     

Volatile composition of Bobal red wines subjected to alcoholic/malolactic fermentation with oak chips

The effect of wood, in the form of oak chips, on the volatile composition of Bobal red wines caused by adding oak chips at different stages of the fermentation process has been studied. Aroma compounds were isolated by solid phase extraction (SPE) for subsequent analysis by gas chromatography–mass spectrometry (GC/MS). Bobal control wine was produced according to traditional winemaking processes, without oak chips. Oak chips were added to the rest of the wines at two dose levels (3 and 6 g/L) at different stages of the winemaking process: at one week during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Bobal wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids and ethyl, hexyl and isoamyl acetates than the control wine. A similar, trend was observed for higher alcohols. Higher concentrations of benzene compounds, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF followed by young Bobal oak wines. These results reveal that the point of addition during the winemaking process and the dose level of oak chips used have a significant effect on the volatile composition of Bobal red wines.     

Antioxidant profile of red-single variety wines microoxygenated before malolactic fermentation

The controlled addition of oxygen before malolactic fermentation involves stability of wine colour and an improvement in their organoleptic quality. This study has examined its effect on the “in vitro” antioxidant profile of a variety of Spanish red-single variety wines of different ages. Total antioxidant capacity scavenger activity and the biomarkers of oxidative stress were all analysed. Neither antioxidant capacity, nor scavenger activity were influenced by the microoxygenation. However, the biomarkers of oxidative stress showed some effect of this technique. The controlled addition of small amounts of oxygen produced an increase in the prevention of DNA-damage and seems to decrease the capacity to inhibit lipid peroxidation. The effect on the capacity to protect DNA-damages was statistically significant in the groups of young and one year old wines, where microoxygenated wines showed higher values than their respective control ones. Furthermore, the effect on the prevention of lipid peroxidation was only qualitative, any statistical significant difference was found. A varietal effect was observed in analyzing the results, being Tinta del País wines the most influenced by this technique.     

Micro-oxygenation and oak chip treatments of red wines: Effects on colour-related phenolics,volatile composition and sensory characteristics. Part II: Merlot wines

The character of Merlot wines after the treatments of micro-oxygenation and subsequent chips addition, as regards the colour-related phenolics, volatile composition and sensory characteristics, was studied. An increase in the degree of polymerisation of red pigments and a decrease in the value of the red component of the colour (a^*) and the degree of co-pigmentation were observed. The concentrations of monomeric anthocyanins and anthocyanin-derived pigments, such as hydroxyphenyl-pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts, significantly decreased. With regard to the wine aroma, the micro-oxygenation produced a decrease of some esters, alcohols and benzenic compounds and increased some terpenes and C₁₃-norisoprenoids. With regard to sensorial analysis, micro-oxygenation treatment resulted in higher scores for the red fruit and spicy attributes and caused the presence of new attributes (nutty and sweet fruit). This technique produces a lower level of the typical oak chip aromas (vanilla and woody) in Merlot wines.     

Effect of the prefermentative addition of copigments on the polyphenolic composition of Tempranillo wines after malolactic fermentation

The influence of the prefermentative addition of copigments and different winemaking technologies on the polyphenolic composition of Tempranillo red wines after malolactic fermentation was studied. Six experiments dealing with the prefermentative addition of caffeic acid, rutin, (+) catechin, white grape skin tannin, white grape seed tannin and control wines were realised. Three different winemaking technologies (traditional vinification, prefermentative cold maceration at 6–8 °C and cold soak at 0–2 °C with dry ice) were studied. Prefermentative addition of copigments increases anthocyanin copigmentation reactions and produces wines with a greater colour, a higher anthocyanin concentration, a superior contribution of anthocyanins to the colour of the wine, a superior percentage of tannins polymerised with polysaccharides and less astringency. Cold prefermentative maceration increases the extraction of polyphenols, the anthocyanin copigmentation reactions and the polymerisation reactions between tannins and polysaccharides. The effectiveness of the combination of copigments and prefermentative maceration treatments was demonstrated by the increase of the concentration of the polyphenolic compounds.     

Micro-oxygenation and oak chip treatments of red wines: Effects on colour-related phenolics,volatile composition and sensory characteristics. Part I: Petit Verdot wines

In this paper, the effects of micro-oxygenation before malolactic fermentation and oak chip treatments on Petit Verdot red wines have been evaluated. Our attention was focused on the colour characteristics, the phenolic compounds related to the colour of red wine, the volatile compounds, and the sensory characteristics of the wines. The micro-oxygenation treatment promoted the stabilisation of red wine colour by increasing the formation of colour-related phenolic compounds (higher concentrations of pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts). Red wine aroma quality was improved with the addition of oak chips (eugenol and 4-vinyl-guaiacol concentration increased). Micro-oxygenation treatment resulted in higher scores for the plum/currant and spicy attributes, as well as the appearance of tobacco and nutty notes which were absent in the non-treated wines. Nevertheless, the typical oak chip aromas (vanilla and woody) were observed to a lesser extent in wines obtained by micro-oxygenation.     

Partial characterization of peptides from red wines. Changes during malolactic fermentation and ageing with lees

The peptide fraction of an industrially manufactured red wine has been studied during malolactic fermentation, carried out in stainless-steel tanks or in the barrel and ageing in the barrel, with or without lees, for 12 months. Peptides were fractionated using Sephadex LH-20 and Cosmosil 140 C₁₈-OPN columns, giving two fractions in relation to peptide polarity. The most important changes were detected during malolactic fermentation and during the ageing in barrel with lees. The peptides present in the wine could be glycopeptides from grape or yeast. Most amino acids in the most polar peptides were aspartic acid and/or asparagine, glutamic acid and/or glutamine, serine, glycine, α-alanine and tyrosine and, in the less polar fraction, were glycine, α-alanine and leucine. The amino acid distribution is most different in the most polar fraction, among the studied wines, owing to autolysis and hydrolysis of the polypeptides and proteins.     

Repercussion of the clarification treatment agents before the alcoholic fermentation on volatile composition of white wines

Albariño must was clarified with two fining agents, as bentonite and silica gel. Alcoholic fermentation was carried out at semi-industrial scale, and the concentration of free monoterpenes, norisoprenoids, C₆-alcohols, higher alcohols, fatty acids, ethyl esters, and acetates was then investigated. The use of bentonite allows loss of several volatile compounds compared to wine control. In a second step, the effect of clarification–stabilization treatments with silica gel on aromatic substances was compared in order to study this influence in white wines elaborated from different aromatic varieties (Albariño and Loureira). The results showed that the use of these fining agent plays a significant role in the wine volatile composition.     

The impact of oxygen exposure before and after bottling on the polyphenolic composition of red wines

The impact of moderate oxygen exposure after bottling on wine phenolic composition and colour properties has been investigated on four Grenache red wines showing high and low phenolic contents, obtained by flash release (FR) and traditional soaking (Trad), respectively, and processed with (Mox, 4.6 mg l⁻¹ O₂) or without (noMox) micro-oxygenation. Four oxygen transfer rate (OTR) conditions (0.8, 1.9, 8.0, and 11.9 μl oxygen/bottle/day) were ensured by using synthetic closures with controlled oxygen permeability and storage under controlled atmosphere. Wine phenolic composition and colour were monitored by triplicate analysis of bottles sampled at bottling (T0) and after 5 and 10 months of ageing. Phenolic composition was determined by reverse-phase HPLC-DAD–MS analysis, performed directly on the wines and after phloroglucinolysis for proanthocyanidins. Colour was evaluated by UV–visible spectrophotometry and tristimulus colorimetry. At T0, FR wines contained larger amounts of catechins, proanthocyanidins and hydroxycinnamic acids and slightly lower amounts of anthocyanins than the Trad wines while the Mox wines showed higher levels of some derived pigments, especially carboxypyranoanthocyanins, resulting from reactions of anthocyanins with pyruvate. During ageing, a progressive decrease of proanthocyanidins and hydroxycinnamic acid concentrations was observed, independently of OTR. In contrast, the loss of free SO₂, flavan-3-ol monomers and the conversion rate of anthocyanins to new pigments, especially into sulphite bleaching resistant pigments, increased with OTR levels. Among derived pigments, carboxypyranoanthocyanins levels increased both with micro-oxygenation and with OTR and can be considered as oxidation markers while flavan-3-ol–anthocyanin adducts were formed in larger amounts with lower oxygen exposure.     

Impact of malolactic fermentation on the volatile composition of Turkish Kalecik karası red wines

The effects of spontaneous malolactic fermentation (MLF) and a malolactic starter culture (Oenococcus oeni) on the volatile compounds of Kalecik karas? red wines were investigated. The volatile compounds were extracted using liquid–liquid extraction and quantified by GC–MS–flame ionisation detection. Starter cultures of O. oeni had a positive effect in shortening MLF and producing lower volatile acidity. After MLF, the total volatile compounds increased in both the inoculated wines and the spontaneously fermented wine. Ethyl lactate, diethyl succinate and γ‐butyrolactone increased upon inoculation with cultures of O. oeni strains PN4 and VP41. MLF increased the diacetyl concentration in all Kalecik karas? wines. Strain dependent differences were found in the level of diacetyl, with O. oeni PN4 producing more diacetyl than O. oeni VP41. After MLF, the concentrations of acetoin, 4‐ethylguaicol and 4‐ethylphenol increased in spontaneously fermented wine compared with wines inoculated with O. oeni. Accordingly, the use O. oeni PN4 is recommended for a controlled MLF to produce better quality Kalecik karas? wines. © 2018 The Institute of Brewing & Distilling     

Influence of pH and ethanol on malolactic fermentation and volatile aroma compound composition in white wines

The present study investigated the influences of pH and ethanol on malolactic fermentation (MLF) and the volatile aroma profile of the subsequent white wines from Riesling and Chardonnay inoculated with two different Oenococcus oeni strains. In all cases MLF was induced after completion of alcoholic fermentation (AF). Partial MLF occurred under low pH 3.2 and high alcohol (118.3 g/L) conditions. In the cases with complete MLF, the time required for each strain varied from 13 to 61 days and was dependent on bacterial culture, cultivar and wine parameter. Chemical properties of each wine were determined after AF, complete and partial MLF. The wines showed significant differences in total higher alcohols, esters and acids that are important for the sensory profile and quality of wine. This work demonstrated that the wine matrix as well as the pH and alcohol concentration affects MLF and the final volatile aroma profile. Results indicate that changes in volatile aroma composition are not necessarily related to complete MLF and that partial MLF already has distinct influences on the wine aroma profile of white wines.     

Binding of oak volatile compounds by wine lees during simulation of wine ageing

The retention of wine volatile compounds by wine lees could have an influence on the quality of the product. The aim of this work was to study the binding of wine volatile compounds from oak wood by the wine lees during simulation of wine ageing. The compounds with the most affinity for the lees were eugenol, 4-propylguaiacol, 4-methylguaiacol, furfural and 5-methylfurfural. Lees also bound other compounds important for aroma in aged wine such as oak lactones, although to a lesser degree. Guaiacol and γ-nonalactone were the only compounds studied that were not bound by the lees. Because the lees bind important compounds to wine aroma, ageing red wine in oak barrel in presence of lees could diminish the impact of the aromatic compounds from oak wood on wine aroma.     

The development of esters in filtered and unfiltered wines that have been aged in oak barrels

Esters are quite important for the aroma of aged red wine as they contribute to the fruity complex nature of this wine. This research paper measured the development of esters during maturation of Merlot red wines. These wines had different amounts of turbidity. The wine was aged for 18 months either after filtration with diatomaceous earth or without filtration. Both American and French oak barrel were used for storage. The results obtained showed that the unfiltered wine had a greater concentration of esters at the end of the storage period than the filtered wine. Fatty acid and ethanol esters decreased more than isoamyl acetate, independently of filtration. Ethyl octanoate and ethyl decanoate decreased both in filtered and unfiltered wine. Isoamyl acetate was formed in unfiltered wine and ethyl butyrate and ethyl hexanoate decreased in filtered wine while they remained constant in unfiltered wine.     

Differences in the phenolic composition and sensory profile between red wines aged in oak barrels and wines aged with oak chips

The aim of this study was to evaluate the similarities or differences in the phenolic composition and the sensory characteristics between wines traditionally aged in new French and American barrels for different periods of time, and wines aged for 30 days with different kinds (different geographical origin al toasting degree) of oak chips. This study was carried out with two grape varieties, Mencía and Tinta del País, and in two consecutive vintages. The results obtained indicated that it was not possible to obtain wines aged with chips with sensory characteristics similar to those aged for a long time in new barrels, independently. However, the results showed that the use of oak chips could be a good alternative for elaborating young wines with slight olfactory and gustative wood notes quite similar to wines aged in new barrels for short periods of time (about three months).     

Concentration of volatile compounds in Chardonnay wine fermented in stainless steel tanks and oak barrels

The influence of the type of container used in alcoholic fermentation on the formation of volatile compounds in wine from Chardonnay variety was studied. To do so, must from Chardonnay variety was fermented in both stainless steel tanks and in new Nevers oak barrels. The results obtained showed that wine fermented in barrels had a greater concentration of higher alcohols and esters than wine fermented in tanks. Concentration of isoamyl acetate, ethyl hexanoate, ethyl octanoate and ethyl decanoate was four times higher in wine fermented in oak barrels than in wine fermented in stainless steel tanks. With regard to the concentration of acids, a greater concentration of medium-chain fatty acids (C6:0–C10:0) was noticeable in wine fermented in oak barrels. Given that these acids are toxic for the yeasts, they may be responsible for the slower fermentation rate of wine fermented in oak barrels.     

Anthocyanin pattern of Tempranillo wines during ageing in oak barrels and storage in stainless-steel tanks

The anthocyanin fingerprint of Tempranillo wines made with grapes from two different vineyards of Rioja Alta has been studied by high-performance liquid chroatography during their ageing in oak barrels and their storage in stainless-steel tanks. The data were submitted to multifactorial analysis of variance, taking into account several factors: vineyard, age of wines, type of wine (free run wine and a coupage of free run wine and press wine), and type of container (oak barrels or stainless-steel tanks). The results indicate that both the length of ageing or storage and the vineyard where the grapes were grown affect the anthocyanin fingerprint of wines. The effect of the other two factors (type of wine and type of container) on the anthocyanin fingerprint of wines was quite low, despite the differences observed in several spectrophotometric parameters related to colour and phenolics.     

Impact of using Trepat and Monastrell red grape varieties on the volatile and nitrogen composition during the manufacture of rosé Cava sparkling wines

The impact of using Trepat and Monastrell red grape varieties during the manufacture of rosé sparkling Cava wines on the nitrogen and volatile composition compared to a white Cava manufactured with a blend of typical white grape varieties (Xarello: Macabeo: Parellada) has been investigated. The wines were industrially manufactured in a cellar, and the concentrations of outstanding nitrogen compounds and 23 target volatile compounds belonging to different chemical classes were determined in the base wines and in the corresponding Cava wines after 9, 12, 15 and 18 months of aging on lees. After the application of multivariate statistical analysis, the results showed the large effect of the variety employed in the manufacture of Cavas compared to the changes in wine composition due to the aging time. Depending on the composition, Trepat and White Cava wines were more similar than those manufactured with the variety Monastrell. However, the sensory study showed that the two rosé Cava wines had good sensory attributes and even slightly better foam characteristics than the white ones. The sensory study highlighted for the first time the adequacy of using Monastrell red grape variety to manufacture rosé sparkling wines.     

橡木桶陈酿对红葡萄酒抗氧化性的影响

采用2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）方法动态监测经橡木桶陈酿和未经橡木桶陈酿的红葡萄酒的反应过程,比较在测定其抗氧化活性的反应条件上的差异,从而确定适合检测的最佳反应条件,并分析橡木桶陈酿对红葡萄酒中酚类物质含量和抗氧化活性的影响。结果表明,ABTS方法测定经橡木桶陈酿的红葡萄酒抗氧化活性的最佳反应时间范围是240～280 min,最佳稀释比例范围为1∶100～2∶100,未经橡木桶陈酿的最佳反应时间范围是220～260 min,最佳稀释比例范围是3∶100～4∶100,此条件下各因素与自由基清除率的线性关系R2均＞0.999。试验证明,采用合适的检测方法测定不同陈酿方式酒的抗氧化活性有利于提高检测效率和准确性,经橡木桶陈酿过的红葡萄酒中的酚类物质含量和抗氧化活性更高。