Influence of grape composition and origin, yeast strain and spontaneous fermentation on aroma profile of Corvina and Corvinone wines

Variety-specific flavor characteristics in the Shandong region: Interaction between fermentation and variety

Exploring new grape varieties in a specific wine region helps enhance product style diversity. This study investigated the flavor characteristics of Cabernet Sauvignon, Merlot, Dornfelder, and Refosco grapes and their wines in the Shandong region, focusing on how fermentation interacts with these varieties to shape their profiles. Results showed that Dornfelder grapes exhibited significantly higher levels of 26 aroma compounds than other varieties, with total aroma compound concentrations 1.75 to 2.38 times greater. Refosco wines exhibited higher concentrations of certain esters, higher alcohol, and fatty acids following fermentation, further intensifying fruity and fatty-related aromas. Dornfelder and Refosco grapes and wines contained significantly higher levels of anthocyanins than traditional varieties: Cabernet Sauvignon and Merlot. Fermentation compensates for deficiencies in volatiles and phenolic compounds in certain varieties, likely due to the fermentation matrix. This study offers guidance for variety selection in the warm temperate monsoon continental climate, exemplified by Shandong.

Discrimination and characterization of the volatile organic compounds in red and black raspberry wines fermented with different commercial Saccharomyces cerevisiae: An integrated analysis using E-nose, GC-MS, GC-IMS, and multivariate statistical models

This study employed E-nose, GC-MS, and GC-IMS to analyze the volatile organic compounds (VOCs) of red and black raspberry wines fermented by commercial Saccharomyces cerevisiae (X16, RB2, XarOm). Relative odor activity value (ROAV) analysis, orthogonal partial least squares discriminant analysis (OPLS-DA), and random forest (RF) were employed to assess the VOCs and predict key aroma compounds comprehensively. The results revealed that red raspberry wine has a higher ester content (64.18% of total VOC content), while black raspberry wine showcased a significantly higher terpene concentration (13.60%). Moreover, the raspberry wine fermented with X16 yeasts demonstrated the highest contents of esters (64.88%) and alcohols (26.21%). In contrast, the RB2 yeasts displayed a higher level of terpenes (9.56%). The ROAV analysis, OPLS-DA, and RF models predicted 11 key aroma compounds in samples. These findings would provide valuable data for the application of commercial S. cerevisiae in the flavor modulation of raspberry wine.

Extending the Influence of Terroir through the Spontaneous Fermentation of Pinot Noir in the Vineyard: A Case Study of Greystone Vineyard Fermentation

This study investigates the influence of vintage and fermentation environment on the microbial diversity, chemical composition, and volatile profiles of Pinot Noir wines, with a focus on comparing vineyard (outdoor) and winery (indoor) fermentations across two consecutive vintages, 2019 and 2020. Grapes were hand-harvested from a single vineyard and subjected to spontaneous fermentations in three tanks for each fermentation environment. Nonmetric multidimensional scaling (NMDS) and PERMANOVA analyses revealed significant differences in fungal community composition between fermentation environments and vintages. Vineyard fermentations consistently exhibited higher levels of non-Saccharomyces yeasts during fermentation, which contributed to increased production of microbial-derived esters, such as hexyl acetate and isobutyl acetate. Winery fermentations, in contrast, showed higher concentrations of anthocyanins, contributing to enhanced color intensity and stability. Vintage effects were more evident than fermentation environment, with the 2019 vintage favoring higher concentrations of phenolics, anthocyanins, higher alcohols (e.g. isoamyl alcohol), and volatile phenols (e.g. guaiacol and eugenol), while the 2020 vintage enhanced the retention of esters and floral terpenes (e.g. linalool). These findings highlight the distinct wine styles achievable through vineyard and winery fermentations, as well as the interplay between climatic conditions and fermentation environment. This work provides novel insights into the potential of vineyard fermentations for expressing microbial terroir and offers practical strategies for optimizing wine production under varying climatic and site-specific conditions.

From microbial communities to aroma profiles: A comparative study of spontaneous fermentation in merlot and cabernet sauvignon wines

This study aimed to compare the microbial community composition and aroma characteristics during the fermentation of different grape cultivars, Merlot and Cabernet Sauvignon. Principal Component Analysis (PCA), Partial Least Squares Discriminant Analysis (PLS-DA), and Odor Activity Value (OAV) screening identified 15 distinct active compounds. The sensory evaluation indicated that Merlot wine exhibited a more intense fruity aroma and received higher overall scores than Cabernet Sauvignon wine. High-throughput sequencing (HTS) results revealed that the microbial diversity in Merlot was higher than in Cabernet Sauvignon wine. Lachancea, Acremonium, Fructobacillus, and Lactiplantibacillus were unique to the Merlot wine, whereas Penicillium, Wickerhamomyces, Gluconobacter, and Klebsiella were exclusive to Cabernet Sauvignon wine. Saccharomyces and Tatumella were identified as the dominant microorganisms during the fermentation of both Merlot and Cabernet Sauvignon wines. Correlation analysis demonstrated a significant positive association among the dominant microbial communities, which played a crucial role in determining the formation of volatile compounds.

Co-evolutionary dynamics of microbial communities and flavor profiles during natural fermentation of Cabernet Sauvignon and Merlot: A comparative study within a single vineyard

Indigenous microorganisms play a crucial role in determining the quality of naturally fermented wines. However, the impact of grape cultivar specificity on microbial composition is often overshadowed by the geographical location of the vineyard, leading to underestimation of its role in natural wine fermentation. Therefore, this study focuses on different grape cultivars within a single vineyard. The physicochemical results revealed that during fermentation of Merlot and Cabernet Sauvignon wines, ethanol content significantly increased, while residual sugar, pH, malic acid, citric acid, and yeast assimilable nitrogen notably decreased. High-throughput sequencing (HTS) results showed that fungal diversity and richness in Merlot were significantly higher than in Cabernet Sauvignon, whereas bacterial diversity exhibited the opposite trend. The predominant fungal genera in Merlot were Hanseniaspora, followed by Lachancea, whereas the opposite was observed in Cabernet Sauvignon. Erysiphe and Pantoea were exclusively present in Merlot, whereas Erwinia was detected only in Cabernet Sauvignon. A total of 106 flavor compounds were quantified using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), identifying 22 core volatile compounds in Merlot and 19 in Cabernet Sauvignon. Moreover, at the end of fermentation, the total ester content in Cabernet Sauvignon was significantly higher than in Merlot, imparting a more pronounced fruity and floral aroma, which was further confirmed using sensory analysis. Correlation analysis indicated that Saccharomyces was positively correlated with alcohol content, total acidity, and 16 core volatile compounds, while Hanseniaspora and Lachancea showed opposite correlations. These insights provide a data reference for producing high-quality wines with regional characteristics.

A comprehensive study on fermentation and aroma contributions of Torulaspora delbrueckii in diverse wine varieties: Insights from pure and co-fermentation studies

As a well-commercialized and utilized non-Saccharomyces yeast, Torulaspora delbruineckii is gaining increasing relevance in the winemaking industry. However, its ability to produce distinctive aromas in wine has been inconsistently reported in the literature. This study aimed to evaluate the fermentation performance and aroma properties of T. delbrueckii isolates through pure and co-fermentation with Saccharomyces cerevisiae across eight different wine varieties: Merlot, Zidaifu, Petit Verdot, Marselan, Italian Riesling, Sauvignon Blanc, Ugni Blanc, and Petit Manseng. A comprehensive analysis using HS-SPME-GC-MS, OPLS-DA, and Spearman's correlation analysis was conducted. Key findings include: (1) The strain T. delbrueckii R12 exhibited higher extracellular enzyme activity compared to S. cerevisiae CECA and demonstrated superior sugar tolerance compared to six other native T. delbrueckii strains. (2) T. delbrueckii R12 exhibited strong fermentative capability, completing fermentation in 23 days across the eight wines, producing lower levels of acetic acid (0 ∼ 0.8 g/L reduction) and ethanol (0.1 ∼ 4.0 % v/v reduction), and higher levels of glycerol (0.1 ∼ 0.9 g/L increase) in the majority of wines. (3) Co-fermentation with T. delbrueckii and S. cerevisiae altered glycosidase activity, enhancing the varietal aroma intensity and complexity of the eight wines by releasing C6 compounds, terpenes and esters, and reducing higher alcohols and fatty acids. (4) The aroma contribution of T. delbrueckii R12 was variety-dependent, with isobutyl alcohol, isopentyl alcohol, 1-pentanol, and 1-propanol prevalent in red wines, and (Z)-2-hexen-1-ol more associated with white wines. Additionally, T. delbrueckii R12 consistently enhanced aromas in all eight experimental wines by increasing levels of 1-hexanol, farnesyl alcohol, linalool, citronellol, ethyl acetate, isobutyric acid and decanoic acid, while decreasing 1-pentanol, octanoic acid, isoamyl acetate, and ethyl laurate. Seven of the increased compounds were identified as signature aromas of T. delbrueckii R12, potentially contributing grass, floral, muscat, rose, fruit, caramel and buttery notes to the wines. This study confirms the significant role of T. delbrueckii in winemaking and wine aroma, resolving previous discrepancies in the literature. It provides new knowledge for innovating and diversifying wine production across various grape varieties.

Dimethyl Sulfide (DMS) in Amarone Wines: Influence of Aging, Withering, Grape Variety, and Geographical Origin

Occurrence of dimethyl sulfide (DMS), a potent aroma compound accumulating during aging, was investigated in commercial and experimental Amarone wines. In commercial Amarone, DMS was observed in concentrations ranging from 2.9 to 64.3 μg/L. Model aging studies on experimental wines indicated that DMS in Amarone is strongly associated with aging and that wines from different vineyards can vary significantly in their ability to accumulate DMS during aging. The capacity of certain vineyards to give wines with higher DMS-forming potential was consistent across three consecutive vintages, representing a true terroir factor to be expressed with aging. Wine content of primary amino acids (PAN), a commonly analyzed enological parameter of grape must, was shown to be positively correlated with DMS accumulation during aging. Grape withering also increased DMS-forming potential mostly due to increased PAN resulting from concentration due to water loss. Increased pH due to withering also contributed to a higher DMS content of withered wines, but to a lower extent. In certain vineyard sites, an influence of vintage conditions on DMS-forming potential was also observed.

A Targeted and an Untargeted Metabolomics Approach to the Volatile Aroma Profile of Young 'Maraština' Wines

This study investigated the detailed volatile aroma profile of young white wines of Maraština, Vitis Vinifera L., produced by spontaneous fermentation. The wines were produced from 10 vineyards located in two Dalmatian subregions (Northern Dalmatia and Central and Southern Dalmatia). Volatile compounds from the wine samples were isolated by solid-phase extraction (SPE) and analyzed by an untargeted approach using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC/TOF-MS) and a targeted approach by gas chromatography-tandem mass spectrometry (GC-MS/MS). A comprehensive two-dimensional GC×GC analysis detailed the total volatile metabolites in the wines due to its excellent separation ability. More than 900 compounds were detected after untargeted profiling; 188 of them were identified or tentatively identified. A total of 56 volatile compounds were identified and quantified using GC-MS/MS analysis. The predominant classes in Maraština wines were acids, esters, and alcohols. The key odorants with odor activity values higher than one were β-damascenone, ethyl caprylate, ethyl isovalerate, ethyl 2-methylbutyrate, ethyl caproate, isopentyl acetate, ethyl butyrate, and phenylacetaldehyde. The metabolomics approach can provide a large amount of information and can help to anticipate variation in wines or change winemaking procedures.

Chemical Composition and Polyphenolic Compounds of Red Wines: Their Antioxidant Activities and Effects on Human Health—A Review

Red wine, an alcoholic beverage is composed of a spectrum of complex compounds such as water, alcohol, glycerol, organic acid, carbohydrates, polyphenols, and minerals as well as volatile compounds. Major factors that affect the levels of phenolic compounds in red wines are the variety of grapes and the storage of the wines. Among the constituents of red wine, phenolic compounds play a crucial role in attributes including color and mouthfeel and confer beneficial properties on health. Most importantly, phenolic compounds such as flavanols, flavonols, flavanones, flavones, tannins, anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and resveratrol can prevent the development of cardiovascular diseases, cancers, diabetes, inflammation, and some other chronic diseases.

Volatile Compounds in Monovarietal Wines of Two Amarone Della Valpolicella Terroirs: Chemical and Sensory Impact of Grape Variety and Origin, Yeast Strain and Spontaneous Fermentation

Aroma profiles of withered Corvina and Corvinone wines from two different Valpolicella terroirs were investigated in relationship to yeast strain and use of spontaneous fermentation. The results indicated that volatile chemical differences between wines were mainly driven by grape origin, which was associated with distinctive compositional profiles. Wine content in terpenes, norisoprenoids, benzenoids and C₆ alcohols, as well as some fermentative esters, were indeed significantly affected by grape origin. Conversely, yeast strain influence was mainly associated with fermentation-derived esters. Sensory analysis, besides confirming the major role of grape origin as driver of wine differentiation, indicated that spontaneous fermentations reduced the sensory differences associated with grape origin and variety, mainly due to high content of acetic acid and ethyl acetate.

Two Sides to One Story-Aroma Chemical and Sensory Signature of Lugana and Verdicchio Wines

Lugana and Verdicchio are two Italian white wines with a Protected Designation of Origin (PDO) label. These two wine types are produced in different regions using the same grape variety. The aim of this work is to investigate the existence of volatile chemical markers that could help to elucidate differences between Lugana and Verdicchio wines both at chemical and sensory levels. Thirteen commercial wine samples were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS), and 76 volatile compounds were identified and quantified. Verdicchio and Lugana had been differentiated on the basis of 19 free and glycosidically bound compounds belonging to the chemical classes of terpenes, benzenoids, higher alcohols, C₆ alcohols and norisoprenoids. Samples were assessed by means of a sorting task sensory analysis, resulting in two clusters formed. These results suggested the existence of 2 product types with specific sensory spaces that can be related, to a good extend, to Verdicchio and Lugana wines. Cluster 1 was composed of six wines, 4 of which were Lugana, while Cluster 2 was formed of 7 wines, 5 of which were Verdicchio. The first cluster was described as “fruity”, and “fresh/minty”, while the second as “fermentative” and “spicy”. An attempt was made to relate analytical and sensory data, the results showed that damascenone and the sum of 3 of esters the ethyl hexanoate, ethyl octanoate and isoamyl acetate, was characterizing Cluster 1. These results highlighted the primary importance of geographical origin to the volatile composition and perceived aroma of Lugana and Verdicchio wines.