Search Results (111)

Protein instability in white wines is mainly caused by pathogenesis-related (PR) proteins that survive winemaking and can form haze in bottle. Because PR-protein synthesis is modulated by vine stress, this study evaluated whether unmanned aerial vehicle (UAV) multispectral imagery and NDVI-based vigor zoning can be used as early predictors of protein instability in commercial Chardonnay and Sauvignon Blanc wines. High-resolution multispectral images were acquired over two seasons (2023–2024) in two vineyards, and three vigor zones (high, medium, low) were delineated from the NDVI at the individual vine scale. A total of 180 georeferenced vines were sampled, and musts were analyzed for thaumatin-like proteins and chitinases via RP-HPLC. Separate microvinifications were carried out for each vigor zone and cultivar, and the resulting wines were evaluated for protein instability (heat test) and bentonite requirements. Low-vigor vines consistently produced musts with higher PR-protein concentrations, greater turbidity after heating, and higher bentonite demand than high-vigor vines, with stronger effects in Sauvignon Blanc. These vigor-dependent patterns were stable across vintages, despite contrasting seasonal conditions. Linear discriminant analysis using NDVI, PR-protein content, turbidity, and bentonite dosage correctly separated vigor classes. Overall, UAV NDVI–based vigor zoning provided a robust, non-destructive tool for identifying vineyard zones with increased risk of protein instability. This approach supports precision enology by enabling site-specific stabilization strategies that reduce overtreatment with bentonite and preserve white wine quality. Full article

The valorization of grapevine pruning residues through pyrolysis provides a sustainable approach to agricultural waste management, producing biochar with agricultural use potential and carbon sink functionality. This study investigated pruning residues from 12 grapevine cultivars to evaluate the cultivar effects on biochar properties. Samples were collected along the Croatian coast from Istria to Dalmatia and included six indigenous cultivars (Malvazija istarska, Pošip, Maraština, Teran, Plavina, and Plavac mali) and six introduced cultivars (Chardonnay, Pinot blanc, Sauvignon blanc, Merlot, Cabernet Sauvignon, and Syrah). For each cultivar, residues were collected from three distinct vineyards with three replicates per vineyard. Pyrolysis was conducted in a muffle furnace at 400 °C. The pruning residues showed acidic pH (4.79–5.45), moderate electrical conductivity (1694–2390 µS cm⁻¹), and ash contents of 2.65–3.49% among all cultivars. Significant differences were observed among cultivars in residue carbon content and ash fraction, which were reflected in the resulting biochar. Biochar yield ranged from 32% to 35%, while pH values were alkaline, ranging from 10.20 to 11.13. Total carbon increased from 43.77 to 45.36% in grapevine-pruning residues to 65.88–71.57% in biochar. FT-IR spectra revealed cultivar-dependent variation in aromatic C=C intensification, while SEM analysis indicated differences in pore abundance and surface area (1.63–4.13 m² g⁻¹) between cultivars. These results demonstrate that carbon-dense cultivars produced biochars with greater structural stability, indicating enhanced resistance to decomposition. Spectroscopic and microscopic analyses consistently showed increased aromatic condensation, reduced aliphatic functionality, and greater porosity following pyrolysis. These cultivar-dependent differences highlight pruning residues as a chemically heterogeneous but predictable feedstock, with biochar properties primarily governed by the intrinsic characteristics of the source material. Full article

Grapevine water relations are increasingly influenced by drought under climate change, with significant implications for yield, fruit composition and wine quality. Stable isotopes of hydrogen, oxygen, carbon and nitrogen (δ²H, δ¹⁸O, δ¹³C and δ¹⁵N) provide sensitive tracers of plant water sources and physiological responses to stress. Here, we combined dual water isotopes (δ²H, δ¹⁸O), carbon and nitrogen isotopes (δ¹³C, δ¹⁵N), and high-resolution micrometeorological/soil observations to diagnose drought dynamics in Vitis vinifera cv. Sauvignon blanc (Orlești, Romania; 2023–2024). Dual-isotope relationships delineated progressive evaporative enrichment along the soil–plant–atmosphere continuum, with slopes LMWL ≈ 6.41 > stem ≈ 5.0 > leaf ≈ 2.2, consistent with kinetic fractionation during transpiration (leaf) superimposed on source-water signals (stem). Weekly leaf δ¹⁸O covaried strongly with relative humidity (RH; r = −0.69) and evapotranspiration (ET; r = +0.56), confirming atmospheric control of short-term enrichment, while stem isotopes showed buffered responses to soil water. We integrated Δ¹⁸O (leaf–stem), RH, ET, and soil matric potential at 60 cm (Soil₆₀) into an Isotopic Drought Index (IDI), which captured the onset, intensity, and persistence of the July–August 2024 drought (IDI_0–100 > 90; RH < 60%, ET > 40 mm wk⁻¹, Soil₆₀ > 100 cb). Carbon and nitrogen isotopes provided complementary, integrative diagnostics: δ¹³C increased (less negative) with drought (r = −0.52 with RH; +0.49 with IDI), reflecting higher intrinsic water-use efficiency, whereas δ¹⁵N rose with soil dryness and IDI (leaf: r ≈ +0.48 with Soil₆₀; +0.42 with IDI), indicating constraints on N acquisition and enhanced internal remobilization. Together, multi-isotope and environmental data yield a mechanistic, field-validated framework linking atmospheric demand and edaphic limitation to vine physiological and biogeochemical responses and demonstrate the operational value of an isotope-informed drought index for precision viticulture. Full article

Wine samples (72) of different types (white, rose and red), dry, originating from different regions of Greece (Northern Greece, Central Greece, Peloponnese, Aegean Islands, and Crete), were analyzed for Ochratoxin A (OTA) presence. Wine samples, originating from Greek (Assyrtiko and Xinomavro) and international (Syrah and Sauvignon blanc) noble grapevine varieties vintaged from 2020 to 2023, were analyzed using a modified QuEChERS extraction protocol followed by HPLC with a fluorescence detector to detect and quantify OTA. Moreover, conventional oenological parameters were measured according to OIV official methods, and climatic conditions of the regions of concern were retrieved. Interestingly, in general, OTA contaminated wines showed low concentrations (<2.0 μg/L). The highest concentrations of OTA were detected in Sauvignon blanc (7.5 μg/L) regarding the white wines and Xinomavro (2.07 μg/L) regarding the red ones. In addition, the highest OTA concentrations were recorded in wines produced in areas either with high mean annual temperatures, like Viotia (24.16 °C) for white and Larissa (23.9 °C) for red wines, or with high rainfall between May and September (Larissa 69.76 mm) for white wines. Consequently, it was observed that concentrations of OTA in wine are relatively higher in the warmer regions of Greece compared to the cooler areas. The effect of climate change on vines and mycotoxin presence in wine needs urgent consideration by well-constructed modelling studies and efficient interpretation of existing data. The evaluation of OTA presence in grape products originating from various cultivars and regions is imperative not only for providing crucial data to predict its fate under climate change, but also to ascertain the potential risk of human exposure to this chemical compound. Full article

An increasing trend toward alternative methods in grapevine protection is evident, diverging from conventional chemical approaches. Biostimulants, such as chitosan hydrochloride, are compounds able to elicit the synthesis of plants’ metabolites, leading to an increase in their natural defence mechanism. Some of these metabolites could potentially impact wine sensory properties such as colour, mouthfeel, and aroma. This study investigates the effect of chitosan hydrochloride treatment on Sauvignon blanc vines, isolating impacts on plant, grape, and wine levels. Using a randomized block design with 74 potted plants grown in a glasshouse, the study found that foliar chitosan application did not affect plant growth or phenolic compound accumulation in the leaves. Conversely, it significantly decreased polyphenol oxidase (PPO) activity and increased antioxidant activity and polyphenolic content in grape berries. Treated berries exhibited doubled protein content, less thaumatin-like proteins, and more β-glucanases and chitinases than control grapes. Microvinifications revealed that wines from treated grapes had higher total polyphenols, polysaccharides, Abs 320 nm values, and total proteins than control wines. These preliminary results suggest that chitosan application affects key grape metabolites with potential implications for wine quality, warranting further investigation. Full article

Chemical control of weeds with the herbicide glyphosate under vines in the vineyards is currently easy, effective, and cheap. There are currently no completely equivalent alternative herbicides or suitable mechanical control methods that have the same efficacy in suppressing weeds under vines in vineyards as glyphosate. Therefore, in this research, we tested two alternative technologies for controlling weeds under the vines as a counterweight to the predominant control approach with the herbicide glyphosate: (1) chemical control with pelargonic acid, acetic acid, and the plant extract-based fertilizer Stopeco^® with herbicidal action, and (2) mechanical control with a combined tool consisting of a rotary star tiller and finger weeder. A comparative analysis was conducted on time and fuel consumption, the extent of the carbon footprint, grape yield, and quality, which showed that the tested alternative methods of weed control were not comparable to the herbicide glyphosate in terms of effectiveness in weed suppression but were comparable at grape yield. In our trial, at the number of treatments we performed, differences in environmental footprint between different treatments were significant (glyphosate variant 10.55–11.21 gha anno⁻¹; other variants 7.48–8.08 gha anno⁻¹). Alternative mechanical and chemical methods need to be applied at least three to four times a year to achieve results comparable to those from two applications of glyphosate. For this reason, it is possible that, in the case of a slightly increased number of passes by mechanical tools or a slightly increased number of sprayings with alternative preparations to reach the efficacy level of glyphosate treatments, the foot print parameter, CO₂ emissions and global warming potential (GWP) parameter in alternative treatments would no longer be more favorable than when using the herbicide glyphosate twice a year. Full article

Incrocio Bruni 54 is a little-known white grape variety developed in the Marche region (Italy) from a cross between Verdicchio and Sauvignon Blanc to combine aromatic freshness with structure. In light of the growing interest in minor and autochthonous cultivars, this study provides the first comprehensive chemical characterization of the aroma profile of Incrocio Bruni 54 wines. Seventeen commercial wines were analyzed for varietal compounds, such as terpenes, norisoprenoids, volatile thiols, methyl salicylate and its glycosides, and fermentative compounds, including esters, alcohols, acids, phenols, aldehydes, and ketones, using GC-MS/MS and LC-MS/MS. Odor activity value (OAV) calculations revealed an aroma profile dominated by ethyl esters, such as ethyl caproate and isopentyl acetate, β-damascenone, 4-vinylguaiacol, TDN, and the volatile thiols 3MH and 4MMP, imparting fruity, floral, spicy, and tropical notes. Comparison with datasets of 246 Italian monovarietal white wines and related sub-datasets composed of Verdicchio and Lugana showed significantly higher concentrations of 3MH and free methyl salicylate in Incrocio Bruni 54, but markedly lower levels of glycosylated methyl salicylate forms, suggesting a greater expression of this odorant in young wines balanced by a lower potential over aging. These findings highlight the distinctive aromatic fingerprint of Incrocio Bruni 54, combining parental traits with unique sensory potential, and support its knowledge and valorization in wine production. Full article

This study investigates the effects of rising temperatures on photosynthetic efficiency and stress tolerance in major Greek grapevine cultivars by using Sauvignon Blanc and Merlot as references. Muscat and Assyrtiko displayed the most heat-tolerant photosynthetic apparatus among the white cultivars, while Mavrodafni was the most heat-tolerant among the red ones, by effectively managing excess light energy. Sauvignon Blanc, although exhibiting heat susceptibility, maintained high photosystem II (PSII) functionality under heat stress by activating photoprotective mechanisms. Savvatiano and Agiorgitiko were more vulnerable to photo-oxidative stress above 35 °C, while Agiorgitiko maintained a functional photosynthetic apparatus, even at 40 °C, by shifting to a more photoprotective strategy. In contrast, Merlot, despite its resistance to photo-oxidative stress, lacked photoprotective investment, resulting in suppressed PSII under heat stress. Moschofilero was the most susceptible cultivar to photo-oxidative stress. Leaf morphological traits also contributed to heat stress tolerance, with smaller, thicker leaves facilitating thermoregulation. The present results provide important insights into specific responses to heat stress of major Greek grapevine cultivars. This knowledge may aid in selecting heat-tolerant genotypes and optimizing vineyard site selection, thereby enhancing the sustainability and climate resilience of viticulture. Full article

The quality of white wine is related to sensory attributes like color, odor and taste. This study focused mainly on taste attributes of white wines. The research hypothesis was to find out if taste-related attributes alone, determined by sensory experiment, could discriminate Chardonnay versus non-Chardonnay wines. Sensory analyses were performed with a trained panel on commercial white wines made from single varieties. Black glasses and nose clips were used to remove sensory interference and to first assess only taste attributes. Initial tests were then performed to evaluate the possibility to discriminate against Chardonnay wines only due to taste. In a second series of experiments, Rate All That Apply (RATA) experiments were performed in a set of Chardonnay versus non-Chardonnay wines. An initial sensory experiment revealed that some of the Chardonnay wines could be discriminated against by taste only but that recognition by using olfaction was more powerful which confirmed our research hypothesis in part. The second series of RATA sensory analysis revealed that some specific descriptors such as fat, salt, bitter and acid are involved in the taste discrimination of Chardonnay versus non-Chardonnay wines, especially with Sauvignon Blanc wines. These findings suggest that while modal sensory approach remains more robust for varietal identification, taste alone offers some discriminatory power. Full article

This study investigates the impact of climate change on key physiological parameters of Greek indigenous grapevine cultivars (Savvatiano, Muscat, Assyrtiko, Mavrodafni, Moschofilero, and Agiorgitiko), using Sauvignon blanc and Merlot as benchmarks. The aim was to identify genotypes with higher photosynthetic dynamics and water use efficiency (WUE) under heat stress and to examine the role of CO₂ enrichment in modulating these responses. Gas exchange measurements showed that short-term exposure to elevated CO₂ (e[CO₂]) (i.e., 700 ppm) enhanced photosynthesis by 37–64%, 77–89%, and 18–68% under control, moderate, and severe heat-stress regimes (23, 35, and 40 °C), respectively. CO₂ enrichment also improved WUE by 61–122%, 96–138%, and 11–63%, with the greatest benefits at 30–33 °C, depending on genotype. Cultivars with strong CO₂-saturated photosynthetic capacity and small stomata, such as Sauvignon blanc and Mavrodafni, showed greater photosynthetic stimulation and WUE improvement from CO₂ elevation. Stomatal traits influenced photosynthesis under ambient CO₂ (a[CO₂]) but not under e[CO₂]. Of the white varieties examined, Sauvignon blanc and Savvatiano showed the best performance under combined e[CO₂] and heat stress, while Assyrtiko and Muscat adapted better to high temperatures at a[CO₂]. Among red cultivars, Mavrodafni showed the highest photosynthetic efficiency at both CO₂ conditions, even under heat stress. The present findings indicate that grapevine varieties exhibit differential responses to elevated temperature and CO₂ levels. A comprehensive understanding of grapevine responses to stress conditions is therefore essential for the selection of cultivars with enhanced adaptation to climate change. Full article

Entomopathogenic fungi (EPF) are substantial biocontrol agents reducing the populations of economically important pests in numerous crops. Recent findings indicate that their role in agroecosystems is more complex and extends to affecting plant physiology and growth. This study examined the effects of Beauveria bassiana and Isaria fumosorosea, as well as Salicylic acid (SA), on physiological parameters of grapevine (Vitis vinifera cv. Sauvignon Blanc). Additionally, the impact of SA on spore germination and pathogenicity of EPF against larvae of the European grapevine moth (Lobesia botrana) was tested. Foliar application of EPF was found to increase the electron transport rate (ETR) from PSII to PSI, indicating higher photosynthetic activity compared to control plants. EPF also elevated the transpiration rate (E) and stomatal conductance (gs). In contrast, SA treatments decreased E and gs, while the high dose (10 mM) exhibited reduced Fv/Fm value, accompanied by phytotoxic spots on leaves. Spore germination of both fungi was significantly reduced only by the SA concentration of 2 mM, while 0.5 and 1 mM did not affect germination. Combination EPF and SA treatments presented the highest larval mortality of L. botrana (87.5% at 28 °C and 77.5% at 24 °C for B. bassiana and I. fumosorosea, respectively). However, SA reduced larval mycosis in most cases. Overall, the results suggest that EPF and SA can be co-applied and included in vineyard integrated strategies to support grapevine health. Full article

Sparging is a common technique in wineries that consists of injecting a gas, normally before bottling, in order to displace the dissolved oxygen in the wine and prevent oxidation. The objective of this study was to examine the effect of sparging on wines with three different levels of dissolved oxygen and the evolution of the chemical parameters in a bottle. This study was carried out on two white wines, Verdejo and Sauvignon blanc. The results indicated that sparging did not immediately affect the chemical parameters in the white wines, but it did affect their evolution in bottles, with a greater effect found in the Sauvignon blanc wines than in the Verdejo wines. Sparging, which was carried out to remove oxygen from the wines, had a protective effect on their color during the time in the bottles, preventing a more rapid decrease in free SO₂. The effect of sparging on the volatile compounds of the wines was more evident in the Sauvignon blanc wines, which showed a reduction in their content, possibly due to carry-over when the N₂ was applied. With regard to the effect of sparging on the sensory profile of the wines, no immediate effect was found. However, the wines with a DO content of 6 and 8.4 mg/L to which sparging was applied evolved better in the bottles than the deoxygenation wines, showing more fruity notes and fewer oxidized and phenolic aromas (mainly in the Verdejo wines). Full article

The wine industry aims to reduce pesticide use by utilizing disease-resistant grape varieties, although their oenological potential remains underexplored. This study aimed to evaluate their oenological potential compared to traditional ones. Musts from resistant (Souvignier Gris, Sauvignac, Voltis, and Floreal) and traditional (Chardonnay, Sauvignon Blanc, and Viognier) varieties were fermented at laboratory scale with online CO₂ monitoring, and two yeasts were used to study varietal responses to yeast impact. Wines were analyzed for metabolites from central carbon metabolism, aromas (varietal thiols, ethyl esters, acetate esters, and higher alcohols), and phenolic compounds (hydroxybenzoic acids, hydroxycinnamic acids, flavan-3-ols, and flavonols) using (U)HPLC methods. Principal component analysis (PCA) of all variables revealed Souvignier Gris grouped with a Sauvignon Blanc sample, partially due to varietal thiols. PCA of aromas (PC1: 37.7%, PC2: 17.8%) showed that Souvignier Gris and Sauvignac exhibited similar behavior to Sauvignon Blanc. The heat map of 19 phenolics showed Sauvignac and Sauvignon Blanc clustered, with lower phenolic abundance. This preliminary work contributes to a detailed characterization of the oenological potential of these new varieties and constitutes an essential step in identifying which traditional and well-known varieties they resemble. This will then enable the recommendation of cellar itineraries adapted to their profile. Full article

The production of winter wines in Southeastern Brazil represents a relatively recent but expanding viticultural approach, with increasing adoption across diverse wine-growing regions. This system relies on the double-pruning technique, which allows for the harvest of grapes during the dry and cooler winter season, favoring a greater accumulation of sugars, acids, and phenolic compounds. This study aimed to characterize the phenological stages, thermal requirements, yield, and fruit quality of the fine wine grape cultivars ‘Sauvignon Blanc’, ‘Merlot’, ‘Tannat’, ‘Pinot Noir’, ‘Malbec’, and ‘Cabernet Sauvignon’ under double-pruning management in a subtropical climate. The vineyard was established in 2020, and two production cycles were evaluated (2022/2023 and 2023/2024). Significant differences in the duration of phenological stages were observed among cultivars, ranging from 146 to 172 days from pruning to harvest. The accumulated thermal demand was higher in the first cycle, with a mean of 1476.9 growing degree days (GDD) across cultivars. The results demonstrate the potential of Vitis vinifera L. cultivars managed with double pruning for high-quality wine production under subtropical conditions, supporting the viability of expanding viticulture in the state of São Paulo. ‘Cabernet Sauvignon’ and ‘Sauvignon Blanc’ showed the highest yields, reaching 3.03 and 2.75 kg per plant, respectively, with productivity values of up to 10.8 t ha⁻¹. ‘Tannat’ stood out for its high sugar accumulation (23.4 °Brix), while ‘Merlot’ exhibited the highest phenolic (234.9 mg 100 g⁻¹) and flavonoid (15.3 mg 100 g⁻¹) contents. These results highlight the enological potential of the evaluated cultivars and confirm the efficiency of the double-pruning system in improving grape composition and wine quality in non-traditional viticultural regions. Full article

This study evaluates the impact of grape variety and harvesting method—manual versus mechanized—on must composition, wine quality, and economic performance in the Târnave viticultural area of Romania. Four grape varieties—Pinot Noir, Sauvignon Blanc, Fetească Regală, and Muscat Ottonel—were analyzed. Manual harvesting increased reducing sugars by 4.3–5.1 g/L and decreased titratable acidity by 0.6–0.8 g/L, particularly in Pinot Noir and Muscat Ottonel. Alcohol content was higher by 0.4–0.6 vol% in manually harvested samples, and dry extract increased by 1.0–1.3 g/L. Mechanized harvesting raised catechin concentrations by 15–19 mg/L due to enhanced skin maceration, but also slightly elevated volatile acidity (by ~0.1 g/L). From an economic perspective, labor cost was reduced from 480 lei/ton (approx. EUR 96) for manual harvesting to 120 lei/ton (approx. EUR 24) with mechanization. Fuel and maintenance costs for mechanized equipment averaged 85 lei/ha (EUR 17), and equipment depreciation was estimated at 100 lei/ton (EUR 20). The total harvesting cost per ton decreased from 480–520 lei to 300–320 lei (approx. EUR 96 to EUR 64), representing a ~38% reduction. The study supports a hybrid approach: manual harvesting for sensitive or premium cultivars, and mechanization for cost-efficient, large-scale production, aligning wine quality goals with economic sustainability. Full article