Varietal Aroma Research Articles

Comparative study of different commercial enzymes on release of glycosylated volatile compounds in white grapes using SPE/GC–MS

Glycosides represent a large source of potential flavor in grape must. Commercial preparations enzymes with glycosidase activity are commonly employed to enhance wine aroma. In this study, we conducted an evaluation of twelve commercial enzymes to assess their effectiveness in releasing volatile compounds from their conjugated forms in a white grape must under laboratory conditions by solid-liquid extraction (SPE) and gas chromatography–mass spectrometry (GC–MS). In this laboratory-level experiment, regardless of the enzymes used, the total concentration of volatile compounds was not statistically affected by the treatments. While the total concentration of volatile compounds remained largely unchanged, four specific volatile groups were significantly affected by the enzyme treatments: acids, alcohols, C13-norisoprenoids, and terpenes. The results also revealed a significant effect of commercial enzymes on individual compounds, which led to a notable increase in the concentration of twenty-one aroma compounds, mainly terpenes. Rapidase Revelation Aroma and Enozym Extra Aroma emerged as the most powerful ones on the must's volatile composition with important ability to release higher concentrations of essential varietal aroma compounds, particularly terpenes and C13-norisoprenoids.

Enhancing variety aromatic characteristics of Muscat wine through cold maceration with indigenous cryotolerant Metschnikowia pulcherrima Mp0520

Cold maceration (CM) is widely applied in winemaking to improve wine aroma and overall quality. However, more efficient CM techniques for industrial-scale winemaking are still needed. This study examined the impact of CM with indigenous cryotolerant Metschnikowia pulcherrima Mp0520 (Mp-CM) on the Muscat wine aromatic characteristics. The results demonstrated a significant divergence in the types and concentrations of aroma compounds between Mp-CM wine and the control. The Mp-CM wine exhibited a significantly higher terpenes content, resulting in a Muscat wine characterized by terpenes, compared to the control predominated by esters. Additionally, the Mp-CM wine demonstrated elevated levels of α-terpineol and terpinolene, potentially enhancing the varietal aroma stability of Muscat wine. Furthermore, Mp-CM gave Muscat wine a heightened fruity aroma and a more complex aroma. These findings suggested that the Mp-CM utilized in this study offered promising avenues for enhancing the variety aroma characteristics of Muscat wine on large scale winemaking.

Impact of Different Wood Types on the Chemical Composition and Sensory Profile of Aged Tsipouro: A Comparative Study

The production of high-quality aged marc spirits includes a minimum period of six months of ageing in oak barrels. Lastly, producers are interested in alternative botanical origin wood. The present study is aimed at investigating the influence of Greek oak (Quercus trojana) and Greek chestnut (Castanea sativa) compared with French (Quercus petraia) and American oak (Quercus alba) on the chemical composition and sensorial characteristics of aged tsipouro, produced from marc from the Black Muscat variety. Gas chromatography–olfactometry–mass spectrometry (GC–O–MS) was used to identify volatile compounds of the aged tsipouro. Also, colour and polyphenol measurements were made, and an organoleptic evaluation was performed by 16 trained tasters. The findings revealed rather similar results between the tsipouro made from different wood species, especially between Greek and French oaks, and relative differentiation for that of chestnut. All the aged distillates exhibited a pleasant and rich aromatic potential, dominated by floral and fruity terpene varietal aromas as well as wood-related volatiles. Chestnut, with a high phenolic potential, gives pleasant organoleptic effects over time and can be an alternative wood for ageing spirits. This research highlights the importance of wood selection in the tsipouro ageing process and enables the use of Greek wood species in the ageing of spirits.

Postharvest dehydration of red grapes: impact of temperature and water-loss conditions on free and glycosylated volatile metabolites of exocarp and epicarp of Nebbiolo and Aleatico varieties.

Postharvest dehydration affects the metabolism of grapes, impacting odorous secondary metabolites and therefore the features of the corresponding passito wines - high-quality products with winemaking practices linked to specific territories and related autochthonous grape varieties. Water loss and temperature conditions are the main variables of the dehydration process. This study assessed how they impacted the patterns of free and glycosylated volatile organic compounds (VOCs) of the exocarp (pulp) and epicarp (skin) in Nebbiolo and Aleatico, a neutral and semi-aromatic red grape variety, respectively. Dehydration parameters were set in tunnel conditions, and VOCs were quantitatively analyzed by solid phase extraction-gas chromatography-mass spectrometry. For Nebbiolo grapes, weight loss had a greater impact on free volatiles than dehydration temperature, with a 20% weight loss increasing total VOCs in both exocarp and epicarp. Low temperature (10 °C) significantly increased (P < 0.05) the glycosylated VOCs' terpene content. In Aleatico grapes, weight loss was key in modulating free volatiles, with 30% weight loss and 15 °C leading to significant increases in VOCs, especially exocarp terpenes, acids and benzenoids. More stressful dehydration (30% weight loss at 25 °C) resulted in higher aroma precursor concentrations. These findings can assist passito wine production in preserving varietal aromas of original grapes trough optimized dehydration conditions, preventing sensory homologation occurring because of strong uncontrolled dehydration. They can also promote optimization of energy consumption, thus fostering financial and environmental sustainability. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Impact of using yeast derivatives on the development of atypical aging in wines

Yeast derivatives (YDs) are commercial products obtained from yeast colonies grown in bioreactors then inactivated and dried. They are employed in winemaking to supply nitrogen (N), enhance yeast growth and remove unwanted compounds. Since glucose is the primary carbon and energy source for yeast growth, agricultural byproducts are commonly used in their production. Atypical aging (ATA) is a wine aroma defect arising from the oxidation of indole-3-acetic acid (IAA) to 2-aminoacetophenone (AAP). It entails the appearance of unpleasant odours as well as the rapid loss of varietal aromas. As IAA is one of the main plant hormones and YDs are often manufactured using material of plant origin, it can be assumed that AAP precursors are contained in those commercial formulations. If this is the case, the use of YDs could potentially increase the risk of obtaining ATA-tainted wines. To explore this hypothesis, 28 YDs were screened for the presence of AAP-related compounds, as well as their amino acidic content. Since several ATA precursors were detected, fermentation experiments were carried out in which different amounts of YD were added to different grape musts. Interestingly, depending on the nature of the commercial formulation, AAP development was observed to be either enhanced or diminished. More specifically, as well as concentration of AAP and precursors, the presence of cell walls within the YDs seemed to have an influence on the development of this defect. Furthermore, as diammonium phosphate (DAP) is also used to provide grape must with N, the effect of supplementing must with DAP was investigated. The addition of increasing doses of DAP did not significantly affect the accumulation of AAP. These results are very promising for both winemakers and YD producers, and they highlight the need for further research on the use of YDs in oenology.

Effects of winemaking techniques on the volatile compounds of Chelva wines

This study aimed to investigate the impact of three winemaking techniques on the volatile compounds and sensory profile of La Mancha Chelva wines, including wine elaborated by traditional white winemaking process (CW), wine enzymatically treated (WE), wine from must with skin contact treatment (SCW) and wine aging on lees (WL). A total of 32 varietal aroma compounds and 44 volatile compounds formed principally during alcoholic fermentation were identified and quantified by GC-MS independently of the winemaking technique and vintage year. WE showed the highest contents of terpenes, C13-norisoprenoids and benzenic compounds, SCW displayed major concentrations of C6 compounds whereas WL exhibited the major concentrations of the principal groups of volatile compounds formed mainly during alcoholic fermentation. All wines showed the same sequence of aromatic series, with the highest aroma contribution being those of the fruity, sweet and fatty series. The differences found in volatile compounds modified the sensory aroma profile of CW enhanced the main attributes. These results reveal that the winemaking process used had an important effect on the volatile composition of Chelva wines and can be used for optimizing the elaboration method to ensure wines in concordance with consumer preferences and that preserved the distinctive aromatic typicity of Cheva wines.

The Influence of Prefermentation Skin Contact, Stabulation, and Skin Fermentation on the Aromatic Behaviour and Phenolic Compounds of Important Austrian White Wine Cultivars

Many varietal aromas of wine are located in the berry skin. In the present study, we evaluated four important Austrian grape varieties: Grüner Veltliner, Sauvignon Blanc, Traminer, and Pinot Blanc. We assessed whether prefermentation skin contact, fermentation with the skin (only for Grüner Veltliner), and stabulation (lees stirring; only for Sauvignon Blanc, Traminer, and Pinot Blanc) could enhance the varietal aromas of the different grape cultivars. The aim was to intensify the varietal aromas without extracting the undesirable phenols. We performed a detailed analytical characterisation of approximately 100 volatile and phenolic compounds as well as a sensory characterisation. Although mash fermentation significantly increased the spicy aromas of Grüner Veltliner, which are affected by climate change (especially the sesquiterpene rotundone), it markedly decreased the fruitiness and increased the bitterness; therefore, it cannot be recommended for this cultivar. For Sauvignon Blanc, stabulation is a possible option; the varietal aromas (thiols and methoxypyrazines) were increased in the final wines of these variants. For Pinot Blanc and Traminer, prefermentation skin contact yielded the best results: for Traminer, it produced the highest content of monoterpenes (especially z-rose oxide), and for Pinot Blanc, it produced the highest content of ethyl esters. To summarise, stabulation will not completely replace classic skin contact, and mash fermentation is certainly not an alternative for the production of standard Grüner Veltliner wine. However, additional investigations are necessary with regard to other grape varieties, terroirs, and vintages before we can make final recommendations.

Pre-Fermentative Cryogenic Treatments: The Effect on Aroma Compounds and Sensory Properties of Sauvignon Blanc and Chenin Blanc Wine—A Review

Low-temperature treatments preceding alcoholic fermentation are becoming increasingly popular and have been used in winemaking as a tool to improve wine colour, aroma, and quality. Additionally, the pre-fermentative treatment of grapes with cryogenic agents protects the grape juice (must) from oxidation by reducing the diffusion of atmospheric oxygen into the liquid phase during the winemaking process. Resultant wines were reported to have enhanced varietal aromas, increased complexity, and higher thiol levels. Indications are that increased contact time between skin and juice improves the extraction of the compounds and/or precursors. Recently, there has been considerable interest in the production of wines with enhanced varietal aromas and improved quality by applying innovative winemaking technologies. This review aims to provide an overview of the aroma and organoleptic quality of Sauvignon blanc and Chenin blanc wines produced from grapes that were subjected to pre-fermentative cryogenic treatments including the impact aroma compounds, i.e., volatile thiols and methoxypyrazines.

Non-Saccharomyces Yeasts from Organic Vineyards as Spontaneous Fermentation Agents.

Currently, non-Saccharomyces yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation of non-Saccharomyces yeasts was addressed by their isolation during spontaneous fermentations of organic Verdejo grapes, obtaining a total of 484 isolates, of which 11% were identified by molecular techniques as non-Saccharomyces yeasts. Fermentative isolates belonging to the species Hanseniaspora meyeri, Hanseniaspora osmophila, Pichia guilliermondii, Pichia kudriavzevii, Torulaspora delbrueckii, and Wickerhamomyces anomalus were analysed. Significant differences were found in the yeast populations established at the different fermentation stages. Interestingly, W. anomalus stood up as a widely distributed species in vineyards, vintages, and fermentation stages. Several of the strains studied stood out for their biotechnological potential in the production of Verdejo wine, showing the presence of relevant enzymatic activity for the release of varietal aromas and the technological improvement of the winemaking process. Three enzymatic activities were found in an important number of isolates, β-glucosidase, protease, and β-lyase, implicated in the positive aromatic impact on this style of white wine. In that sense, all the isolates of W. anomalus presented those activities. T. delbrueckii isolates were highlighted for their significant β-lyase activity. In addition, T. delbrueckii was outlined because of its potential to achieve an elevated fermenting power, as well as the lack of lag phase. The results obtained highlight the importance of maintaining the microbial diversity that contributes to the production of wines with unique and distinctive characteristics of the production region.

Development of a New Method for the Quantitative Analysis of Aroma Compounds Potentially Related to the Fruity Aroma of Red Wines.

To determine the concentrations of aroma compounds involved in the fruity aroma of red wines, an analytical method was developed and optimized using liquid-liquid extraction and gas chromatography coupled to mass spectrometry (GC/MS). The aim was to reduce sample preparation and analysis time, with a single sample preparation and a single injection being needed to quantify 43 compounds. 19 esters, 13 monoterpenes, 5 C13-norisoprenoids, and 6 C6-aldehyde and alcohol compounds were quantified in 14 red wines made from different grape varieties grown in the Mediterranean basin. Samples were selected based on typical varietal aroma by a panel of experts, who produced 7 olfactory descriptors linked to desirable or non-desirable wine aromas. The instrumental analysis showed variations in concentrations of the quantified compounds among the wines. The wines described using positive fruity descriptors had higher mean total concentrations of esters, C6-alcohols, monoterpenes, and C13-norisoprenoids. Some non-ester compounds were positively correlated with the fruity descriptors. Sensory profile results obtained by a panel of 16 trained judges revealed that the addition of non-ester compounds (including 2 cyclic esters) to a red wine initially described as having cooked fruit aromas had a positive contribution to some fresh fruity notes. This study opens up new avenues for research on the potential involvement of non-ester compounds in the fruity expression of red wines.

ВЛИЯНИЕ БУТЫЛОЧНОЙ ВЫДЕРЖКИ НА СОСТАВ ОРГАНИЧЕСКИХ КИСЛОТ ВИН ИЗ СОРТОВ ВИНОГРАДА ВЕНГЕРСКОЙ СЕЛЕКЦИИ В УСЛОВИЯХ НИЖНЕГО ПРИДОНЬЯ

The aim of the work was to study the influence of bottle aging on the composition of organic acids and organoleptic properties of wines made from white grapevine varieties of Hungarian breeding growing in the Lower Don Region. The objects of the study were dry white wines made from grapevine varieties of Hungarian breeding − Bianca, Lakhedyi mesesh, Crystal, control − Aligote (Vitis vinifera L.), aged in a bottle from 1 to 3 years in the oenoteca of the Institute. The studies showed that during 3 years of aging the total content of organic acids (sum) decreased by 0.35−2.41 g/dm3. The largest decrease in the amount of organic acids was noted in the experimental wines from the variety Bianca (by 2.41 g/dm3). In the experimental wines the total amount of tartaric and malic acids was 56,8−76,3% of all the acids in the wine and decreased in the wines from variety Aligote (control) − by 11.2 %; Bianca − by 18.6 %; Lakhedi Mezesh − by 10,2 %; Kristall − by 7 % as it was aged in the bottle. The greatest decrease in tartaric acid concentration was observed in experimental wines of Bianca variety (by 2.4 g/dm3). In all the experiments the concentrations of succinic acid (by 13.3−28.3 %) and citric acid (by 20−38 %) decreased. The change of succinic acid content in the wines from Aligote variety (control) occurred after 2 years of aging in bottle, and of citric acid after 3 years of aging. In wines from varieties of Hungarian breeding (Bianca, Lakhedy Mesz, Crystal) it was observed that the change of citric acid content occurred after 2 years of aging and of amber acid content after 3 years. As a result of the organoleptic analysis it was determined that the highest tasting scores were given to Aligote (Control) (8,7−8,9 points) and Lakheddi mezesz (8,6−8,7 points), these wines during 3 years long aging had a bright varietal aroma, and more over their bouquet has improved, they have a light harmonious taste with a long pleasant aftertaste.

INFLUENCE OF MODERN STABILIZATION METHODS ON QUALITY VARIETAL WHITE WINES FROM UKRAINIAN BREEDING GRAPE

Modern winemaking in Ukraine is being significantly transformed and is actively developing. Our state has now turned to the search for its own wines and grape varieties. For international recognition, it is important to develop your case of wines that will be able to show the diversity of wine regions from Southern Bessarabia and the Northern Black Sea Coast to Transcarpathia. There are more and more small winemakers who are experimenting with new varieties, such as Sukholimansky white, Citronny Magaracha, Zagrei, Johanniter, Zvalgate, Solaris, Aromatny, Telti Kuruk and various muscat varieties. The organoleptic profile of such wines should express the varietal characteristics of local grape varieties and the agro-climatic features of the terroir. At the same time, the modern technology of white table wines should be built on the principles of maximum preservation of varietal aroma and minimization of its oxidation during the technological process. The article reflects the results of theoretical studies of literary sources regarding the mechanisms of oxidative processes of various nature in the process of grape processing; the market of modern preparations for stabilizing wine materials is considered. According to the goal, the influence of the use of the enzyme preparation Viazim clarif one on the process of clarifying the wort was investigated. The effect of complex antioxidant pasting of wort with the stepwise application of "Tanal W4", "Polygreen" and "Granula" bentonite on aromatic compounds and the formation of the aromatic profile of the finished product was also studied. At the last stage of research, the organoleptic profile of white wine materials of the studied grape varieties was determined. It was established that the general trend of stabilization processes in modern winemaking is transferred to the wort stage. According to the results of practical tests, in the form of trial pastes of wort, it is proposed to use the enzyme preparation "Viazim clarif one" at the stage of extracting wort; the effect of complex antioxidant pasting of wort with stepwise application of "Tanal W4", "Polygreen" and "Granula" bentonite was studied. Practical recommendations have been developed for winemakers on the application of antioxidant wort pasting for domestic grape varieties Sukholimansky white and Citronny Magaracha, which are now gaining popularity in Ukraine.

Identification of SNP loci and candidate genes genetically controlling norisoprenoids in grape berry based on genome-wide association study.

Obtaining new grapevine varieties with unique aromas has been a long-standing goal of breeders. Norisoprenoids are of particular interest to wine producers and researchers, as these compounds are responsible for the important varietal aromas in wine, characterized by a complex floral and fruity smell, and are likely present in all grape varieties. However, the single-nucleotide polymorphism (SNP) loci and candidate genes genetically controlling the norisoprenoid content in grape berry remain unknown. To this end, in this study, we investigated 13 norisoprenoid traits across two years in an F1 population consisting of 149 individuals from a hybrid of Vitis vinifera L. cv. Muscat Alexandria and V. vinifera L. cv. Christmas Rose. Based on 568,953 SNP markers, genome-wide association analysis revealed that 27 candidate SNP loci belonging to 18 genes were significantly associated with the concentrations of norisoprenoid components in grape berry. Among them, 13 SNPs were confirmed in a grapevine germplasm population comprising 97 varieties, including two non-synonymous mutations SNPs within the VvDXS1 and VvGGPPS genes, respectively in the isoprenoid metabolic pathway. Genotype analysis showed that the grapevine individuals with the heterozygous genotype C/T at chr5:2987350 of VvGGPPS accumulated higher average levels of 6-methyl-5-hepten-2-one and β-cyclocitral than those with the homozygous genotype C/C. Furthermore, VvGGPPS was highly expressed in individuals with high norisoprenoids concentrations. Transient overexpression of VvGGPPS in the leaves of Vitis quinquangularis and tobacco resulted in an increase in norisoprenoid concentrations. These findings indicate the importance of VvGGPPS in the genetic control of norisoprenoids in grape berries, serving as a potential molecular breeding target for aroma.

Study of the influence of fermentation conditions on the content of aroma-forming substances in young red wines

One of the main requirements for young wines is preservation the qualities of the grapes, including the bright varietal aroma characteristic of essential oils concentrated in the grape skins. At the same time, in the formation of the aroma of wine, substances synthesized by the enzyme systems of yeast cells are involved in the process of alcoholic fermentation. The main factors influencing the formation and ratio of aroma-forming substances in wine are the composition of the substrate, the race of yeast and the conditions for the fermentation process. Therefore, studies of the influence of the conditions of the fermentation process in the production of young red wine materials on the chemical composition of the aroma-forming components of wine are relevant. The analysis of the data obtained indicates the influence of the methods of carrying out the alcohol process on the content of aroma-forming compounds: aldehydes, ketones, higher and polyhydric alcohols, esters and fatty acids. It has been shown that the fermentation of the pulp wort, unlike carbon dioxide maceration, leads to a greater accumulation of oxidation products: acetaldehyde, acetoin and diacetyl, and also contributes to a higher content of higher alcohols. Under conditions of carbon dioxide maceration, a significant accumulation of aromatic alcohol – phenylethanol occurs. The conducted studies have shown that the use of carbon dioxide maceration using the Moldova grape variety generally has led to a significantly lower formation of oxidation products of both wort components and fermentation products. The additional introduction of carbon dioxide contributed to a decrease in the RH potential of the fermenting wort, which stimulated the accumulation of substances in a reduced form. At the same time, the content of esters in the case of artificial maceration is higher than under normal conditions, which indicates more intense enzymatic esterification reactions.It has been established that carbon dioxide maceration, in comparison with the classical processing of grapes, contributes to a greater formation and extraction of favorable aromatic components, and the additional introduction of carbon dioxide enhances this process.

Monitorization of Varietal Aroma Composition Dynamics during Ripening in Intact Vitis vinifera L. Tempranillo Blanco Berries by Hyperspectral Imaging.

The measurement of aromatic maturity during grape ripening provides very important information for determining the harvest date, particularly in white cultivars. However, there are currently no tools that allow this measurement to be carried out in a noninvasive and rapid way. For this reason, in the present work, we have studied the use of hyperspectral imaging (HSI)) to estimate the aromatic composition of Vitis vinifera L. Tempranillo Blanco berries during ripening. A total of 236 spectra in the VIS+short wave near-infrared (VIS+SW-NIR) range (400-1000 nm) of intact berries were acquired contactless under laboratory conditions. As gold standard values, a total of 20 volatile compounds were quantified by gas chromatography-mass spectrometry (GC-MS), and the concentration of total soluble solids (TSS) was measured by refractometry. Calibration, cross-validation, and prediction models were built using partial least squares (PLS). Values of RCV2 ≥ 0.70 were obtained for α-terpineol, p-cymene, β-damascenone, β-ionone, benzaldehyde, benzyl alcohol, hexanal, citral, linalool, 2-phenylethanol, octanoic acid, nonanoic acid, 2-hexenal, 2-hexen-1-ol, (Z)-3-hexen-1-ol, total C13 norisoprenoids, total C6 compounds, total positive compounds (i.e., the sum of all families except C6 compounds), total benzenoids, and total soluble solids (TSS). Therefore, it can be affirmed that HSI in the VIS + SW-NIR range could be a good tool to estimate the aromatic composition of Tempranillo Blanco grape berries in a contactless, fast, and nondestructive way.

STUDIES ON THE INFLUENCE OF THE PELICULAR MACERATION PROCESS ON THE QUALITY AND TYPICALITY OF SEMI-AROMATIC AND AROMATIC WINES

Traditionally, when making white wines, the musts are subjected to clarification and settling, even those from harvests in perfect phytosanitary condition. The increasingly perfected technical and technological procedures, involved in the operation of clarifying and deburring the musts, lead to the total removal of undesirable impurities, but also of the small fragments of skins and core, the only carriers of varietal aromas specific to each variety. In such situations, wines lacking fruitiness, aromatic "expressiveness" and varietal typicality result. In order to avoid such inconveniences, recently investigations have been intensified on the topic of improving white winemaking technologies, showing that the pellicular maceration is particularly appropriate, especially when the grapes are, at the time of harvesting, in a perfect state phytosanitary and are well matured. By applying pellicular maceration, notable results are obtained in the vinification of semi-aromatic (Sauvignon) and aromatic (Muscat Ottonel) grapes, but significant improvements were also obtained when using grapes of "neutral" aromatic varieties, such as those belonging to the Chardonnay variety.

Optical and AFM microscopy of grape juices treated with UHPH: Effects of microstructure and nanostructure

UHPH treatment of Vitis vinifera must for winemaking leads to fragmentation of colloidal particles into smaller structures. The shear and fracture forces experienced by grape juice during valve pressurization are sufficient to reduce the particle size of grape juice to below 500 nm. As a result, the applied force can disrupt bacterial and yeast cell structures, altering or breaking down proteins, polysaccharides and enzymes. This effect is not observed for low molecular weight compounds such as monomeric pigments and phenolic structures, varietal aroma precursors, fermentable sugars, etc. Treated and untreated samples can be compared using optical and atomic force microscopy. Optical microscopy images show reduction or elimination of bacteria and yeast and changes in microstructure. On the other hand, in addition to describing topography in the nanometer range, AFM can also measure particles in comparison to other techniques such as laser diffraction (LD). This work contributes to the characterization and better understanding of the effects of UHPH on grape juice for winemaking.

Varietal Aromas of Sauvignon Blanc: Impact of Oxidation and Antioxidants Used in Winemaking

Key varietal characteristics of Sauvignon Blanc, including the descriptors of ‘green’ and ‘tropical fruit’, are mostly attributed to methoxypyrazines and volatile thiols, while monoterpenes, higher alcohols, esters, fatty acids, and other volatile compounds also add complexity and fruity notes to the wines. During the winemaking and ageing period, oxidation decreases the concentrations of these compounds and diminishes the flavours derived from this aromatic grape variety. Therefore, antioxidants, such as sulfur dioxide, are commonly utilized in Sauvignon Blanc wine production for better preservation of those beneficial primary aromas. This review focuses on key varietal aromas in Sauvignon Blanc wine and how they are influenced by oxidation, and SO2 alternatives, including ascorbic acid, glutathione, and glutathione-enriched inactivated dry yeasts, that can be used in winemaking as antioxidants.

Atypical ageing defect in Pinot Blanc wines: a comparison between organic and conventional production management systems.

Atypical ageing (ATA) is an aroma defect that occurs in white wines and entails a loss of varietal aromas as well as scents of wet mop, shoe polish and dish rag. 2-Aminoacetophenone (2AAP) - a degradation product of indole-3-acetic acid (IAA) - has been described as the main odour-active compound and chemical marker responsible for this off-flavour. A stress reaction in the vineyard triggered by climatic, pedological and viticultural factors can ultimately cause ATA development in wines and remarkably affect wine quality. The aim of this research was to investigate the influence of three grapevine management systems on the occurrence of ATA. The experiments were carried out on Pinot Blanc grape samples from vines cultivated using one conventional and two organic approaches. The management systems mainly differed for the fertilisation regime and the weed control. The amino acid profiles as well as 2AAP and its precursors were quantified in musts and wines using ultra-high-performance liquid chromatography coupled to a high-resolution mass spectrometer. The results showed the existence of a strong vintage effect, while no influence of the use of different agronomic systems was observed. The study revealed that an efficient implementation of different grapevine production systems did not affect ATA development in Pinot Blanc wines. This finding is of great relevance for winegrowers and winemakers as it demonstrates that a well-planned organic management system correctly adjusted to the climatic conditions does not pose a threat towards the development of ATA-related compounds in wine. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Flint glass bottles cause white wine aroma identity degradation

Due to marketing recommendations, white wines are often bottled in flint glass to improve aesthetics and showcase wine color. Although this practice is known to cause a wine fault, the influence of light on the fruity and flowery aromatic profile of wine is unknown. The aim of this study was to investigate the changes to the white wine volatilome under typical supermarket shelf conditions, using 1,052 bottles of 24 white wines. After only 7 d of shelf life in flint glass bottles, a dramatic loss in terpenes (10 to 30%) and norisoprenoids (30 to 70%) was recorded, whereas colored glass bottles did not evidence such behavior even after 50 d, and darkness preserved the wine's fruity and flowery aromatic integrity. We also proposed an alternative mechanism for the insurgence of the lightstrike off-odor, which takes the varietal aroma loss into account. In light of this understanding of the flint glass negative impact on white wine aroma identity and sensorial character, this packaging should be strongly discouraged. The same findings should be valid for a wide range of several daily consumed foodstuff where transparent packaging is used.