Burgundy red wines: Representation of potential for aging

The importance of outlier rejection and significant explanatory variable selection for pinot noir wine soft sensor development

Sensory attributes are essential factors in determining the quality of wines. However, it can be challenging for consumers, even experts, to differentiate and quantify wines' sensory attributes for quality control. Soft sensors based on rapid chemical analysis offer a potential solution to overcome this challenge. However, the current limitation in developing soft sensors for wines is the need for a significant number of input parameters, at least 12, necessitating costly and time-consuming analyses. While such a comprehensive approach provides high accuracy in sensory quality mapping, the expensive and time-consuming studies required do not lend themselves to the industry's routine quality control activities. In this work, Box plots, Tucker-1 plots, and Principal Component Analysis (PCA) score plots were used to deal with output data (sensory attributes) to improve the model quality. More importantly, this work has identified that the number of analyses required to fully quantify by regression models and qualify by classification models can be significantly reduced. Based on regression models, only four key chemical parameters (total flavanols, total tannins, A_520nm^HCl, and pH) were required to accurately predict 35 sensory attributes of a wine with R² values above 0.6 simultaneously. In addition, for classification models to accurately predict 35 sensory attributes of a wine at once with prediction accuracy above 70%, only four key chemical parameters (A_280nm^HCl, A_520nm^HCl, chemical age and pH) were required. These models with reduced chemical parameters complement each other in sensory quality mapping and provide acceptable accuracy. The application of the soft sensor based on these reduced sets of key chemical parameters translated to a potential reduction in analytical cost and labour cost of 56% for the regression model and 83% for the classification model, respectively, making these models suitable for routine quality control use.

Phenolic Characterization of Cabernet Sauvignon Wines From Different Geographical Indications of Mendoza, Argentina: Effects of Plant Material and Environment

The chemical and sensory characteristics of the wines are related to the geographical origin of the grape, as a result of the interplay between the plant material (G), its acclimatization to the environment (E) and the human factor that influences both the vineyard and the winery. The range of phenotypes that a single genotype can express depending on its environment is known as phenotypic plasticity and is the result of G × E interaction. The present study evaluated the independent and interactive effects of Cabernet Sauvignon plant materials (G: Clone 7 and Mount Eden) implanted in different geographical indications of Mendoza, Argentina (E: Agrelo, Pampa El Cepillo, Altamira and Gualtallary) according to fruit yield and phenolic profiles of wines. The experiment was carried out during 2018 and 2019 vintages using a multifactorial design. When berries reached 24 °Brix, the clusters were harvested, analyzed and wines elaborated by a standardized procedure. Then, the anthocyanin and non-anthocyanin phenolic profiles of wines were determined by high-performance liquid chromatography with diode array and fluorescence detection (HPLC-DAD–FLD). The results revealed significant G × E interactions for yield traits, including the number of clusters per plant. Differential chemical composition and quality parameters of the resulting wines, markedly affected by E, were observed; that is the geographical location of the vineyards. There were similarities in the phenolic composition between Pampa El Cepillo and Altamira, while larger differences between Agrelo and Gualtallary were observed. Gualtallary presented the highest levels of anthocyanins, quercetin and trans-resveratrol. The increased amount of these compounds in Gualtallary was associated with an increased UV-B exposure of plants at this high altitude environment. This is the first report that characterizes the effects of plant material and environment for Cabernet Sauvignon. These results are of oenological and viticulture interest for the wine industry demonstrating that the selection of the plant material and the vineyard location for Cabernet Sauvignon can considerably affect the quality attributes of wines.

The Sensory Space of Wines: From Concept to Evaluation and Description. A Review

The concept of sensory space was first formulated over 25 years ago and has been widely adopted in oenology for around the last 15 years. It is based on both the common organoleptic characteristics of products and the mental representations built by specific groups of people. Exploring this concept involves first assessing whether it already exists for tasters, and, when this is the case, conducting perceptual evaluations to verify its effectiveness before potentially highlighting the associated sensory properties. The goal of this review, which focuses on applications linked to the field of oenology, is to study how these three steps are carried out, how the corresponding tasks and tests are performed and managed, and the type of results that can be obtained.

Wine Polyphenol Content and Its Influence on Wine Quality and Properties: A Review

Wine is one of the most consumed beverages around the world. It is composed of alcohols, sugars, acids, minerals, proteins and other compounds, such as organic acids and volatile and phenolic compounds (also called polyphenols). Polyphenols have been shown to be highly related to both (i) wine quality (color, flavor, and taste) and (ii) health-promoting properties (antioxidant and cardioprotective among others). Polyphenols can be grouped into two big families: (i) Flavonoids, including anthocyanidins, flavonols, flavanols, hydrolysable and condensed tannins, flavanones, flavones and chalcones; and (ii) Non-flavonoids, including hydroxycinnamic acids, hydroxybenzoic acids, stilbenes, tyrosol and hydroxytyrosol. Each group affects in some way the different properties of wine to a greater or a lesser extent. For that reason, the phenolic composition can be managed to obtain singular wines with specific, desirable characteristics. The current review presents a summary of the ways in which the phenolic composition of wine can be modulated, including (a) invariable factors such as variety, field management or climatic conditions; (b) pre-fermentative strategies such as maceration, thermovinification and pulsed electric field; (c) fermentative strategies such as the use of different yeasts and bacteria; and (d) post-fermentative strategies such as maceration, fining agents and aging. Finally, the different extraction methods and analytical techniques used for polyphenol detection and quantification have been also reviewed.

Aging of Malbec wines from Mendoza and California: Evolution of phenolic and elemental composition

This work aimed to investigate the evolution of phenolic compounds and elements during the aging of Malbec red wines from different regions of Mendoza (Argentina) and California (United States). The profiles of low molecular weight polyphenols and anthocyanins were analyzed using high-performance liquid chromatography with a diode-array detector (HPLC-DAD), and the elemental composition using microwave plasma-Atomic emission spectrometry (MP-AES). Through uni- and multivariate statistical analyses, the effects of aging time and region on wine were investigated. It was observed that aging time was a significant factor that affected the phenolic compound profile in the studied Malbec wines studied and that after five years of aging, the wines could be differentiated according to region. The results of this study may impact decisions made regarding the storage of Malbec wines in the future.

Evaluation of the impact of initial red wine composition on changes in color and anthocyanin content during bottle storage

Sixteen commercial red wines, selected to cover a different range of color and total polyphenols index (TPI), were stored at 25°C during 6months under controlled and different oxygen additions (0, 1.1, 3.1, 10.6 and 30.4mgL(-1)) during the bottling process. Changes in color and the anthocyanic composition were evaluated using transmittance spectra and UPLC-MS-UV/Vis respectively. Results reveal a general pattern in the evolution of wines. However, different patterns of evolution related to initial wine composition, especially to TPI, were observed. Wines with higher TPI had a lower evolution, whereas wines with lower TPI showed a higher evolution and greater variability in behavior. In general, oxygen seemed to accelerate all changes observed during aging although the oxygen effect was more limited than the effect of the storage time. These results are relevant for wine experts and help explain the evolution of wine at the bottling stage.

Analytical phenolic composition and sensory assessment of selected rare Greek cultivars after extended bottle ageing

BACKGROUND

The Hellenic vineyard embraces a large number of native cultivars, which are mostly unexploited for their ageing potential. Therefore, it was thought that analyzing some quality parameters of 14 red wines produced by rare native varieties would be of great importance in obtaining a general picture of their potential for commercial use. Various analytical methods were applied to the selected wines, at bottling and after 8 years of ageing, in an attempt to provide reliable answers to this issue. In addition, it was of interest to investigate the alteration of the phenolic content and color parameters of the wines after extended bottle storage and to evaluate the overall changes with respect to their sensory properties.

RESULTS

Most of the oligomeric phenolic compounds identified in the wines studied diminished after 8 years of bottle storage, while significant correlations were obtained between wine chemical composition and sensory data.

CONCLUSIONS

After 8 years of bottle storage some of the unexploited varieties (Vitis vinifera) were found to be worthy of further study and use for the production of quality wines. Wines with the best sensory characteristics were those made by Limniona, Mavrotragano, Bakouri, Thrapsa and Mavrothiriko, in accordance (more or less) with the results of chemical analyses.

Role of 3-methyl-2,4-nonanedione in the flavor of aged red wines

GC-MS in chemical ionization mode (CI) was used as a simple, sensitive method for assaying 3-methyl-2,4-nonanedione (MND) in 67 red wines. MND content was shown to be lower in nonoxidized red wines and higher in oxidized red wines, that is, systematically exceeding the perception threshold (62 ng/L). Concentrations up to 340 ng/L in the most oxidized red wines were also evidenced. According to these quantitative data, the presence of MND alone was shown to modify significantly the flavor of the red wine as evaluated from fresh fruit flavor in red wine without MND to aromatic expression of rancio in wines with elevated concentrations (308.9 ng/L). Incidence of oxygen on its formation was also investigated. For the first time, elevated concentrations of this compound in various wines were demonstrated, that is, white, rosé, botrytized wines, and fortified wines made with over-ripened grapes. The lowest levels (2.9 ng/L) were found in nonoxidized white wines, whereas the highest levels were found in oxidized botrytized wines (293.8 ng/L). These results tend to demonstrate that MND is in general a good marker of oxidation in wines made with a maceration step between the skin and the pulp. These preliminary results provide a new analytical explanation of what is known in enology as the "vin de garde" concept.