Effects of pH,sulphur dioxide,alcohol content,temperature and storage time on colour composition of a young Portuguese red table wine

In a young Portuguese red table wine (Douro Valley) a significant relationship between the colour composition (anthocyanins, polymeric pigment, colour density) and five parameters (pH, SO₂, alcohol, temperature, time of storage) were found. Higher temperature increased the loss of individual and total anthocyanins (as measured fay HPLC) during the ageing, while the wines with higher SO₂ content contained a greater amount of anthocyanins. Malvidin 3-glucoside acetate was the only anthocyanin not affected by the SO₂ content, but its concentration was related with the interaction term (time of storage × SO₂ content). Peonidin and malvidin 3-glucoside-p-coumarate were the two anthocyanins affected by the quadratic term of temperature. Three different groups of equations corresponding to the three different states of the glucoside moiety were found. The polymeric pigment absorbance increases daring conservation and with higher temperature, while the pH and SO₂ content decreased the polymeric pigment formation. The colour density of the experimental wine was related significantly to the changes of the coloured anthocyanins and to the polymeric pigment content.     

超声波处理对黑米酒中酚类物质、颜色及抗氧化性的影响

研究了超声处理对黑米酒中酚类物质、颜色及羟基自由基清除能力的影响。结果显示:超声波处理后黑米酒中总酚含量、总黄酮含量、总花青素含量及清除自由基能力均有不同程度下降,而黑米酒亮度(L*)、红色(a*)及黄色(b*)的颜色特性均有一定程度增加;不同超声条件处理后,黑米酒中总花青素含量与其a*有明显相关性,表明总花青素是黑米酒呈现红色的主体物质;超声处理后黑米酒清除羟自由基的能力与黄酮、花青素等的变化呈明显相关性。上述部分指标的变化与自然熟化过程变化基本一致,表明超声在一定程度上可以起到辅助黑米酒熟化的作用。     

Effect of added sulphur dioxide levels on the fermentation characteristics of strawberry wine

The aim of this study to evaluate the effects of sulphur dioxide (SO₂) on strawberry wine fermentation and on the quality of the final wine product. Major aroma compounds, reducing sugars, ethanol, titratable acid and microflora were analyzed during the fermentation of strawberry wine supplemented with 0–100 mg/L SO₂. As the amount of added SO₂ increased, the consumption of reducing sugars and soluble solids and ethanol production decreased during early fermentation, but increased during late fermentation. During the fermentation process, the concentrations of 2‐phenethanol, isobutanol and isopentanol significantly increased and those of n‐propanol, isoamyl acetate and ethyl lactate decreased with increasing amount of added SO₂. The production of n‐butanol, ethyl acetate and ethyl butyrate was slightly dependent on the amount of added SO₂. Yeast cells were the dominant microbe in the fermenting strawberry pulp, and indigenous bacteria and fungi populations decreased rapidly or disappeared because of their sensitivity to SO₂. It was concluded that 60–80 mg/L SO₂ should be added during strawberry wine fermentations to improve wine quality. Copyright © 2016 The Institute of Brewing & Distilling     

Oak‐matured wines: influence of the characteristics of the barrel on wine colour and sensory characteristics

The influence of oak origin (French or American oak), volume (220, 500 and 1000 l barrels) and age of the barrel (new or used) on the colour and sensory characteristics of a red wine, after 6 months of maturation, was studied. The colour of the wines is characterized by the red, yellow and blue percentages, total polyphenols index, free anthocyanins, polymeric anthocyanins, colour density, hue, tannin content and HCl index. The results of a multivariate analysis of variance showed that colour evolution is faster in small, new American barrels than in large, used barrels or in French barrels. This evolution towards a more stable colour is manifested by a higher content of polymeric anthocyanins, hue and HCl index and lower percentage of red colour. The sensory analysis also reflects these results: the samples obtaining higher scores, at this stage of maturation, are those aged in small, new American barrels. Copyright © 2003 Society of Chemical Industry     

不同酒花对葡萄酒感官品质的影响

为研究酒花对葡萄酒品质的影响,分别添加6个品种酒花（法格、哈拉道、捷克萨滋、卡斯卡特、西楚、西姆科）和4个梯度剂量（0.5 g/L、0.8 g/L、1.0 g/L和1.3 g/L）进行葡萄酒发酵,评价葡萄酒气味、滋味、色泽和口感等感官指标,并结合电子鼻对实验结果进行分析。感官评价结果表明,0.5 g/L西楚酒花葡萄酒气味（92.5分）与0.5 g/L西姆科酒花葡萄酒滋味和口感感官评分较高（86.0分和87.9分）,0.8 g/L法格葡萄酒的色泽呈红宝石色,颜色最清澈透明（90分）。电子鼻检测结果表明,空白对照和捷克萨滋、西姆科和哈拉道、法格和卡斯卡特两两相似度高;西楚与其他5种酒花葡萄酒及空白对照差异较大。实验结果对酒花酿造葡萄酒的工业化生产提供一定的参考。     

Influence of the heterogeneity of grape phenolic maturity on wine composition and quality

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.     

不同酒帽管理方式对干红葡萄酒理化指标和感官质量的影响

以赤霞珠、梅洛为原料制备干红葡萄酒,探究带皮发酵期间压帽法和浸入法两种不同的酒帽管理方式对葡萄酒发酵和其基础理化指标、感官质量的影响。结果表明,采用压帽法、浸入法的组别发酵速率存在差异,发酵终产物总酚含量分别为641.17～836.17 g/L、722.00～883.67 g/L,总花色苷含量分别为130.98～210.70 g/L、172.72～259.45 g/L,b*值（黄化程度）分别为27.52～35.78、35.23～36.77。对于梅洛葡萄酒,浸入法在发酵中后期对提升酒中总酚、总花色苷含量方面发挥重要作用,但这一优势在赤霞珠葡萄浸渍过程中并不明显。感官评价结果表明,浸入法可显著提升赤霞珠葡萄酒口感复杂度和梅洛葡萄酒余味持久度。     

天然木塞对干红葡萄酒品质的影响

对七种天然木塞(分别编号为1#～7#)的综合性能进行研究,通过检测木塞外观质量及物理特性,监测瓶贮期间是否漏酒、胀塞,酒液浸塞高度,瓶内游离氧,酒液中溶解氧、游离SO₂、色度、色调,感官评价等多项指标,分析不同天然木塞的优缺点及对瓶装葡萄酒品质的影响。结果表明,2#木塞表面光洁、端面平整、色泽均一;木塞密封性能2#>7#>6#>5#>4#>3#>1#。2#木塞塞孔径最小、皮孔深度最浅、皮孔条数最少,尺寸误差最小、回弹能力最强,瓶贮36个月后,瓶内顶端空间游离氧最低(0.13 mg/L),酒液中溶解氧最低(0.19 mg/L),游离SO₂最高(14 mg/L),色度最低(5.6),色调最低(0.96),感官品质最高(92分)。因此,2#木塞的性能指标及密封酒液的品质最好。     

Exclusion of sunlight from Shiraz grapes alters wine colour, tannin and sensory properties

The aim of this study was to determine how changes in grape composition brought about by artificial shading (sunlight exclusion) influence wine properties including colour, flavonoid composition and sensory attributes. Prior to flowering, bunches of Shiraz grapes were enclosed in boxes designed to eliminate light without altering bunch temperature and humidity. This artificial bunch shading had little effect on berry ripening and accumulation of sugar but at harvest the shaded bunches had smaller berries and higher seed weight, juice pH and titratable acidity. The amount of anthocyanins in the fruit was not changed significantly but anthocyanin composition in the shaded berries was shifted towards dioxygenated anthocyanins (the glucosides of cyanidin and peonidin derivatives). Shaded fruit had increased seed tannins and decreased skin tannins but the largest relative change in flavonoids was a marked decrease in flavonols in the shaded fruit, similar to previous studies. Wines made from shaded fruit had lower wine colour density, total phenolics, anthocyanins and tannins when the wine was bottled and after ageing for up to three years. Analysis of potential flavour compounds following acid hydrolysis indicated that the wines made from shaded fruit had decreased levels of glycosides of β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). Sensory analysis of the wines indicated no significant difference in aroma attributes but the wines made from shaded fruit were rated lower for astringency, fruit flavour and flavour persistence in-mouth sensory attributes. The results indicate that extreme shading of Shiraz fruit can decrease wine colour, anthocyanins and tannins as well as altering sensory attributes.     

Influence of the elimination and addition of seeds on the colour,phenolic composition and astringency of red wine

Several winemaking techniques have been developed to eliminate seeds to prevent the release of high amounts of very astringent proanthocyanidins, especially when the grapes are unripe. However, there is no scientific information on the effects of this practice. The aim of this paper is to study how the elimination and addition of seeds influence the colour, phenolic composition and astringency of red wine. The elimination of around 80% of the seeds led to a significant decrease of colour intensity and anthocyanin concentration. The addition of seeds originated wines with a greater concentration of total anthocyanin, but did not significantly affect the wine colour. These wines also presented significantly higher levels of proanthocyanidins, a greater proportion of epicatechin-3-gallate, a lower mean degree of polymerization, and, in particular, a drastic increase in astringency. Wines obtained with the elimination of seeds, on the other hand, had exactly the opposite characteristics.     

添加洋葱汁和二氧化硫的赤霞珠红葡萄酒发酵的比较

SO2是葡萄酒酿造广泛使用的抑菌剂和抗氧化剂,由于对人体健康的负面影响,近年来有很多替代品的研究.该研究在赤霞珠红葡萄酒自然发酵和接种发酵中添加洋葱汁(50 g/L)和SO2(60 mg/L),通过测定发酵过程中微生物种群量、主要酿造特性、色度和氧化还原电位的动态变化,比较了洋葱汁和SO2的应用效果.结果表明,接种酵母...     

Influence of sustained deficit irrigation on colour parameters of Cabernet Sauvignon and Shiraz microscale wine fermentations

Background and Aims: This study aimed to explore the influence of sustained deficit irrigation (SDI) on the grape and wine colour parameters of two premium red wine grape varieties grown in the Sunraysia region of South Eastern Australia. Methods and Results: The SDI experiments were conducted during three vintages from 2003 to 2004, 2004 to 2005 and 2005 to 2006 on the Vitis vinfera cultivars Cabernet Sauvignon and Shiraz grafted to 140 Ruggeri (V. berlandieri × V. rupestris) rootstock. The grapevines were drip irrigated providing 100% of estimated ET_c (control) and three graded sustained water deficits (Cabernet Sauvignon 70, 52 and 43% of the control; Shiraz 65, 45 and 34% of the control). Microscale wine fermentations were conducted on grapes from the 2006 harvest to assess wine colour density, wine hue, red pigments, anthocyanins, phenolics and copigmentation products in the wine. Wine anthocyanin and phenolic concentrations for both varieties showed significant increases with increasing intensity of SDI. Conclusion: Increases in wine colour with SDI may result from changes in flavonoid biosynthesis as a result of grapevine responses to water deficit. Alternatively, increases in red wine colour could be caused by changes in chemical properties of the anthocyanins to copigmented or polymeric forms during the winemaking or ageing process. Significance of the Study: The Australian wine industry is currently affected by drought and reduced water allocations resulting in production of wine from grapes exposed to water deficit. Findings from this study provide knowledge to the wine industry as to how sustained deficit irrigation may modify wine colour.     

The effect of Saccharomyces cerevisiae and Saccharomyces bayanus yeast on colour properties and pigment profiles of a Cabernet Sauvignon red wine

Red wine was made from the same batch of Cabernet Sauvignon grapes but with two different yeasts, Saccharomyces cerevisiae (SC) or Saccharomyces bayanus (SB). The colour properties and pigment profiles of SC and SB wines were compared at 8 days and 387 days after yeast inoculation. Grape anthocyanin concentration was found to be lower in SB wines than in SC wines at day 8 and 387, but SB wine exhibited greater wine colour density, a* and b*. The anthocyanin concentration did not correlate with wine colour density. The levels of pigmented polymers and SO₂ non-bleachable pigments were found to be higher in SB wine at day 387, demonstrating that the formation of stable pyranoanthocyanins and pigmented polymers was enhanced by SB yeast. Electrospray mass spectrometry was used for the compositional analysis of pyranoanthocyanins, and direct and ethyl-bridged linked condensation dimers of malvidin 3- O -glucoside (MvG) with flavanols (catechin or epicatechin). The data demonstrated that the formation of acetaldehyde-mediated pigments was enhanced by the use of the SB yeast. The compositional analysis suggested that the differences in colour properties and pigment profiles of SC and SB wines were largely due to the greater production of acetaldehyde-mediated pigments by the use of SB yeast.