Influence of Visual Masking Technique on the Assessment of 2 Red Wines by Trained and Consumer Assessors

ABSTRACT:  During sensory evaluation assessments, visual masking techniques are frequently employed to disguise color differences between samples and minimize perceptual bias. Particularly in wine, the impact of these masking techniques on panelist evaluations has not been well studied. The objective of this study was to study the influence of visual masking techniques on the aroma and flavor assessment of 2 red wines and observe the impact of these techniques on trained and consumer sensory panels. Specific masking techniques included (1) blue wine glass/white illumination; (2) clear glass/red illumination; and (3) clear glass/white illumination. Ten panelists were trained to recognize 7 aroma and flavor attributes, while consumer panelists ( n = 80) evaluated attributes and liking. For the trained panel, the visual masking technique affected only perceived spicy flavor of Syrah ( P ≤ 0.05), with the clear glass/red illumination resulting in more intense spicy flavor compared to the other 2 conditions. Principal components analysis showed that for the 2 red wines evaluated by the trained panel, red illumination resulted in higher spicy attributes and perceived astringency while wines served in blue wine glasses were higher in perceived astringency. For the consumer panel, red illumination resulted in wines higher in perceived astringency and blue wine glasses resulted in wines higher in perceived flavor liking. These results indicated that the visual masking techniques may influence both trained and consumer panel evaluation of aroma and flavor attributes of red wine. However, beyond red wine, this study makes the larger point that the choice of masking technique does impact sensory evaluations.     

Factors influencing sensory quality in red wines of the variety Aghiorghitiko (Vitis vinifera L.) from Nemea

Sensory quality in wines from the indigenous Greek cultivar Aghiorghitiko of Nemea, in 2 years, was studied with multivariate modelling. The appearance, aroma and oral attributes were assessed separately using rank-rating in 13 red Nemea wines, dominated (10 of 13) by Aghiorghitiko, and headspace congeners (51) quantified by solid phase microextraction with gas chromatography. Partial least squares regression (PLS) and discriminant PLS studied relationships between sensory data and congeners, viticultural and oenological data, producers and influence of wood maturations, respectively. Principal component analysis (PCA) spaces for aroma (11 attributes; 64% variance, 3 PCs), congeners (51; 72%, 7 PCs) and oral characters (13 attributes; 77%, 3 PCs) showed similarities in product clustering. Modelling showed clear relationships between sensory character and plant density, wood maturation and producer, respectively. Sensory characters in Aghiorghitiko wines were primarily differentiated by oak maturation and producer influences. A part of the results of this work was presented at the Second International Symposium on the Evaluation and Exploitation of Grapes of Corresponding Terroir through Winemaking and Commercialisation of Wines, 1–3 June 2006, Santorini.     

The impact of closure type and storage conditions on the composition, colour and flavour properties of a Riesling and a wooded Chardonnay wine during five years' storage

This paper presents the results from an investigation to assess the development of a Riesling and a wooded Chardonnay wine over five years following the imposition of several treatments at bottling. The wines were bottled under a screw cap closure, two different natural corks, a synthetic closure and in a glass ampoule. In addition, the effect of storage orientation was investigated. The bottled wines were stored under controlled temperature and humidity conditions. Various analyses were carried out on replicate bottles from each treatment, including sulfur dioxide and ascorbic acid concentration, sensory analysis of appearance and aroma attributes, and spectral measures. The largest treatment effect resided with the nature of the closure. Wines sealed with the synthetic closure were relatively oxidised in aroma, brown in colour, and low in sulfur dioxide compared to wines held under the other closures. A struck flint/rubber ( reduced ) aroma was discernible in the wines sealed under the screw caps or in glass ampoules. Wines sealed under natural bark corks in this study showed negligible reduced characters. The bottle orientation during storage under the conditions of this study had little effect on the composition and sensory properties of the wines examined.     

中国进口红葡萄酒香气特征与价格之间的关联分析

葡萄酒样本选择673 款不同价格水平的进口干红葡萄酒。葡萄酒的香气特征采用经过培训的品尝员的感官描述分析得到,而后香气特征采用“葡萄酒香气轮”上的香气标准术语归类。供试葡萄酒香气特征被标准化后被分为12 个香气类别,每一香气特征和香气类别在不同价格区段的出现频率经统计计算得到。结果表明：不同价格区段的进口葡萄酒具有的香气特征有差异,除了＞1 400 元/瓶的葡萄酒之外,其余价格区段的葡萄酒香气特征的出现频率与价格水平之间存在多元线性关系。偏最小二乘回归模型确认了进口干红葡萄酒价格与香气特征之间的数学联系,即来源于陈酿中的香气特征与价格呈正相关,并且确认＞1 400 元/瓶的进口葡萄酒产品属于奢侈品的特例。     

An assessment of the effects of wine volatiles on the perception of taste and astringency in wine

The objective of this work is measuring the effect of different volatile extract compositions on the perception of taste, astringency, global intensity and persistence of wine. Six Spanish wines, two from Chardonnay and four from Tempranillo grapes, all of them showing different chemical and sensory characteristics, were selected. Wines were separated into volatile and non-volatile fractions by solid phase extraction and lyophilisation and further liquid extraction, respectively. Eighteen “reconstituted wines” were prepared, combining different volatile extracts and different non-volatile matrices and adjusting ethanol content to 12% (v/v), and were further described by a specifically trained sensory panel. Taste attributes (sweetness, acidity, bitterness), astringency, aroma intensity, global intensity and persistence were assessed in both, original and “reconstituted” wines by using a numerical category scale. The sensory properties of the original wines were retained by their corresponding “reconstituted samples”. The sensory assessment of the “reconstituted wines” showed that the addition of volatile fruity extracts from white wines brought about a decrease in astringency and bitterness and an increase in sweet perception in all cases. While global intensity and persistence of white wine matrices were also increased, they did not change in red wine matrices, which suggests that the volatile fraction plays only a secondary role in these attributes of red wines. Similarly, the effects of replacing the volatile fraction of a red wine by volatile extracts from other red wines were small and inconsistent, which confirms that taste and astringency are primarily driven by non-volatile molecules in these wines.     

Sensory attribute evolution in bottled young red wines from Rioja Alavesa

The evolution of 19 bottled young red wines from Rioja Alavesa was studied through 9 months. Twenty-four sensory attributes (including appearance, aroma, flavor, taste and mouth-feel) were evaluated at four times (at 1, 3, 5 and 9 months after bottling) by a ten-member panel. Fifteen physicochemical parameters were also analyzed at these four times. Effect of winemaking process (carbonic maceration vs. destemming), and grape variety (only Tempranillo vs. Tempranillo with a white variety) on wine evolution was considered too. Data were analyzed by analysis of variance. Nine sensory attributes changed significantly through the time: red berry aroma and flavor, body, balance, purple hue and color intensity increased, whereas alcoholic aroma and flavor, and astringency decreased. Almost all the physicochemical parameters changed significantly through the time. The winemaking process and the addition of white grapes did not influence sensory and physicochemical evolution.     

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.     

Measuring colour appearance of red wines

This study was designed to assess the colour appearance of different wines. Four wine samples were chosen: table red, oloroso, tawny port and rosé. These wines were poured at different depths in Petri dishes and in cocktail glasses. All samples were assessed by a panel of eight observers in terms of lightness, colourfulness and hue. All samples were also measured using a tele-spectroradiometer and a digital camera. It was found that physical measurements agreed with visual estimates of lightness, colourfulness and hue. There is some discrepancy between observer hue and physical measurement hue for shallow oloroso. This greenish hue was demonstrated in this work as a physical effect. Tele-spectroradiometer and digital camera results can detect this effect and agreed well. The results showed that the digital non-contact measurement method can obtain fast and accurate results for describing colour appearance of liquid food products like wines studied here.     

不同工艺处理对野生猕猴桃酒品质的影响

分别对野生猕猴桃进行清汁、混汁和带皮发酵处理,采用顶空固相微萃取技术对不同酿造工艺野生猕猴桃酒的香气进行富集,用气相色谱-质谱联用技术对其进行定性定量分析,结合酒的基本理化指标和感官评价比较不同工艺处理野生猕猴桃酒的品质。结果表明：混汁发酵和带皮发酵可降低猕猴桃酒的总酸及挥发酸质量浓度,提高pH值,减少VC损失;带皮发酵的香气物质总量显著高于清汁和混汁发酵（P＜0.05）,且酒中的酯类、萜烯类、酮类物质质量浓度相对较高,但酸类物质质量浓度显著降低（P＜0.05）;不同工艺处理酒中特征香气有所差异,其感官香气也各具特色;带皮发酵酒的香气评分较高,猕猴桃品质特征香气突出;且在口感质量、口感浓度、口感纯正度、香气质量、香气浓度、香气纯正度及整体平衡性方面均优于清汁发酵和混汁发酵。因此,带皮发酵工艺可一定程度提高野生猕猴桃酒的品质。     

两种澄清剂对4种鲜葡萄酒的下胶效果分析

选用保香皂土和蛋清作为下胶澄清剂对4种鲜葡萄酒下胶,分析2种下胶澄清剂的下胶量对4种鲜葡萄酒热稳定性及感官质量（包括外观、香气和口感）的影响。结果表明,鲜酒轻柔桃红葡萄酒、鲜酒轻柔红葡萄酒和鲜酒浓甜红葡萄酒选用保香皂土下胶,下胶量为1.0 g/L时,3款葡萄酒的热稳定性均合格且风味物质损失最少,感官评分分别为92、91、93;鲜酒轻柔干红葡萄酒选用蛋清下胶,下胶用量为0.07 g/L时,轻柔干红葡萄酒热稳定性合格且风味物质损失最少,感官评分为93分。     

Consumer acceptability,sensory properties and expert quality judgements of Australian Cabernet Sauvignon and Shiraz wines

Background and Aims: This study aimed to determine what sensory attributes most drive consumer and expert acceptance for Cabernet Sauvignon and Shiraz wines. Methods and Results: The sensory attributes of a set of commercial wines were quantified by a trained panel. A subset was assessed blind for liking by 203 consumers and for quality by 67 winemakers. For the total group of consumers, wines with low levels of ‘bitterness’, ‘hotness’, ‘metallic’, ‘smoky’ and ‘pepper’ were preferred. In addition, four consumer clusters were identified, each with different sensory drivers of preference, with the attributes ‘red berry’, ‘floral’, ‘caramel’ and ‘vanilla’ aroma, ‘acidity’, ‘green’ flavour and astringency being of importance in distinguishing the different clusters' acceptance scores. The winemakers' quality scores had little relationship with consumer response, although both groups gave low ratings to wines with Brettanomyces-related flavour. Conclusions: A relatively small set of sensory attributes were of greatest importance to consumer liking, and these generally dominate varietal differences. Winemakers' quality concepts do not closely align with those of the consumers. Significance of the Study: This study identifies sensory properties of red wines which could be maximised as well as those which should be reduced, allowing producers to better meet consumers' preferences.