SummaryThe addition of enological tannins is a practice admitted and widely used to improve wine phenolic compositions. Although wine ageing is an oxidative process involving phenolic compounds and acetaldehyde production and consumption, the effect of enological tannins on the acetaldehyde and chromatic and phenolic changes of a red wine during oxidation is still not known. In this study, three enological tannins preparations containing gallotannins GT, ellagitannins ET and condensed tannins CT were added to a young commercial Lambrusco red wine in order to obtain wines with three different phenolic compositions. Samples were then treated with hydrogen peroxide to trigger oxidation. All added tannins have determined a production of acetaldehyde greater than control. Acetaldehyde was then consumed in 30 days. The samples treated with CT and ET showed, after oxidation, an increase in colour intensity, determined as the sum of 420, 520 and 620 nm absorbances. A simultaneously increase in polymeric pigments was detected. No significant variation of the Saliva Precipitation Index (SPI), an index useful to give an indirect measure of wine astringency, was observed after 30 days of treatment of CT and ET samples. Results highlight that the addition of CT and ET can help to stabilise colour without affecting wine reactivity towards salivary proteins. A significant role of acetaldehyde has been even detected. These are the first data showing the effect of different enological tannins on the production and consumption of acetaldehyde formation during an oxidation process.
<p>In the Mediterranean region, climate models forecast an increase in temperature and irregularities in the precipitation patterns which are a challenge for viticulture. The number, type, intensity and duration of stressors induce specific morpho-physiological responses which are cultivar-specific and are reflected on grape yield and quality. A major challenge for vines in southern Mediterranean area is to invest resources to construct leaves capable of efficiently converting carbon into biomass, while controlling evapotranspiration losses, as well as maintaining a balance between vegetative growth and reproduction. Plants have to harmonize structure and function to achieve efficient physiological processes and use of resources. Although it is not clear whether plant anatomical structure is the bottleneck for efficient functioning or vice versa, it is recognized that tissue growth and photosynthesis cannot be decoupled. Therefore, the knowledge of the plasticity in the coordination between morpho-anatomical and eco-physiological traits in vines is needed to forecast how vineyards would respond to climate changes. Moreover, the impact of climate change depends on pedo-climatic spatial variability, and it can be either buffered or intensified by vineyard management.</p> <p>Within this framework, the aim of this study was to evaluate the combined effect of two types of canopy management (double guyot and double guyot flipped) and three treatments of soil management (cover crops, natural coverage, and soil tillage) on the coordination of morpho-anatomical and eco-physiological traits in the grapevine cultivar 'Greco' (<em>Vitis vinifera</em> L. subsp. <em>vinifera</em>), autochthonous and widely cultivated in the Campania Region (southern Italy). The field trials were conducted at the Feudi di San Gregorio winery premises in southern Italy, within the GREASE project, funded by the Campania Region through the Rural Development Programme 2014-2020, with the general goal of improving grapevine productivity and resilience for the sustainable management of vineyards.</p> <p>The status of vines was monitored over three years by applying a multidisciplinary approach allowing the analysis of vines behavior at the single plant- and whole-vineyard levels. Indeed, the growth and the eco-physiological traits of vines were monitored by measuring biometrical parameters, leaf gas-exchanges, chlorophyll a fluorescence emission, and leaf water potentials. Leaves were also sampled to quantify carbon stable isotopes as well as functional anatomical parameters (e.g. parenchyma, stomata and vein traits) linked to the efficiency of gas-exchanges and water flow. Proximal sensing techniques were applied to monitor the whole vineyard performances. The meteorological data and soil water content were collected through weather stations and time-domain reflectometry (TDR) technique.</p> <p>The overall analysis of results showed that the effect of different canopy and soil management is strongly mediated by inter-and intra-annual variability of climatic factors. From a methodological point of view, the multidisciplinary approach proved to be fundamental to go in-depth in the cause-effect relations and mechanisms for vines acclimation. Only a deep understanding of such acclimation mechanisms can furnish the keys to optimize the utilization of the information collected through the novel proximal technologies, for the design of vineyard management strategies to improve yield and quality still assuring environmental sustainability.</p>
<p>Climate change, causing increasing warming and drought in Mediterranean area, is year by year determining grapevine yield and berry quality reductions, with particular extent in some of the autochthonous grape varieties, as Greco grapevine, cultivated in the Campania Region (southern Italy) and used alone or blend in many quality label wines. Since pedo-climatic conditions affect vineyard productivity and grape quality, the adoption of adequate cultivation techniques, such as soil and canopy management, can support vineyard in counteracting climate change effects, improving grape yield and berry quality, thus allowing to obtain highly valuable wines. The evaluation of the Greco grapes quality by the analysis of primary metabolites of the grape and the secondary ones, with an oenological impact responsible for the organoleptic quality and the longevity of the white wines, is pivotal for understanding whether the adopted cultivation practices might mitigate the negative effects deriving from long-lasting exposure of grapes to drought and/or rainy periods which may determine the onset of organoleptic defects in the wines.</p> <p>In the framework of the Rural Development Programme 2014-2020, Campania Region funded the Grease project to contribute to the main topic of improving grapevine productivity, resource use efficiency and resilience for the sustainable management of vineyards.</p> <p>Within the general objective of the Grease project, the aim of this study was to evaluate how different combinations of main cultivation practices, as vine canopy and soil management, can allow to exert a balanced&#160; vegetative and reproductive growth that enhances grape and wine quality, improving farm profitability.</p> <p>The three-year trial was carried out in a Greco experimental vineyard of Feudi di San Gregorio winery in southern Italy (Avellino, Campania region), aiming to analyze the effects of three soil management practices (cover crops, natural coverage, and soil tillage) and two vine training systems (double guyot and double guyot flipped) on yield, berry and must quality in three vintages. &#160;The meteorological data and soil water content were collected through weather stations and time-domain reflectometry (TDR) technique.</p> <p>At harvest yield components were determined and berry quality was evaluated by measuring soluble solids, pH, titratable acidity, malic acid, phenolics, assimilable nitrogen etc. Apart usual chemical analytical methodologies, spectrophotometric and chromatographic techniques were used to determine phenolic composition of grapes and wines. Microvinifications were also performed to evaluate the variability of oenological traits under different combination of soil and canopy management.</p> <p>A great effect of year on primary and secondary metabolites were detected. Soluble solids and total phenolic compounds increased passing from 2020, 2021 and 2023 while a clear trend for titratable acidity and pH was not observed due to a wide variation in malic acid content. &#160;Among soil management practices natural coverage and cover crops resulted in grapes with lower content of soluble solids while the soil tillage determined a lower content of phenolic compounds and hydroxycinnamic acids in grapes. In two years, soil tillage determined higher content of assimilable nitrogen in grapes probably because a lower competition for nitrogen occurred. Trends observed in grapes were confirmed in wines.</p>
<p>Leaf water potential (LWP) is widely used to assess plant water status and it is commonly used by growers to make immediate crop and water management decisions. However, LWP measurement via direct method presents challenges as it is labour, time intensive and represents leaf-level conditions for sampling of small vineyard block. An alternative approach is using pigment concentration as a proxy for the canopy&#8217;s water status. Spectral data methods have been applied to monitor and evaluate crops&#8217; biophysical variables. In this study, a model to predict LWP using via UAS equipped with a VIS-NIR multispectral camera and trained machine learning algorithm, is developed and tested. &#160;The model was tested on three dates in 2020 in a commercial vineyard in the Tufo Wine Region. Three modelling approaches (partial least square regression PLSR, support vector machine SVM, artificial neural network ANN) and two input datasets (combining spectral data and spectral vegetation indices) were used to estimate LWP. All approaches predicted LWP-based on spectral data classified from high to low; the results were consistent in direct proportion to the laboratory results and performed the best results. This research shows the potential for estimating LWP at a vineyard scale based on UAS information, represents a good and relatively cheap solution to assess plant status spatial distribution and therefore it could provide a direct way to achieve precise agricultural vineyard.</p>
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