Sensory Quality Of Wine Research Articles

Impact of Training System on Fruit Composition and Sensory Attributes of Syrah in California's Dunnigan Hills

‘Syrah’ vines in the Dunnigan Hills, California were trained to one of three canopy systems [Smart-Dyson (SD); southern sprawl (SS); full sprawl (FS)] over 3 years. The canopy system had little impact on yield components. The SS had the smallest berries in 2005, and in 2006, both SS and FS had the smallest berries. Soluble solids were highest in SS in 2005 and 2006 and lowest in FS in 2006. The SS had the highest berry titratable acidity (TA) in 2005 and 2006, FS had the highest TA in 2004 and the lowest in 2006, and SD had the lowest TA in 2004 and 2005. Color intensity was highest in SS in all 3 years and lowest in SD and FS in 2 of 3 vintages. In 2005, berry anthocyanins were highest in SS and lowest in FS. SD berries had the lowest phenols in all 3 years, with FS fruit having similar values in 2005 and 2006. SS berries had the highest phenols in 2005 and 2006. In 2005, SS wines had the highest blueberry and lavender aromas and lowest pepper and herbal aromas, along with the highest anise and lowest cherry flavors and lowest astringency. Wines from SD and FS were lowest for blueberry aromas and highest for herbal; SD was also lowest for lavender aroma. The FS wines had the highest cherry and lowest anise flavors. In 2006, SS wines were highest for lavender, black pepper, and blackberry aromas and weight. SD wines were equal to SS in blackberry, and highest for blueberry aromas. FS wines were the lowest for black pepper, blueberry, blackberry, and lavender aromas; blueberry, blackberry, and lavender flavors; weight and length; and most astringent. The SD system provided the lowest average maximum cluster temperature throughout the growing season, while the FS system experienced highest maximum cluster temperatures, which occasionally were >45°C. Data suggest that canopy systems that provide some degree of cluster shading with an accompanied reduction in cluster temperatures during the growing season might be beneficial in warm winegrowing regions in terms of improving wine sensory quality.

Levels of histamine and other biogenic amines in high-quality red wines

Biogenic amines in wine may impair sensory wine quality and cause adverse health effects in susceptible individuals. In this study, histamine and other biogenic amines were determined by HPLC after amine derivatisation to dansyl chloride conjugates in 100 selected high-quality red wines made from seven different cultivars. Amine levels varied considerably between different wines. The most abundant amines were putrescine (median = 19.4 mg l−1, range = 2.9–122), histamine (7.2 mg l−1, 0.5–26.9), and tyramine (3.5 mg l−1, 1.1–10.7), whereas lower levels were found for isoamylamine (median = 0.25 mg l−1), phenylethylamine (0.16 mg l−1), cadaverine (0.58 mg l−1), spermidine (1.8 mg l−1) and tryptamine (0.06 mg l−1). Positive correlations were observed between isoamylamine and phenylethylamine, and between histamine, putrescine and tyramine levels. Amine concentrations were similar in all wine cultivars except Pinot noir and St. Laurent wines, which showed significantly higher tryptamine and cadaverine levels. The results indicate that levels of histamine and other biogenic amines may vary considerably between red wines independent of grape variety and that high amounts can also be found in high-rated wines. Adopting a legal histamine threshold level of 10 mg l−1 in the European Union, as formerly introduced in other countries, would have excluded 34% of the investigated wines from the market.

Levels of Histamine and other Biogenic Amines in Red Wines and Sparkling Wines

RATIONALE: Wine intolerance is often considered to be due to histamine and other biogenic amines (BA) present in wine, but not all wines may elicit symptoms to the same extent. We investigated the variability of BA levels in red and sparkling wines and the relationship with grape variety, vintage and wine sensory quality.

Yeast strain effect on the concentration of major volatile compounds and sensory profile of wines from Vitis vinifera var. Treixadura

The fermentative ability of five Saccharomyces cerevisiae strains and their influence on the aroma and sensory properties of wine from Treixadura were evaluated to determine the most suitable yeast that produces a high quality wine from this grapevine variety. The results indicated that all strains, except T2, were able to lead the vinification process and have good fermentative powers. The chemical composition of wines obtained with resident cellar yeasts consisted of a significant amount of glycerol, a compound that contributes to the structure and smoothness in taste of the wine. In addition, these strains were good producers of acetates, ethyl esters and fatty acids, compounds that positively influence wine aroma. Compounds with a direct contribution to the aroma of Treixadura wines (Odour Activity Value >1) included 2-methyl-1-butanol, 3-methyl-1-butanol, 2-phenylethanol, isoamyl and ethyl acetate and the ethyl esters, ethyl butyrate, ethyl hexanoate, ethyl octanoate and ethyl decanoate. Sensory analysis supported the fact that cellar strains produced more fruity and floral wines than commercial or spontaneous fermentations. We conclude that resident cellar yeasts enhanced sensory quality of wines from Treixadura.

Influence of Candida pulcherrima Patagonian strain on alcoholic fermentation behaviour and wine aroma

The use of selected Saccharomyces and non- Saccharomyces strains as mixed starters in winemaking would have advantages over the traditional spontaneous fermentation, producing wines with predictable and desirable characteristics. The aim of this study was to evaluate the impact of metabolic interactions between Patagonian indigenous Saccharomyces cerevisiae MMf9 and β-glucosidase producer Candida pulcherrima V 6 strains on alcoholic fermentation behaviour and wine aroma Three inoculation strategies, simultaneous, sequential and final, were assayed at laboratory-scale fermentations using Muscat d'Alexandrie grape juice as substrate. The fermentation and yeast growth kinetics as well as the physicochemical and the sensory quality of wine were evaluated. Results evidenced that the sequential inoculation is the most adequate strategy of strains combination. The kinetic behaviour of sequential fermentation was similar to a successful spontaneous fermentation and its wine showed differential aromatic quality as evidenced through PC analysis using physicochemical and aromatic composition data. This wine presented the highest total concentration of higher alcohol, esters and terpenols and the strongest fruity and floral aroma.

Willingness to Pay for Sensory Properties in Washington State Red Wines

AbstractIn this article, we evaluate how sensory qualities of wine, such as astringency, bitterness, aroma, and flavor, affect consumers' willingness to pay for wine. In order to accomplish this objective, we utilize data collected from untrained consumers, a trained panel, and laboratory measurements of tannin intensity. From this data, a consumer-preference model, a consumer-intensity model, a trained-panel model, and an instrumental-measurement model are estimated and compared. Overall, the consumer-preference model is the most accurate in predicting consumers' willingness to pay. As expected, the closer a wine is to a consumer's ideal, the more they are willing to pay. Astringency has a mostly positive effect, and bitterness has a negative effect. Comparing the accuracy of the other models, the instrumental-measurement model is the next best, followed by trained-panel model, and the consumer-intensity model. This suggests that the instrumental measurements can be used as an effective alternative to trained panels. This is important because trained panels may be less practical to use on an ongoing basis. (JEL Classification: Q13, M31)

The gap between wine expert ratings and consumer preferences

PurposeExpert wine awards are commonly used by consumers to reduce complexity in wine choice but little is known about expert vs non‐expert perceptions of sensory wine quality. This paper aims to examine if expert ratings are suitable quality indicators for consumers and whether there are certain groups of consumers that find expert awards more useful than others.Design/methodology/approachThe paper compares German consumer ratings obtained in a sensory laboratory with German Agricultural Society's quality competition awards. it tests for the correspondence between expert and non‐expert ratings and for the concordance within the non‐expert group. Estimation of a linear mixed model serves to identify consumer‐side variables with an influence on individual rating distance.FindingsCorrespondence between expert and non‐experts and concordance within the non‐expert group were found to be insignificant. Experienced wine consumers with sufficient specific knowledge and superior self‐reported sensory skills better replicated expert ratings.Research limitations/implicationsWith 216 wine ratings obtained from 36 German consumers, the number of observations is small. Future research should verify above findings by considering more consumers and the stability of ratings across time.Practical implicationsThe findings suggest that although some consumer segments may find expert awards to be useful decision cues, for a large portion of the market, there is demand for a more consumer‐orientated system of sensory quality evaluation and labelling.Originality/valueThis paper is the first to address the usefulness of expert ratings to novice and experienced wine consumer populations. The statistical procedures employed (including linear mixed modelling) are shown to be useful techniques to handle the repeated measurement nature of the data.

Molecular identification of Brettanomyces bruxellensis strains isolated from red wines and volatile phenol production

The spoilage yeast Brettanomyces/Dekkera can persist throughout the winemaking process and has the potential to produce off-flavours that affect the sensory quality of wine. The main objective of this study was to select different strains of Brettanomyces bruxellensis isolated from red wines and to compare their volatile phenol production. From a collection of 63 strains, eight strains of B. bruxellensis were selected for volatile phenol production after the application of molecular techniques such as ISS–PCR, PCR–DGGE and REA–PFGE. All strains showed three large chromosomes of similar size with PFGE. However, unique restriction profiles of the chromosomes were visible after NotI digestion that clearly distinguished the strains. All strains were capable of producing large quantities of 4-ethylphenol and 4-ethylguaiacol from p-coumaric acid and ferulic acid, respectively in synthetic media. However, the diversity among strains for volatile phenol production differed between synthetic media and wine with regard to the maximum production levels of 4-ethylphenol and 4-ethylguaiacol. This study illustrated the diversity of B. bruxellensis strains that occur during winemaking.

Influence of `Novarom G' Pectinase β-glycosidase Enzyme on the Wine Aroma of four White Varieties

Knowledge of the aroma precursors in enology has been fundamental in studying the aromatic potential of grape varieties. These precursors, represented fundamentally by the glycosidically-bound aroma compounds, are present in the grape at higher concentrations than the free or volatile forms. Acid hydrolysis of these precursors is not a viable way to produce significant chemical modifications in terpenes, but enzymatic hydrolysis is the best technique to increase the concentration of the free aroma fraction in wines. As a result, current studies are focused on the use of β-glycosidase enzymes to hydrolyze and release these aroma precursors as a way to improve the characteristics and sensory quality of wines. This work describes the influence that the application of `Novarom G' β-glycosidase enzyme has on the aromatic composition of monovarietal wines from four white varieties: Palomino fino, Sauvignon blanc, Traminer, and Viura. The grapes were cultivated in an experimental vineyard at the IFAPA Centro `Rancho de la Merced' (Jerez de la Frontera). Enzyme-treated wines showed significant differences in comparison to the controls in terms of analytical data: the terpenes and 2-phenylethanol concentrations increased in all varieties. The resulting wines had a more floral and fruity aroma and an improved sensory quality.

ENZYMATIC CHARACTERISTICS OF ALCOHOL ACETYLTRANSFERASE FROMHANSENIASPORA VALBYENSIS, A NON-SACCHAROMYCESYEAST

ABSTRACT Alcohol acetyltransferase (AAT) catalyzing 2-phenylethyl alcohol and acetyl co-enzyme A (acetyl-CoA) to form phenylethyl acetate in Hanseniaspora valbyensis was studied. The enzyme was solubilized from lipid particles using 1% Triton X-100 and then purified by three steps of chromatographic separations with diethylaminoethlyl (DEAE) Sepharose, Sephadex G-75 and Octyl Sepharose, respectively. Its molecular weight was estimated to be about 37 kDa. It was discovered that AAT was most active at pH 7.0 and 30C and was stable between pH 7.0–8.0. But most activity was lost at temperatures above 10C. It was found that AAT was strongly inhibited by heavy metal ions such as Hg2+, Zn2+and Pb2+, slightly stimulated by Mg2+and slightly inhibited by ethylenediamine tetraacetic acid (EDTA) and Mn2+. The Km was 12.7 mM for 2-phenylethyl alcohol and 23.2 mM for isoamyl alcohol. Finally, the enzyme was observed to catalyze the esterification of other alcohols with acetyl-CoA, but have preference for 2-phenylethyl alcohol. PRACTICAL APPLICATIONS Aroma and flavor are affected by the esters that exist in cider. Alcohol acetyltransferase (AAT) can catalyze the formation of esters. Moreover, Saccharomyces cerevisiae and non-Saccharomyces yeast produce diverse esters with different concentration during fermentation. The influence of non-Saccharomyces yeast on the sensory quality of wine and mixed fermentation using different yeasts have been discussed. So, the purification of AAT from Hanseniaspora valbyensis provides an understanding of the formation of esters in non-Saccharomyces yeast.

Physicochemical and sensory quality of wines from red sorrel/roselle (Hibiscus sabdariffa L.) calyces: effects of pretreatments of pectolase and temperature/time

SummaryThe effects of pretreating red sorrel (Hibiscus sabdariffa L.) calyces on the physicochemical and sensory quality of wines were investigated. Sorrel calyces were processed at 60 °C for 3.5 h or 90 °C for 30 min at 0%, 0.5% and 1.0% w/w pectolase addition in fermentation of wines. Significant changes (P < 0.01) in all physicochemical parameters of sorrel wines were found during fermentation, but not (P > 0.05) because of temperature/time effects. Colour (P < 0.01) became redder with pectolase and on storage at 23 °C for 2 months. Significant differences (P < 0.01) were noted in sensory quality for taste and flavour, balance, duration and overall quality. Higher (P < 0.01) overall sensory quality scores were obtained for wines by pretreatment at 90 °C for 30 min (10.44–11.06/20) when compared with wines at 60 °C for 3.5 h (6.88–9.06/20). Colour of wines from 90 °C/30 min was most saturated and red than all wines and had pH 2.57 ± 0.01, 0.43 ± 0.07% citric acid, 10.53 ± 0.53 °Bx and 15.29 ± 0.71% alcohol.

Integration of transcriptomic and metabolic analyses for understanding the global responses of low-temperature winemaking fermentations

Wine produced at low temperature is often considered to have improved sensory qualities. To investigate the effects of temperature on winemaking, the expression patterns during the industrial fermentation process carried out at 13 degrees C and 25 degrees C were compared, and correlated with physiological and biochemical data, including viability, fermentation byproducts and lipid content of the cells. From a total of 535 ORFs that were significantly differentially expressed between the 13 degrees C and 25 degrees C fermentations, two significant transcription programmes were identified. A cold-stress response was expressed at the initial stage of the fermentation, and this was followed by a transcription pattern of upregulated genes concerned with the cell cycle, growth control and maintenance in the middle and late stages of the process at 13 degrees C with respect to 25 degrees C. These expression patterns were correlated with higher cell viability at low temperature. The other relevant transcriptomic difference was that several genes implicated in cytosolic fatty acid synthesis were downregulated, while those involved in mitochondrial short-chain fatty acid synthesis were upregulated in the fermentation process conducted at 13 degrees C with respect to that at 25 degrees C. These transcriptional changes were qualitatively correlated with improved resistance to ethanol and increased production of short-chain (C(4)-C(8)) fatty acids and their corresponding esters at 13 degrees C as compared to 25 degrees C. While this increase of ethyl esters may account in part for the improved sensory quality of wine fermented at 13 degrees C, it is still unclear how the esterification of the short-chain fatty acids takes place. On the basis of its strong upregulation at 13 degrees C, we propose a possible role of IAH1 encoding an esterase/ester synthase in this process.

Determination of Growth and Glycerol Production Kinetics of a Wine Yeast Strain Saccharomyces cerevisiae Kalecik 1 in Different Substrate Media

Glycerol has been known as an important by-product of wine fermentations improving the sensory quality of wine. This study was carried out with an endogenic wine yeast strain Saccharomyces cerevisiae Kalecik 1. The kinetics of growth and glycerol biosynthesis were analysed at various initial concentrations of glucose, fructose, and sucrose in a batch system. Depending on the determined values of Monod constants, glucose (K s = 28.09 g/l) was found as the most suitable substrate for the yeast growth. Initial glucose, fructose and sucrose concentrations necessary for maximum specific yeast growth rate were determined as 175 g, 100 l, and 200 g/l, respectively. The yeast produced glycerol at very high concentrations in fructose medium. Fructose was determined as the most suitable substrate for glycerol production while the strain showed low tendency to use it for growth. S. cerevisiae Kalecik 1 could not produce glycerol below 200 g/l initial sucrose concentration. When natural white grape juice was used as fermentation medium, maximum glycerol concentration and dry weight of the yeast were determined as 9.3 g/l and 11.8 g/l, respectively.

Interactions between Yeast Lees and Wine Polyphenols during Simulation of Wine Aging: I. Analysis of Remnant Polyphenolic Compounds in the Resulting Wines

Wine aging on yeast lees is a traditional enological practice used during the manufacture of wines. This technique has increased in popularity in recent years for the aging of red wines. Although wine polyphenols interact with yeast lees to a limited extent, such interactions have a large effect on the reactivity toward oxygen of wine polyphenolic compounds and yeast lees. Various domains of the yeast cell wall are protected by wine polyphenols from the action of extracellular hydrolytic enzymatic activities. Polysaccharides released during autolysis are thought to exert a significant effect on the sensory qualities of wine. We studied the chemical composition of polyphenolic compounds remaining in solution or adsorbed on yeast lees after various contact times during the simulation of wine aging. The analysis of the remnant polyphenols in the wine indicated that wine polyphenols adsorption on yeast lees follows biphasic kinetics. An initial and rapid fixation is followed by a slow, constant, and saturating fixation that reaches its maximum after about 1 week. Only very few monomeric phenolic compounds remained adsorbed on yeast lees, and no preferential adsorption of low or high polymeric size tannins occurred. The remnant condensed tannins in the wine contained fewer epigallocatechin units than the initial tannins, indicating that polar condensed tannins were preferentially adsorbed on yeast lees. Conversely, the efficiency of anthocyanin adsorption on yeast lees was unrelated to its polarity.

The genetic improvement of grapevine cultivars and wine yeast strains: Novel approaches to the ancient art of winemaking

The widening gap between wine production and wine consumption, the shift of consumer preferences away from basic commodity wine to top quality wine, and the gruelling competition brought about by economic globalisation call for a total revolution in the magical world of wine. In the process of transforming the wine industry from a production-driven industry to a market-orientated enterprise, there is an increasing dependence on, amongst others, biotechnological innovation to launch the wine industry with a quantum leap across the formidable market challenges of the 21st century. Market-orientated designer grape cultivars and wine yeast strains are currently being genetically programmed with surgical precision for the cost-competitive production of high quality grapes and wine with relatively minimal resource inputs and a low environmental impact. With regard to Grapevine Biotechnology, this entails the establishment of stress tolerant and disease resistant varieties of Vitis vinifera with increased productivity, efficiency, sustainability and environmental friendliness, especially regarding improved pest and disease control, water use efficiency and grape quality. With regard to Wine Yeast Biotechnology, the emphasis is on the development of Saccharomyces cerevisiae strains with improved fermentation, processing and biopreservation abilities, and capacities for an increase in the wholesomeness and sensory quality of wine. The successful commercialisation of transgenic grape cultivars and wine yeasts depends on a number of scientific, technical, safety, ethical, legal, economic and marketing factors, and it therefore will be unwise to entertain high expectations in the short term. However, in the light of the phenomenal potential advantages of tailor-made grape varieties and yeast strains, it would be equally self-destructive in the long term if this strategically important “life insurance policy” is not taken out by the wine industry. This overview highlights the most important examples of the way in which V. vinifera grape varieties and S. cerevisiae wine yeast strains are currently being designed with surgical precision on the basis of market demand for the cost-effective, sustainable and environmentally friendly production of healthy, top quality grapes and wine.

Effect of the addition of bentonite to the tirage solution on the nitrogen composition and sensory quality of sparkling wines.

When producing sparkling wines by the traditional method, a small amount of bentonite is added to the tirage solution to help with the flocculation of the yeast. This work studies the effect of this addition on the nitrogen composition and sensory quality of the sparkling wines. Two batches of sparkling wines were industrially produced, one with addition of bentonite to the tirage solution and the other without bentonite addition. Samples were taken at 20, 40, 90, 180, 270 and 365 days of aging with yeast. Total, free amino-, protein- and peptide-nitrogen concentrations were determined and foam properties and sensory quality were evaluated. It was observed that the bentonite retained part of the peptides and proteins and had an adverse effect on the sensory quality of the wine.

Individual and Collective Repuatation Indicators of Wine Quality

A model of hedonic pricing is estimated using U.S. data for premium wines from North America (Napa Valley, Sonoma Valley/County, Oregon, Washington State), Australia, South Africa and Chile. Implicit prices for quality attributes including variety, sensory quality ratings, as well as individual and collective reputation indicators are identified. We focus on the value of wine quality to consumers and how quality indicators influence the willingness to pay for premium wine. A information model, where consumers are assumed to fully rely on sensory quality ratings is compared to a reputation model where collective indicators for wine growing areas and individual indicators for specific wine attributes provide additional information about quality to the consumer. Highly significant estimators for sensory wine quality as well as individual and collective reputation indicators explain price differences of premium wines.

Interactions between anthocyanins and aroma substances in a model system. Effect on the flavor of grape-derived beverages.

Evaluation of the sensory quality of wine or grape-derived beverages led us to study the interactions between flavors and anthocyanins, the colored family of polyphenols. The flavylium cation-ligand complexation, resulting in copigmentation (rise in pigment visible absorption with a concomitant bathochromic shift), was investigated using visible absorption spectroscopy. Sole volatile phenols were found to markedly interact with malvidin-3,5-O-diglucoside. With series of guaiacyl-derived aroma substances, acyl-substituted ligands proved to be better copigments than alkyl-substituted ones. Association constants and 1:1 complex stoichiometry were further determined for several substrates. Decreasing binding to malvin was observed for acetosyringone, syringaldehyde, acetovanillone, vanillin, 3,5-dimethoxyphenol, and 4-ethylguaiacol. Addition of 10% ethanol lowered by one-third the association constants for malvin-ligand couples and for malvidin-3-O-glucoside with acetosyringone and syringaldehyde. The main driving force was ascribed to hydrophobicity, although this study evidenced an influence of the ligand substitution pattern on copigmentation.

Scoring vs. Comparative Rating of Sensory Quality of Wines

SUMMARYOne hundred and fifty wines of different types and regions were scored by 11 experienced judges by two methods (scoring and comparative rating). It was thought that the second method (which included a reference wine) would give more stable and consistent results than the standard method. For some categories of wines the standard method resulted in more stable and consistent responses, but for other categories the reverse is true. For some judges and for some categories of wines the two methods were practically identical. The reactions of the judges to the two methods varied greatly.