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.     

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.     

Anthocyanin fingerprint of clones of Tempranillo grapes and wines made with them

Background and Aims:  Different clones with distinctive enological characteristics have been identified in many grape cultivars, but data on differences in anthocyanin composition of clones of the same cultivar are scarce. Thus, it has been considered of interest to check changes in the anthocyanin fingerprint of six different clones of Tempranillo grapes grown in the same vineyard, and of wines made with them, over three consecutive years.
Methods and Results:  Data were submitted to different statistical procedures. Despite slight differences in the anthocyanin fingerprint of some clones (relative content of different anthocyanins analysed), variations from year to year were more important than differences in the anthocyanin profile of the clones considered. This fact was also observed when the content (mg/kg grapes) of those molecules was considered. Moreover, Tempranillo wines made with different clones could be classified by discriminant analysis, using the anthocyanin fingerprint or the levels (mg/L wine) of several anthocyanins as predictor variables, and the year grapes were collected as a classification factor.
Conclusions:  The anthocyanin fingerprint of six clones of Tempranillo grapes grown in the same vineyard and that of wines made with them over three consecutive years was affected mostly by weather conditions, despite slight differences in the anthocyanin fingerprint of some clones.
Significance of the Study:  This is the first report on the anthocyanin composition of different clones of Tempranillo grapes and of wines made with them, and indicates that anthocyanin fingerprint of Tempranillo wines depends mainly on agroclimatic factors, and not on genetic differences among clones.     

Effect of aging in new oak, one-year-used oak, chestnut barrels and bottle on color, phenolics and gustative profile of three monovarietal red wines

This study provides specific information about the influence of storage in bottle and in 225-L barrels made from oak (new and used for 1 year) and chestnut wood on color indexes, spectrophotometric evaluable polyphenols, anthocyanins, phenolic acids and gustative attributes of three monovarietal red wines (Piedirosso, Cabernet Sauvignon and Merlot). The results of the analysis of variance show that wood type has a significant influence on chromatic characteristics, on vanilline reactive flavans, on low molecular weight phenolics and on astringency of wines. The effect depends on the type of wine. Therefore, both traditional and alternative wood containers could be used as an instrument to regulate the polymerization, oxidation and copigmentation reaction of wine phenolics and the sensory properties of red wine. The maturation in chestnut wood could be an interesting challenge to widen the supply of red wines maturated in wood, but its use needs more care than oak.     

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.     

Phenolic and Anthocyanin Profile of Valea Calugareasca Red Wines by HPLC-PDA-MS and MALDI-TOF Analysis

The quality of red wines is given by phenolic compounds and anthocyanins and is associated with colour, taste and therapeutic effects on human health. This work aims to provide a detailed profile of phenolic compounds and anthocyanins that are found in five red wine samples from Dealu Mare-Valea Calugareasca region. The phenolic and anthocyanin profiles of the red wine samples were determined by high-performance liquid chromatography-photodiode array-mass spectrometry and matrix-assisted laser desorption/ionisation–time of flight, respectively. The results obtained showed that Feteasca Neagra had the highest content of phenolic compounds followed by Pinot Noir while the preponderant compound was gallic acid. Amongst anthocyanins, malvidin was found to be the major compound and the highest anthocyanin content was found also for Feteasca Neagra wine. A simple high-performance liquid chromatography-photodiode array-mass spectrometry method was developed, optimised and applied for the quantification of phenolic compounds in red wine samples from Dealu Mare-Valea Calugareasca region. In the same time, a rapid matrix-assisted laser desorption/ionisation–time of flight method that does not need sample preparation was applied for the identification of anthocyanins. Moreover, the phenolic and anthocyanin composition of red wines from Dealu Mare-Valea Calugareasca region is reported for the first time. The phenolic and anthocyanin profile determination will be beneficial for the Romanian winemakers to produce high-quality red wines.     

EFFECTS OF DIFFERENT MACERATION TIMES AND PECTOLYTIC ENZYME ADDITION ON THE ANTHOCYANIN COMPOSITION OF VITIS VINIFERA CV. KALECIK KARASI WINES

Kalecik karasi is an important red grape cultivar for winemaking in Turkey. The effect of three different maceration times (3, 6 and 12 days) and addition of pectolytic enzyme (2 and 4 g/hL) on the anthocyanin and chemical composition of Kalecik karasi wines were studied. High performance liquid chromatography-mass spectrometry coupled with diode array detection was used for analysis. Fourteen anthocyanin compounds were detected in wines. Major anthocyanins in all wines are malvidin-3-glucoside and its acylated esters. The results showed that increasing maceration time, especially with addition of enzymes, gives significant increases in anthocyanin contents. Moreover, the wines treated with enzymes had higher values in total phenolics, tannins, and color intensity than the control wines.

PRACTICAL APPLICATIONS

Anthocyanins are the most important polyphenols in red grapes and red wines with potential health benefits. Therefore, the first analysis of the anthocyanins contents of wine obtained from important turkish cv. Kalecik karasi using liquid-chromatography-mass spectrometry and the influence of different maceration times and addition of pectolytic enzyme on these important phenolic compounds are of interest for scientific literature, the wine industry as well as for the wine consumer.     

中国东亚种红葡萄酒的颜色特征及酚类组成研究

为探究东亚种红葡萄酒的颜色特征以及酚类物质轮廓,采用分光光度法、酶标仪和高效液相色谱-串联质谱（HPLC-MS/MS）技术分别对3款东亚种、3款欧亚种及2款杂交种（山葡萄×欧亚种）红葡萄酒的颜色和酚类物质组成进行分析,并对其花色苷衍生物进行鉴定。结果表明,与欧亚种红葡萄酒相比,东亚种红葡萄酒的辅色花色苷含量较高（55.63%～55.66%）,而聚合花色苷含量较低（19.63%～27.01%）,并且花色苷含量较为丰富（399.30～829.95 mg/L）,以花色素-3,5-O-双葡萄糖苷为主（＞97.50%）,酰化花色苷较低（＜21.78%）。花色苷衍生物检测结果表明,东亚种红葡萄酒中的花色苷与（表）儿茶素聚合产物和吡喃花色苷的含量极低（痕量水平）。东亚种红葡萄酒在非花色苷酚组成上的突出特点为单体和二聚体黄烷醇的含量极低,因此其对酒体颜色的潜在影响可能较小。     

Practical interventions that influence the sensory attributes of red wines related to the phenolic composition of grapes: a review

The phenolic composition of red wines is complex and intimately involved in colour, taste, mouth‐feel and aroma. There have been significant advances in knowledge of compounds with relatively simple structures, but understanding of those with more complex and probably diverse structures is challenging. A number of phenolic compounds may form temporary complexes with anthocyanins and/or be involved in reactions that lead to relatively stable coloured compounds. A wide range of phenolic compounds is implicated in the oral sensory attributes of red wines. Of particular importance are flavan‐3‐ols, including proanthocyanidins (PAs). The generally observed decline in the extractability of PAs during berry ripening is due to binding with cell wall material, which may occur within the developing berry and also from tissues brought into contact during processing. Studies have shown that exposure/reduced vigour results in an increasing proportion of skin PAs being extractable during wine making. Temperature and light influence anthocyanin with temperature probably being more important and the most sensitive stage being 1–3 weeks after véraison. Skin PAs are extracted earlier than those from seeds during wine‐making. Recent results suggest some rearrangement of skin and/or seed PAs occurs during vinification which involves the cleavage of large polymers or the aggregation of small ones. The polymeric material is particularly influential in wine astringency and is transformed by incorporation of anthocyanins into tannin‐like compounds during wine‐making and storage. Although some grape‐derived phenolic compounds contribute to the aroma of red wines, likely of greater importance are the effects of nonvolatile phenolics on the volatility of a diverse range of aroma compounds. Advances in analytical techniques are likely to provide greater insights into the structures and conformations of phenolic polymers and the role of cell wall material in relation to phenolic extraction and reaction during vinification. In relation to aroma, much more research is required to reveal the details of the interactions involving phenolics with volatile compounds. It seems likely that the ability to influence the relative extraction and subsequent reaction of skin and seed phenolics is important in the production of full colour, aromatic and long‐lived wines.     

Phenolic composition and sensory characteristics of Cabernet Sauvignon wines: effect of water stress and harvest date

The effect of three water status level and two harvest date 55 and 64 days after veraison (DAV) on phenolic and sensory composition of Cabernet Sauvignon wines were investigated. The later harvest date led to wine with a higher alcohol content. Total phenols varied from 1439.66 to 1643.08 mg L^?1 with higher values at 64 DAV. No differences were observed between irrigation treatments. For total tannins and anthocyanins, no differences were found between harvest date. Separation of proanthocyanidins by Sep‐Pak Plus tC₁₈ cartridges showed only differences in concentration but not in the proportion of proanthocyanidin fractions. The wines from the most restricted treatment had a better colour and the same aroma of red fruits, persistence, astringency, fullness and bitterness, as the wine from the treatment with highest irrigation. Under the assay conditions, it was possible to obtain wines with a similar chemical and sensory composition earlier and using less irrigation water.     

The impact of high voltage electrical discharge plasma on the chromatic characteristics and phenolic composition of red and white wines

The cold plasma is an emerging electrotechnology for the improvement of food safety without loss of physicochemical or sensory properties. The purpose of this study was to evaluate the effects of plasma treatments on the chromatic characteristics and phenolic composition of red and white wines. The red wine Cabernet Sauvignon and white wine Graševina were treated with high voltage electrical discharge plasma considering the variations in frequency (60, 90 and 120 Hz) and processing time (3, 5 and 10 min). Total phenolics, total anthocyanins, total tannins and chromatic characteristics were analyzed by spectrophotometry while free anthocyanins, phenolic acids and flavan-3-ols by the HPLC-UV/Vis. Obtained results illustrated that plasma treatments have influenced the stability of phenolic compounds in wines without major changes in color parameters. Also, among two different processing parameters, the duration time was the most significant factor inducing changes on wines.Industrial relevanceHigh voltage electrical discharge plasma has been shown to affect the stability of wine phenols without any significant change in the color. An increase in the concentration of certain phenolic compounds in white wine suggest that this technique could be used in the wine industry as an alternative technique for enhancing the oxidative stability of wine and consequently the wine quality during the aging process.     

Bitterness and astringency of grape and wine polyphenols

Extracts containing anthocyanins (ACN), and skin tannins (SKIN) and seed tannins (SEED) were prepared from Vitis vinifera cv. Cabernet Franc grapes grown in the Loire Valley, and characterised. Phenolic fractions from Cabernet Franc wines made from three Loire Valley locations were also isolated and characterised. Bitterness and astringency of ACN, SEED and SKIN as well as the wine extracts were evaluated by time intensity procedures in citric acid solution and in a base white wine. SEED and SKIN were equally astringent when tasted at the same concentration in spite of differences in tannin composition. The lower molecular weight (MW) of SEED was equal in astringency to larger MW SKIN which had a lower percentage of galloylation. The SEED fraction was slightly more bitter than the SKIN fraction in the citric acid solution, although no difference could be detected between samples in base white wine. Astringency of ACN alone was much lower than either SKIN or SEED. Addition of ACN to either tannin fraction produced very small sensory effects in citric acid. In wine, addition of ACN to either SEED or SKIN increased astringency significantly over either fraction alone, but had no effect on bitterness. The wine fractions differed only in astringency, which was correlated with tannin units as determined by thiolysis.     

Effects of mechanical thinning on fruit and wine composition and sensory attributes of Grenache and Tempranillo varieties (Vitis vinifera L.)

Background and Aims: Cost-effective yield control is required by the wine industry in order to reduce the existing worldwide wine surplus and to improve grape quality. The object of this study was to evaluate the chemical and sensory effects on the resulting wines of mechanical cluster thinning performed at different intensities on Grenache, and at different timings (pea size and veraison) on Tempranillo. Methods and Results: The experiments were conducted with a machine harvester in 2007 on two commercial vertical shoot-positioned vineyards in Spain's Rioja region. In both varieties, mechanical thinning was effective in yield reduction and resulted in more ripened fruit, and wines with higher alcohol and pH values, more intense colour and increased phenolic content. Regardless of the thinning intensity, sensory changes were less noticeable in Grenache than in Tempranillo wines. Of the latter, those from vines thinned during veraison were less aromatic and sour, but had increased astringency. Conclusions: Yield management through mechanical thinning induced changes to the chemical composition of fruit and wines as well as to the wines' aroma, taste and mouthfeel. The extent of the sensory implications seems to depend on several factors such as the variety and timing of thinning application. Significance of the Study: This is one of the first studies addressing the effects of mechanical thinning on the sensory properties of the resulting wine and has implications for viticultural management practices.