Search

The objective of this study was to analyze the minerals transferred to Sauvignon blanc must and wine as an effect of foliar fertilizer application. The mineral composition was determined via atomic absorption spectroscopy. Experimental leaf and berry samples were examined during the phenological grapevine growth phases. A foliar fertilizer mixture (0.5 L/hL) with humic acids (8.51%) and B (0.031 kg) was applied. It was observed that the application of humic acids and boron significantly influenced the quality of Sauvignon blanc wine samples. During the blooming period, there was a statistically significant increase (p < 0.05) in P, K, and B in the experimental group. The results showed that using HAs and B in foliar fertilizer significantly (p < 0.05) increased the concentration of minerals in the experimental group. However, P and Fe content in the leaves decreased after veraison. After processing the berries in the vinification process, the levels of B in the must (0.71 ± 0.06 mg/kg) and, subsequently, in the wine (0.61 ± 0.06 mg/kg) were significantly (p < 0.05) higher in the experimental group. Data showed that the foliar fertilizer significantly increased the concentration of N (176.24 ± 0.02 mg/L) in the experimental must. These changes were also observed in wine samples. In wine, a statistically significant decrease in Ca (82.86 ± 0.29 mg/kg) was observed. [ABSTRACT FROM AUTHOR]

The study of the disease Black rot of grapes was carried out in the village of Galabets, Pomorie municipality. The study was carried out in the period of 2022 - 2023. The vine varieties that were monitored were Dimyat, Pamid, Misquet red, Chardonnay, Misquet Ottonel, Naslada, June Blanc and Cabernet Sauvignon. In the village of Galabets, the Misquet Ottonel variety is 2.5/1.4 m apart and the other varieties at distances of 3.2/1.4 m. The vines are grafted onto Berlandieri x Riparia SO4 rootstock. The preplanting preparation of the area includes stock fertilization with 40 kg of P2O5, 50 kg of K2O (active substance) and 3 t of stable manure per decare, harrowing, discing and leveling. The vines are planted in pits of 60/60/70 cm. According to McKinney's classification (1923), slightly sensitive /class 1/ are June Blanc and Naslada (0.1-25%), moderately sensitive is the variety Pamid (25-50%). Misquet Otonel, Misquet Red, in fourth variant compared to the other variants and the lowest, are sensitive. This is due to the application of green pruning operations combined with the use of chemical preparations with a proven effect against black rot. [ABSTRACT FROM AUTHOR]

Leaf chlorophyll content is a key indicator of plant physiological status in viticulture; therefore, regular evaluation to obtain data for nutrient supply and canopy management is of vital importance. The measurement of pigmentation is most frequently carried out with hand-held instruments, destructive off-site spectrophotometry, or remote sensing. Moreover, smartphone-based applications also ensure a promising way to collect colorimetric information that could correlate with pigmentation. In this study, four grapevine genotypes were investigated using smartphone-based RGB (Red, Green, Blue) and CIE-L*a*b* colorimetry and a portable chlorophyll meter. The objective of this study was to evaluate the correlation between leaf chlorophyll concentration and RGB- or CIE-L*a*b*-based color indices. A further aim was to find an appropriate model for discriminating between the genotypes by leaf coloration. For these purposes, fully developed leaves of 'Chardonnay', 'Sauvignon blanc', and 'Pinot noir' clones 666 and 777 were investigated with the Color Grab smartphone application to obtain RGB and CIE-L*a*b* values. Using these color values, chroma, hue, and a further 31 color indices were calculated. Chlorophyll concentrations were determined using an Apogee MC100 device, and the values were correlated with color values and color indices. The results showed that the chlorophyll concentration and color indices significantly differed between the genotypes. According to the results, certain color indices show a different direction in their relationship with leaf pigmentation for different grapevine genotypes. The same index showed a positive correlation for the leaf chlorophyll concentration for one variety and a negative correlation for another, which raises the possibility that the relationship is genotype-specific and not uniform within species. In light of this result, further study of the species specificity of the commonly used vegetation indices is warranted. Support Vector Machine (SVM) analysis of the samples based on color properties showed a 71.63% classification accuracy, proving that coloration is an important ampelographic feature for the identification and assessment of true-to-typeness. [ABSTRACT FROM AUTHOR]

Shoot topping is a management method in the search for a vegetative and productive balance in the grapevine. However, there is little information about its effect on the architecture of the bunches and on the occurrence of Botrytis bunch rot. In this context, the aim of this study was to evaluate the effect of different shoot topping times on cluster architecture and the temporal dynamics of Botrytis bunch rot in 'Sauvignon Blanc' grapevines. The work was carried out in the 2016/2017 harvest, in a commercial vineyard located in the municipality of São Joaquim. The treatments consisted of the management of the shoot topping, removing approximately 50 cm from the apical portion of the branches at different phenological stages: plants without shoot (control), separate inflorescence, full bloom, pea-sized berries and veráison. Bunch architecture and the temporal dynamics of Botrytis bunch rot were evaluated. The shoot topping the 'Sauvignon Blanc' grapevine did not influence the architecture of the bunches, regardless of the phenological stage at which it was carried out. About Botrytis bunch rot, there was no effect for the different shoot topping times on the onset of symptoms, time to reach maximum incidence and time to reach maximum severity, as well as for the disease incidence and severity variables, although there was an effect on the AUDIPC and AUDSPC areas, with the highest values being observed in the full bloom phenological stage for AUDIPC and in the veraison for AUDSPC. Therefore, it is recommended to carry it out on the pea berry. [ABSTRACT FROM AUTHOR]

The Campanha Gaúcha region has recently (2020) received an Indication of Provenance ('IP Campanha Gaúcha') for wines and sparkling wines. Scientific data and research developed during the last decades could provide the necessary information for this first characterization of the area. Nevertheless, there is a lack of detailed data about the composition of Campanha Gaúcha wines. In this study, five Campanha Gaúcha white wines of different grape varieties (Riesling, Gewürztraminer, Semillon, Sauvignon Blanc and Chardonnay) produced in the 2018 vintage were collected directly from the winery and followed analyses of several volatile and phenolic compounds. The 2018 vintage was rated among the best of the 3 preceding decades for this region. The results, originated from this excellent vintage, demonstrate the qualitative potential of the region for the wines elaborated with the grape varieties covered by this study. They are important records for the construction and enlargement of databases for future research and can also provide further scientific basis for more detailed definition of intra-regional and inter-regional differences and similarities regarding the characteristics of Campanha Gaúcha wines. [ABSTRACT FROM AUTHOR]

At present, non-alcoholic beers and low-alcoholic beers (NABLABs) suffer from premature oxidation when fresh, and from a lack of fruity fermentation aromas. In wines, dimethylsulfide (DMS) is known to enhance truffle nuances and the fruity character. This offers an opportunity to improve the flavor of NABLABs. In this work, levels of free DMS and its potential precursors (S-methylmethionine/SMM and dimethylsulfoxide/DMSO) were assessed in eleven commercial NABLABs, in parallel with their amounts of fruity esters and polyfunctional thiols. Except in two dry-hopped samples and a fruity beer, free DMS was detected at very low levels in all fresh NABLABs (four samples even displayed no detectable GC peak), likely because of dealcoholization or too-short fermentation. Through NABLABs aging, the free DMS concentration increased (+63% on average after two years), at a degree correlated with the initial SMM level (2–118 µg/L DMS eq.; R2 = 0.79). This SMM amount revealed to be also correlated with the group I amino acid residual content (more consumed through traditional fermentations). Unlike DMSO, SMM showed significant release of free DMS after aging in spiking experiments (4% degradation after 30 days at 20 °C). As fruity fermentation esters are found in NABLABs at much lower concentrations than in conventional lagers, increasing both DMS and polyfunctional thiols by dry hopping (or DMS-enriched extracts) emerges as an opportunity to improve them. [ABSTRACT FROM AUTHOR]

The wine market is affected by the origin of wines, but the current wine traceability system has some limitations. The idea of geographical authenticity and quality has increased as one of the most important parameters influencing consumers' preferences. Chemical parameters such as total polyphenolic content (TPC), alcohol and organic acid content (total acids, malic and tartaric acids), and antioxidant activity were observed in this work at 15 dry white wines of varieties Pinot blanc, Riesling, Sauvignon blanc, and Chardonnay, which originated from three different countries. FTIR and spectrophotometry methods (TPC and DPPH) were used and chemometric approaches such as ANOVA and PCA were selected as the most important for evaluation. In general, high levels of malic acid, TPC, and antioxidant activity were detected in Austrian wines. Pinot blanc, Chardonnay, and Sauvignon from the same producing region in Austria showed higher results. The higher overall acid concentration was a distinguishing feature of the Slovakian Sauvignon and Riesling varieties, particularly in the case of tartaric acid. Austrian samples showed significantly higher antioxidant activity compared to Hungarian Chardonnay (p = 0.002) and Sauvignon (p = 0.007), comparable to TPC. The application of statistical analysis was useful in demonstrating many discrepancies, particularly by application of the PCA method. [ABSTRACT FROM AUTHOR]

The aging ability of dry white wines has been increasingly recognized. The present work aimed to identify which sensory features drive their quality assessment by experienced tasters. Individuals assessed several sensory attributes, using dark tasting glasses. Wines originated from the grape varieties Alvarinho, Arinto, Sauvignon Blanc and Pinot Bianco with a wide range of ages. Basic physical–chemical analysis, browning (Abs 420 nm), elemental composition and a partial volatile fraction were also determined. The overall quality scores were a function of complexity and balance and were negatively influenced by the perception of faultiness. The aging process could be associated with a continuous sensory space characterized by a declining perception of freshness and an intensification in the mellowed flavors. Despite their age, wines were characterized by an austere perception caused by their acidity, saltiness, bitterness, smoothness and dryness. Nevertheless, quality scores were similar from the youngest to the oldest tasted wines (17 years old). The exception was a Sauvignon Blanc wine from a recent vintage that was judged as faulty due to the perception of earthiness. Overall, the tasted wines displayed an unexpected aging ability as demonstrated by the difference between the predicted and real wine ages. To improve the recognition of old wines, the metaphor "mellowed by age" is proposed to describe flavors resulting from beneficial aging instead of "oxidized by age". [ABSTRACT FROM AUTHOR]

BACKGROUND: Higher alcohol acetates (HAAs) are potent aroma‐active esters that impart desirable fruity and floral aromas. However, the conversion of higher alcohol precursors into HAAs is extremely low in winemaking. To investigate the underlying yeast–yeast interaction on targeted improvement of aromatic HAAs, we evaluated fermentation activity, cell viability, amino acid consumption and HAA production when Pichia kluyveri and Saccharomyces cerevisiae were inoculated concurrently or sequentially. RESULTS: Pichia kluyveri PK‐21 possessed the ability to survive and increased HAA level up to 5.2‐fold in mixed fermentation. Such an increment may benefit from the efficient conversion of higher alcohol precursors into HAAs (>27‐fold higher than S. cerevisiae). During mixed fermentation, the two yeasts exhibited crucial interactions regarding cell growth and amino acid competition. Saccharomyces cerevisiae dominated over the co‐inoculated P. kluyveri by efficient uptake of amino acids and biomass production. However, this dominance decreased in sequential fermentation, where P. kluyveri growth increased due to the consumption of preferred amino acids prior to S. cerevisiae. Pearson correlation analysis indicated that phenylalanine and aspartic acid may act as positive amino acids in boosting P. kluyveri growth and HAA production. Laboratory‐scale winemaking validated the fermentation performance of P. kluyveri in sequential inoculum, resulting in a balanced aroma profile with enhanced floral and tropical fruity characteristics in the final wines. CONCLUSION: This study proposes a microbial, non‐genetically engineered approach for targeted increase of HAA production in winemaking and the findings provide new insights into yeast–yeast interactions. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Non-Saccharomyces yeasts have great potential in improving wine quality, showing personality characteristics, and highlighting the terroir of wine. In this study, we evaluated the impact of simultaneous inoculation with the non-Saccharomyces yeasts Torulaspora delbrueckii or (and) Hanseniaspora uvarum in combination with Saccharomyces cerevisiae (EC1118 or VL3) on the aromatic compounds and sensory quality of Sauvignon blanc wines. The growth of yeast groups in the alcoholic fermentation process was tracked using fluorescence in situ hybridization. The presence of non-Saccharomyces yeast notably impacted the distribution of S. cerevisiae and was related to the species of yeast. The co-fermentation of H. uvarum and S. cerevisiae improved the content of total esters, especially acetate esters. Simultaneous inoculation of T. delbrueckii or (and) H. uvarum significantly increased the content of total terpenes, especially linalool. Similar results were found for some higher alcohols and organic acids. Sensory evaluation showed that the wines mixed fermentation with H. uvarum had significantly tropical fruit aroma characteristics. Citrus and mineral notes, typical aroma characteristics of Sauvignon blanc wine, were enhanced by mixed fermentation strategies with T. delbrueckii or (and) H. uvarum and different S. cerevisiae. Hence, co-fermentation by T. delbrueckii or H. uvarum combined with S. cerevisiae could significantly improve the sensory quality of Sauvignon blanc wine. [ABSTRACT FROM AUTHOR]

Aims Arbuscular mycorrhizal fungi (AMF) can perform significant functions within sustainable agricultural ecosystems, including vineyards. Increased AMF diversity can be beneficial in promoting plant growth and increasing resilience to environmental changes. To effectively utilize AMF communities and their benefits in vineyard ecosystems, a better understanding of how management systems influence AMF community composition is needed. Moreover, it is unknown whether AMF communities in organically managed vineyards are distinct from those in conventionally managed vineyards. Methods and Results In this study, vineyards were surveyed across the Marlborough region, New Zealand to identify the AMF communities colonizing the roots of different rootstocks grafted with Sauvignon Blanc and Pinot Noir in both conventional and organic systems. The AMF communities were identified based on spores isolated from trap cultures established with the collected grapevine roots, and by next-generation sequencing technologies (Illumina MiSeq). The identified AMF species/genera belonged to Glomeraceae, Entrophosporaceae, and Diversisporaceae. The results revealed a significant difference in AMF community composition between rootstocks and in their interaction with management systems. Conclusions These outcomes indicated that vineyard management systems influence AMF recruitment by rootstocks and some rootstocks may therefore be more suited to organic systems due to the AMF communities they support. This could provide an increased benefit to organic systems by supporting higher biodiversity. [ABSTRACT FROM AUTHOR]

(1) Background: Spring frost damage is a common phenomenon that occurs in Southern Chile that considerably affects vine productivity and grape quality. (2) Methods: A field trial was conducted in order to study vine phenology and berry physicochemical parameters in Chardonnay, Sauvignon Blanc and Pinot Noir ungrafted and grafted (onto 101-14 Mgt rootstock) grapevines after a spring frost. This event killed the totality of primary bud shoots when the vines reached the phenological stage of unfolded leaves. (3) Results: From budburst, to flowering of secondary bud shoots, ungrafted Sauvignon Blanc grapevines presented an advanced phenology, whereas 101-14 Mgt rootstock tended to advance the maturity of Pinot Noir grapevines from flowering to ripening of berries. At harvest, berries from secondary buds of vines grafted onto 101-14 Mgt rootstock showed higher soluble solids than the ones from ungrafted Chardonnay and Sauvignon Blanc vines. High total phenolic content was found in berries from secondary buds of the grafted vines, compared to the ones from the ungrafted vines. Berry soluble solids variability tended to statistically decrease toward harvest in the studied plant materials, and the maximum coefficient of variation for soluble solids, berry weight, berry firmness and berry size reached 9.5%, 25.9%, 18.6% and 8.9%, respectively. (4) Conclusions: These preliminary results may be interesting for the Southern Chilean viticulturists since it seems that 101-14 Mgt rootstock could affect phenology and grape berry maturity of grapevines established in the Cautín Valley after spring frost damage. [ABSTRACT FROM AUTHOR]

At harvest, the metabolic composition of wine grapes reflects the accumulated effect of the environmental conditions, the stresses endured, and viticultural manipulations applied during the growing season. The role of the winemaker is to extract and nurture this “metabolite potential” throughout the winemaking process. However, it is typically difficult to relate this grape potential to that of the eventual wines. In this study, a holistic view of Sauvignon Blanc grape and wine polyphenolic compounds was attempted by measuring these compounds from different matrices, from ripe grape tissues up to the final wine, including the submatrices, such as juice, pomace and sediment. Sauvignon Blanc vines from one vineyard block were manipulated to yield berries with distinctly different phenolic potentials by creating a high light (HL) or a low light (LL) microclimate in the fruiting zone of the canopy during the growing season. The analyses of the HL and LL berries and wines, as well as concomitant analyses of the phenolic compounds in the submatrices, allowed their tracing as they were (i) transferred from one matrix to another, (ii) lost as waste products, or (iii) affected by different winemaking practices (skin contact and/or fermentation in contact with the juice sediment) implemented in the experimental design. In berries, flavonols showed the largest increase due to sun exposure (HL treatment) but were absent from the juice samples at all juice processing stages. They were however detected in the juice sediment, together with high concentrations of organic acids and sugars. Juice processing was noted for dramatic fluctuations in metabolite concentrations suggesting intense metabolic activity in this pre-fermentation matrix. Both skin contact and sediment contact treatments delivered wines with higher concentrations of coutaric acid (the ester formed from coumaric and tartaric acid) and the flavanol catechin while epicatechin concentrations was unaffected. The higher catechin concentrations did not lead to increased perceived bitterness in the wines, except in the sediment contact treatments. The total phenolic compound concentration of wine from LL (low phenolic potential) grapes was comparable to wine from HL (high phenolic potential) grapes, when skin contact, or sediment contact treatments were employed. From a sensory perspective, the sediment contact decreased the fruity aromas of Sauvignon Blanc, while the skin contact treatment enhanced the sensorial properties of the wines made from the LL grapes, allowing increased extraction from the skin-accumulated impact compounds.

Chardonnay and Sauvignon blanc wines aged in oak wood barrels with low and medium tannin potentials were discriminated for their abilities to resist against oxidation during bottle storage. The oak wood tannin potential was positively correlated to wines antioxidant capacity after 2 and 4 years of bottle aging. Untargeted molecular analysis revealed that the Sauvignon blanc metabolome was more affected by the tannin potential than the Chardonnay. Supervised statistical analysis highlighted the extensive oak wood contribution to the wine chemical fingerprints. Wines aged in barrel of medium tannin potential were associated with higher concentrations in antioxidant compounds such as dipeptides. Moreover, quantitative differences were observed between oak barrel derived volatile compounds. Sauvignon blanc volatile thiols appeared to decrease during bottle aging, regardless of the oak tannin potential. This study highlights the post bottling positive impact of oak wood barrel aging on wines oxidative stability, related to oak barrel tannin potential.

The grape variety and the different aging techniques used in the winemaking are key factors that can affect the chemical and sensory profile of wines and allow to differentiate from other wines. The aim was the chemical and sensory characterization of white wines elaborated with different grape varieties (Verdejo, Sauvignon Blanc and Godello) and with different winemaking techniques (aging on lees, oak barrel fermentation combined with aging on lees (FB + L), and without aging). The Godello wines had higher alcohol and polysaccharide content, terpene volatile groups and 2-phenyethanol which supply floral notes. The Verdejo wines had the highest content of total tannins, total polysaccharides, and ethyl esters, whiskey lactones and aldehydes, compounds that supply fruity, oak and some negative (bad smell) nuances respectively. The Sauvignon Blanc wines had the highest content of tartaric esters and flavonols, and volatile groups of alcohol acetates, C6 alcohols and aldehydes which supply fruity, herbaceous and some negative aromas, respectively. The FB + L technique contributed to the extraction of polysaccharides, phenols and volatile compounds from oak and lees, increasing the body, persistence and olfactory intensity due to the compounds provided by the oak wood. These wines had a similar content of terpenes than wines without aging, which can increase their sensory complexity. [ABSTRACT FROM AUTHOR]

The influence of the geographical location on the chemical composition of commercial Sauvignon Blanc wines was investigated. The assay was carried out on Sauvignon Blanc wines from three cold-climate valleys in Central Chile, Casablanca, Leyda, and San Antonio. The analyses revealed clear variations in some chemical parameters, especially in titratable acidity, which was higher in the geographical areas closest to the Pacific Ocean, such as the Leyda and San Antonio valleys. Regarding the composition of low-molecular-weight phenolic compounds, 17 compounds were found, and the results show that the Casablanca valley exhibits a greater abundance of monomeric flavanols, such as (+)-catechin, whereas the Leyda valley shows a higher abundance in flavonols and phenolic acids esterified with tartaric acid. Concerning the aromatic compound profile, the wines from the Casablanca valley showed a greater abundance of esters, C13 norisoprenoids, and some terpenes. The PLS-DA analysis revealed some differences, especially between wines from Casablanca and Leyda, demonstrating that the difference in the chemical composition of the wines was influenced by the geographical area. [ABSTRACT FROM AUTHOR]

Background and Aims. Bentonite fining is commonly used in white wine production, which can lead to the loss of wine volume and aroma compounds. Many factors influence the efficacy of bentonite fining. The effect of pH adjustment and timing of bentonite addition were studied for their combined effects on Sauvignon Blanc wine protein haze formation and bentonite requirement at microscale and commercial scale. Methods and Results. Three bentonite addition timings were conducted on a juice pH adjustment trial: before fermentation, during fermentation, and after fermentation. The hot and cold test was utilized to determine the bentonite requirement for protein stabilization. Wine proteins were analyzed using a modified Coomassie brilliant blue (CBB) assay, lithium dodecyl sulphate polyacrylamide gel electrophoresis (LDS‐PAGE), and sodium dodecyl sulphate capillary gel electrophoresis (SDS‐CGE). Lower juice pH (2.80 and 3.00) resulted in sluggish fermentation, whereas the presence or absence of bentonite during fermentation showed similar fermentation kinetics at each pH. The presence of bentonite remaining in contact with ferment improved the completion of fermentation for the most sluggish ferment (pH 2.80). Commercial wine made from same batch of juice was adjusted to different pH values, and low‐pH wines had a lower wine protein content and an increasing protein adsorption efficiency of bentonite fining, leading to lower bentonite requirement. Conclusions. Bentonite addition during fermentation was the most efficient in protein removal but fining after fermentation required the least overall bentonite dosage. The different fermentation scales (i.e., microscale versus commercial scale) slightly affected wine protein contents but not molecular weight (MW) profiles. Protein contents and MW profiles in stabilized wines were affected by the original juice pH with more complex patterns from high‐pH juice. Significance of the Study. The findings of this study provide valuable information on optimization of bentonite fining to minimize the dosage so as to reduce the loss of wine volume and quality. [ABSTRACT FROM AUTHOR]

β C-S lyases (β-CSLs; EC 4.4.1.8) are enzymes catalyzing the dissociation of β carbon–sulfur bonds of cysteine S-conjugates to produce odorant metabolites with a free thiol group. These enzymes are increasingly studied for their role in flavor generation in a variety of food products, whether these processes occur directly in plants, by microbial β-CSLs during fermentation, or in the mouth under the action of the oral microbiota. Microbial β-CSLs react with sulfur aroma precursors present in beverages, vegetables, fruits, or aromatic herbs like hop but also potentially with some precursors formed through Maillard reactions in cooked foods such as meat or coffee. β-CSLs from microorganisms like yeasts and lactic acid bacteria have been studied for their role in the release of polyfunctional thiols in wine and beer during fermentation. In addition, β-CSLs from microorganisms of the human oral cavity were shown to metabolize similar precursors and to produce aroma in the mouth with an impact on retro-olfaction. This review summarizes the current knowledge on β-CSLs involved in flavor generation with a focus on enzymes from microbial species present either in the fermentative processes or in the oral cavity. This paper highlights the importance of this enzyme family in the food continuum, from production to consumption, and offers new perspectives concerning the utilization of β-CSLs as a flavor enhancer. [ABSTRACT FROM AUTHOR]

In this study, the development trends of bioclimatic parameters recorded at the Maribor and Murska Sobota climate stations from 1952 to 2022 and the dynamics of grape ripening in early-, medium-, and late-ripening grape varieties in the Podravje wine-growing region in Slovenia (north-eastern Slovenia) from 1980 to 2022 were investigated. Based on the data on soluble solids content, total acidity, and the recommended harvest date per year (until the technological ripeness of the grapes; 76°Oe), trends for shortening the growing period of the vines were calculated. Temperature changes have been more pronounced since 1980. The number of so-called hot days (with a maximum of T > 30 °C) has increased the most, which has the greatest impact on other bioclimatic parameters, e.g., the average temperature and growing degree days (GDDs) and the Huglin index (HI). For the period of 1980 to 2022, the trends were 0.44 °C (Murska Sobota) and 0.51 °C (Maribor) per decade, respectively. The trends were more pronounced for the average temperature in the period of May–June (TMJ). After 1980, the HI increased by about 10 units per year. As a result of the climate warming, grapes in north-eastern Slovenia ripened 26 ('Sauvignon Blanc') to 35 ('Welschriesling') days earlier. The trends showed a decrease in total acidity, which can be attributed to the higher temperatures during the growing season period, especially during the ripening period of the grapes (véraison). After 2010, the average temperatures during the growing season (1 April to 31 October) in Podravje were 1.6 °C higher than in the 1980s. In line with the earlier ripening of the grapes, the actual average temperature from 1 April to the harvest date was a further 1.0 °C higher. The higher temperatures in the late-ripening varieties 'Riesling' and 'Furmint' had a positive effect on the lower total acidity. Total annual precipitation and precipitation in the growing season for the period 1980 to 2022 in the Maribor area show decreasing trends of 6 mm/m2 (p = 0.001) and 4 mm/m2 (p = 0.012), respectively. In the eastern sub-wine-growing region of Podravje (Murska Sobota), the trends in precipitation were not significant. [ABSTRACT FROM AUTHOR]

This study investigates innovative approaches to improve the quality and aroma characteristics of Muscat Hamburg wine production by substituting the conventional Saccharomyces cerevisiae yeast with an efficient fermentation strain of Schizosaccharomyces pombe. The typical use of S. cerevisiae in Muscat Hamburg wine often leads to uniformity and prolonged processing times, requiring subsequent malolactic fermentation to degrade excessive malic acid. The study advocates for the replacement of S. cerevisiae with a specific S. pombe strain, Sp-410, isolated from the fermented grains of sauce-flavor Baijiu, a Chinese spirit. Muscat Hamburg wine fermented with the S. pombe strain demonstrates decreased malic acid levels, offering a potential alternative to malolactic fermentation. However, exclusive S. pombe fermentation may result in an overproduction of acetic acid metabolites, leading to a monotonous taste. In response, the study proposes a mixed fermentation approach, combining the S. pombe strain with a Saccharomyces uvarum strain and a non-Saccharomyces yeast, Torulaspora delbrueckii. The optimized mixed fermentation strategies (M:SP+TD and M60SP+TD) involve specific proportions and intervals of inoculation, aiming to enhance the quality and aroma complexity of Muscat Hamburg wine. In conclusion, this research contributes to advancing the production of high-quality Muscat Hamburg wines, utilizing S. pombe as the primary yeast strain and implementing mixed fermentation methodologies. [ABSTRACT FROM AUTHOR]

Based on the current research on the wine grape variety recognition task, it has been found that traditional deep learning models relying only on a single feature (e.g., fruit or leaf) for classification can face great challenges, especially when there is a high degree of similarity between varieties. In order to effectively distinguish these similar varieties, this study proposes a multisource information fusion method, which is centered on the SynthDiscrim algorithm, aiming to achieve a more comprehensive and accurate wine grape variety recognition. First, this study optimizes and improves the YOLOV7 model and proposes a novel target detection and recognition model called WineYOLO-RAFusion, which significantly improves the fruit localization precision and recognition compared with YOLOV5, YOLOX, and YOLOV7, which are traditional deep learning models. Secondly, building upon the WineYOLO-RAFusion model, this study incorporated the method of multisource information fusion into the model, ultimately forming the MultiFuseYOLO model. Experiments demonstrated that MultiFuseYOLO significantly outperformed other commonly used models in terms of precision, recall, and F1 score, reaching 0.854, 0.815, and 0.833, respectively. Moreover, the method improved the precision of the hard to distinguish Chardonnay and Sauvignon Blanc varieties, which increased the precision from 0.512 to 0.813 for Chardonnay and from 0.533 to 0.775 for Sauvignon Blanc. In conclusion, the MultiFuseYOLO model offers a reliable and comprehensive solution to the task of wine grape variety identification, especially in terms of distinguishing visually similar varieties and realizing high-precision identifications. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "The Effect of Yeast Inoculation Methods on the Metabolite Composition of Sauvignon Blanc Wines." The correction addresses a technical error in the calculation of yeast cell concentrations in the original publication. The corrections have been made throughout the manuscript, including the abstract, methods, results and discussion, and conclusion sections. The correction also includes updates to figures and tables in the article. The given text consists of three tables that provide data on yeast fermentations and the resulting thiols in Sauvignon blanc wines. The first table shows the fermentation results for different yeast inoculations, while the second table presents the concentrations of three major varietal thiols in the wines. The third table displays the viability testing results for each fermentation and treatment. The authors state that the scientific conclusions remain unaffected, and the original publication has been updated. [Extracted from the article]

Cluster thinning has been widely applied in yield management and its effect on green leaf volatiles (GLVs) in wines has seldom been studied. GLVs are important flavor compositions for grapes and wines. This work aimed to investigate the impact of cluster thinning on these volatiles and their precursors in grapes and wines. Severe cluster thinning (CT1) and medium cluster thinning (CT2) were performed on Cabernet Sauvignon (Vitis vinifera L.) vines in two sites (G-farm and Y-farm) from Xinjiang province in the Northwest of China. The impact of cluster thinning treatments on the accumulation of GLVs and their precursors, long chain fatty acids (LCFAs) of grape berries and C6 volatiles, in resulting wines was investigated. Multivariate analysis showed that cluster thinning treatments induced significant changes in fruit and wine composition in both farms. In Y-farm, medium cluster thinning (CT2) significantly increased the average cluster weight of harvested berries. Additionally, both cluster thinning treatments (CT1 and CT2) increased fatty acids in harvested berries and CT2 led to an increase in C6 esters and a decrease in C6 alcohols in the wines of Y-farm under the warmer and drier 2012 vintage. However, the effect of cluster thinning was likely negative in G-farm due to its wetter soil and excessive organic matter. The treatments may be applicable for local grape growers to improve viticultural practices for the more balanced vegetative and reproductive growth of Cabernet Sauvignon grapevines. This work also provided further knowledge on the regulation of fatty acids and the derived C6 volatiles through the lipoxygenase (LOX) pathway. [ABSTRACT FROM AUTHOR]

This document is an editorial from the journal Frontiers in Microbiology titled "Microbial modulation to mitigate the impact of climate change on wine production." The editorial emphasizes the importance of understanding and managing microorganisms in vineyards and during winemaking to preserve the quality of wine in the face of climate change. It discusses the potential benefits of using non-Saccharomyces yeasts and unconventional biotechnological strategies to improve wine production and safety. The editorial also highlights the role of yeast co-inoculations in modulating the aromatic profiles of wines. Overall, the document provides up-to-date research on microbial modulation in wine production and its potential to mitigate the effects of climate change. [Extracted from the article]

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. [ABSTRACT FROM AUTHOR]

SO2 plays an important role in wine fermentation, and its effects on wine aroma are complex and diverse. In order to investigate the effects of different SO2 additions on the fermentation process, quality, and flavor of 'Beibinghong' ice wine, we fermented 'Beibinghong' picked in 2019. We examined the fermentation rate, basic physicochemical properties, and volatile aroma compound concentrations of 'Beibinghong' ice wine under different SO2 additions and constructed a fingerprint of volatile compounds in ice wine. The results showed that 44 typical volatile compounds in 'Beibinghong' ice wine were identified and quantified. The OAV and VIP values were calculated using the threshold values of each volatile compound, and t the effect of SO2 on the volatile compounds of 'Beibinghong' ice wine might be related to five aroma compounds: ethyl butyrate, ethyl propionate, ethyl 3-methyl butyrate-M, ethyl 3-methyl butyrate-D, and 3-methyl butyraldehyde. Tasting of 'Beibinghong' ice wine at different SO2 additions revealed that the overall flavor of 'Beibinghong' ice wine was the highest at an SO2 addition level of 30 mg/L. An SO2 addition level of 30 mg/L was the optimal addition level. The results of this study are of great significance for understanding the effect of SO2 on the fermentation of 'Beibinghong' ice wine. [ABSTRACT FROM AUTHOR]

Green leaf volatiles (GLVs) are important in giving grape a fresh and green aroma. But the changes in GLVs during the phenological development of grapevines are not well known. This study analyzed the GLVs and transcription levels of associated biosynthetic genes in six grape species from the Loess Plateau region at five stages of maturation. Thirteen GLVs were detected, showing unique patterns for each grape type at various growth phases. The primary components in six grapes were (E)-2-hexenal, (E)-2-hexen-1-ol, and hexanal. With the exception of Cabernet Franc in 2019, the overall GLV contents of the six types generally increased during growth and development, peaking or stabilizing at harvest. And Sauvignon Blanc, Cabernet Gernischt, and Cabernet Sauvignon exhibited higher total contents among the varieties. PLS-DA analysis revealed 3-hexenal's high VIP scores across two years, underscoring its critical role in grape variety classification. Correlation analysis revealed a strong positive correlation between the levels of hexanal, 1-hexanol, (E)-2-hexen-1-ol, (Z)-3-hexenyl acetate, nonanal, and (E, E)-2,6-nonadienal and the expression of VvHPL and VvAAT genes in the LOX-HPL pathway. Specifically, VvHPL emerges as a potential candidate gene responsible for species–specific differences in GLV compounds. Comprehending the changing patterns in the biosynthesis and accumulation of GLVs offers viticulturists and enologists the opportunity to devise targeted strategies for improving the aromatic profile of grapes and wines. [ABSTRACT FROM AUTHOR]

During the manufacturing process of white wine, various physicochemical reactions can occur and can affect the quality of the finished product. For this reason, it is necessary to apply different treatments to minimize distinct factors such as protein instability and pinking phenomenon, which can affect the organoleptic properties of wines and their structure. In this work, a new method for the preparation of a sorbent-type material is presented through the fractional purification of native bentonite in three fractions (Na-BtF1, Na-BtF2, and Na-BtF3). Furthermore, the influence of the prepared sorbents on pH, conductivity, and amino nitrogen level was analyzed. The absorbents prepared and tested in wine solutions were characterized using the following physico-chemical methods: Brunauer–Emmett–Teller and Barrett–Joyner–Halenda (BET-BJH) method, X-ray diffraction (XRD) technique, and transform-coupled infrared spectroscopy Fourier with attenuated total reflection (FTIR-ATR). Following the analyses carried out on the retention of protein content and polyphenolic compounds, it was found that materials based on natural clay have suitable adsorption properties. [ABSTRACT FROM AUTHOR]

Studying non-Saccharomyces yeasts as bio-protectors can help find new alternatives to the chemical additive SO2 in winemaking. The present article evaluates the effect of two native yeasts, Candida oleophila and Candida boidinii, as potential bio-protectors to replace SO2 during the production of Sauvignon Blanc wine. Fermentation was conducted on simple and mixed inoculum at two concentrations, 1 × 106 and 1 × 107 cells/mL. We monitored the population of deterioration microorganisms, including lactic acid bacteria (LAB), acetic acid bacteria (AAB), and Brettanomyces bruxellensis (BB), apart from the final chemical and volatile composition of the wine. The results were compared with fermentations protected with SO2, where Candida oleophila yeast was more effective against lactic acid bacteria, whereas Candida boidinii was more effective against acetic acid bacteria and Brettanomyces bruxellensis; meanwhile, the fermentations with the initial inoculum of 1 × 107 cells/mL showed better results than those with an inoculum of 1 × 106 cells/mL. Bio-protector use did not negatively affect wine quality, equaling the effectiveness of SO2 for spoilage microorganism inhibition. This study reveals for the first time the potential of Candida oleophila and Candida boidinii yeasts as bio-protectors in microbiological wine stabilization. [ABSTRACT FROM AUTHOR]

This article deals with the analysis of the condensates which are formed from fermentation gases during the fermentation of grape must. The experiment was divided into two parts. In the first part, the evolution of the individual volatiles was monitored throughout the whole fermentation process of the Riesling variety. In the second part, the condensates from three different grape varieties (Riesling, Merlot, Sauvignon blanc) were investigated and the total content of the selected volatile substances was measured at the end of the fermentation. Attention was focused on the measurements using a GC-MS (gas chromatography-mass spectrometry) for the volatile substances: isoamyl alcohol, isobutyl alcohol, 1-propanol, ethyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, acetaldehyde, acetic acid, and acetoin. In addition, changes in the alcohol content of the condensate, with respect to the fermentation phase, were analysed. From the results of part 1, the quantity of the substances under investigation produced during fermentation was determined. The highest concentration of flavour compounds was during the fourth and fifth days of fermentation. The most dominant substance was isoamyl alcohol with a concentration of 1267 mg−1.The results of part 2 led to a comparison of the overall profile of volatiles between the varieties. The results showed that the condensates have both a high content of volatile substances and of alcohol. It was also shown that the Sauvignon blanc variant had the highest number of volatile compounds in the representation. The Merlot and Riesling variants were very similar. This product has an exceptionally high potential for further use in the wine or food industry. [ABSTRACT FROM AUTHOR]

Copper (Cu) is a naturally occurring metal with essential micronutrient properties. However, this metal might also pose increased adverse environmental and health risks due to industrial and agricultural activities. In Brazil, the maximum allowable concentration of Cu in drinking water is 2 mg/L. Despite this standard, the impact of such concentrations on aquatic organisms remains unexplored. This study aimed to evaluate the toxicity of CuSO4 using larval zebrafish at environmentally relevant concentrations. Zebrafish (Danio rerio) larvae at 72 hr post-fertilization (hpf) were exposed to nominal CuSO4 concentrations ranging from 0.16 to 48 mg/L to determine the median lethal concentration (LC50), established at 8.4 mg/L. Subsequently, non-lethal concentrations of 0.16, 0.32, or 1.6 mg/L were selected for assessing CuSO4 -induced toxicity. Morphological parameters, including body length, yolk sac area, and swim bladder area, were adversely affected by CuSO4 exposure, particularly at 1.6 mg/L (3.31 mm ±0.1, 0.192 mm2 ±0.01, and 0.01 mm2 ±0.05, respectively). In contrast, the control group exhibited values of 3.62 mm ±0.09, 0.136 mm2 ±0.013, and 0.3 mm2 ±0.06, respectively. Behavioral assays demonstrated impairments in escape response and swimming capacity, accompanied by increased levels of reactive oxygen species (ROS) and lipid peroxidation. In addition, decreased levels of non-protein thiols and reduced cellular viability were noted. Data demonstrated that exposure to CuSO4 at similar concentrations as those permitted in Brazil for Cu adversely altered morphological, biochemical, and behavioral endpoints in zebrafish larvae. This study suggests that the permissible Cu concentrations in Brazil need to be reevaluated, given the potential enhanced adverse health risks of exposure to environmental metal contamination. [ABSTRACT FROM AUTHOR]

Highlights: Pre-fermentative cryogenic treatments as a tool to increase the varietal thiol levels in Sauvignon blanc and Chenin blanc wines. Cryogenic pre treatment technologies as an innovative method for wine production. 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. [ABSTRACT FROM AUTHOR]

Summary: Wickerhamomyces anomalus D1‐4, a non‐Saccharomyces yeast known for its aroma production, offers a novel approach to improving the aroma and quality of mulberry wine. We employed various inoculation methods for fermenting mulberry wine and assessed its physicochemical, bioactive compounds, antioxidant activities, colour and aroma components. The results revealed that the addition of Wickerhamomyces anomalus D1‐4 to the fermentation led to a significant increase in the levels of alcohols, terpenes, nitrogen oxides and methyl in mulberry wine, especially, produced the characteristic isobutyl acetate and isopentyl hexanoate, and greatly increased the relative content of isopentyl acetate, isopentyl alcohol and phenylethyl alcohol. The sequential inoculation of Saccharomyces cerevisiae for 24 h followed by Wickerhamomyces anomalus D1‐4 fermented for 9 days was the best fermentation method for mulberry wine. Regarding colour, bioactive compounds and antioxidant activities, the fermentation was superior to other fermentations, and it was also able to maximise the aroma of mulberry wine and give it a strong floral and fruity aroma, especially higher ethyl hexanoate and ethyl octanoate. These findings demonstrate the unique fermentation characteristics of non‐Saccharomyces yeasts in enhancing the flavour and quality of mulberry wine. [ABSTRACT FROM AUTHOR]

In this study, changes in volatile compounds co-fermented by different Pichia kluyveri with Saccharomyces cerevisiae were analyzed using GC-IMS and compared with S. cerevisiae fermentation, to investigate the production of aroma in mulberry wine during the fermentation process. A total of 61 compounds were accurately identified, including 21 esters, 10 alcohols, 8 aldehydes, 6 ketones, and 19 other volatiles. Compared with the single strain fermentation (S. cerevisiae), the content of 2-methylpropyl acetate, allyl Isothiocyanate, ethyl crotonate, isobutyl propanoate, and butyl 2-methylbutanoate, co-fermentation groups (S. cerevisiae with different P. kluyveri) showed a significant decrease. Alcohols, aldehydes, ketones, and organic acid were lower in both the F(S-P1) and F(S-P2) groups than in the F(S) group throughout fermentation. The 2-methylpentanoic acid only was contained in the F(S) group. The co-fermentation with different P. kluyveri could also be well distinguished. The content of Benzaldehyde and 4-methylphenol in the F(S-P1) group was significantly lower than that in the F(S-P2) group. The PCA results revealed effective differentiation of mulberry wine fermented by different fermentation strains from GC-IMS. The result showed that P. kluyveri could establish a new flavor system for mulberry wine, which plays a crucial role in enhancing the flavor of fruit wine. [ABSTRACT FROM AUTHOR]