Insight into the role of magnetic nutrient solution on leaf morphology and biochemical attributes of Rasha grapevine (Vitis vinifera L.).

The growth, development, and morphology of plants are extremely affected by many internal and external factors. In this regard, plant nourishing solutions take the most impact. Nowadays, the magnetization of nutrient solutions has been recommended as a promising eco-friendly approach for improving the growth and development of plants. This study was designed to explore the potential of magnetic nutrient solutions in altering morphometric characteristics as well as some physiological and nutritional attributes of Rasha grapevines. Magnetic treatments included magnetized nutrient solution (MagS) and pre-magnetized water completed with nutrients (MagW + S) at magnetic field intensities (0.1 and 0.2 T). According to the results, the most considerable changes in leaf shape and size as well as fresh and dry weights were observed in the plants treated with MagS at 0.2 T. Also, MagS 0.2 had a significant effect on increasing photosynthetic pigments, content of total soluble carbohydrates and protein, and activity of antioxidant enzymes. The content of TNK, K, P, Fe, and Cu was considerably amplified by MagW + S 0.2. Overall, the magnetic solutions had favorable influences on physiological, nutritional state, and leaf morphology of grapevines possibly through alerting water and solution properties, mineral solubility, and phytohormones signalling.

Effect of Hormonization Treatment on Yield Quantity and Quality, Contents of Biologically Active Compounds, and Antioxidant Activity in 'Einset Seedless' Grapevine Fruits and Raisins.

In this study, we determined the effect of hormonization treatment on yield quantity and quality, content of biologically active compounds, and antioxidant activity in fruits and raisins of 'Einset Seedless' grapevine. Field studies were conducted in 2017 at Nobilis Vineyard (50°39' N; 21°34' E) in the Sandomierz Upland. Analytical studies were carried out in the Laboratory of the University of Life Sciences in Lublin. Hormonized fruits and raisins, which were dried at 40 °C in a food dryer for 7 days, were the experimental material. It was shown that the application of the hormonization treatment had a significant effect on yield size and quality. The hormonization treatment and the form of plant material analyzed had a significant effect on the content of biologically active compounds and the antioxidant activity in 'Einset Seedless' grapevine fruits and raisins. The concentration of applied gibberellic acid had a significant effect on the levels of acidity, content of anthocyanins, and antioxidant activity determined with the FRAP and DPPH methods. The application of the multivariate analysis technique showed that, in the fresh fruits and raisins, the level of biologically active compounds and antioxidant activity in the case of the 200 mg∙GA3∙L-1 concentration and in the control combination was similar but differed significantly in the case of the 300 mg∙GA3∙L-1 application.

Impact of grape variety, berry maturity and size on the extractability of skin polyphenols during model wine-like maceration experiments.

BACKGROUND: Skin cell walls modulate anthocyanin and tannin extraction from grape skins. However, relationships between the composition of alcohol-insoluble cell wall solids (AIS) and extraction are still unclear. Our objectives were to characterize the impact of variety, berry size and ripeness on skin AIS composition (polysaccharides, proteins) and polyphenol extraction during maceration. RESULTS: Grape skin composition and its impact on polyphenol extraction was compared for two varieties - Carignan and Grenache - with skins of berries sorted according to their size and density. Extractions were performed under model wine-like maceration conditions. Fresh skins had similar content of polymeric tannins, but strongly differed in their anthocyanin content (higher in Carignan and in the ripest berries) and composition (higher proportions in coumaroylated anthocyanins in Carignan). Anthocyanin extraction was proportionally much higher in Grenache, which was not just related to the Carignan's higher levels in coumaroylated anthocyanins. Chemical reactions decreased anthocyanin concentrations in solution for both varieties. Tannin extraction for Grenache was slightly higher and faster than for Carignan. Skin AISs differed slightly between the two varieties in their carbohydrate composition and protein content, but not between modalities. Polyphenol analyses in the precipitates evidenced at the end of the maceration and in residual skins highlighted differences between the two varieties and between berries with different ripeness. CONCLUSION: Structural information on the cell wall network and on its changes during maceration, along with a better understanding of the chemical reactions of anthocyanins and tannins, is needed to better relate grape and wine polyphenol composition. © 2020 Society of Chemical Industry.

Herbicide reduction through the use of weedmat undervine treatment and the lack of impact on the aromatic profile and volatile composition of Malbec wines.

Viticultural practices to control the undervine environment have relied on chemical herbicides. Herbicides usage has resulted in resistance by weeds, alterations in soil environments, as well as not meeting the needs of the organic market. Consequently, black and white weedmat was utilized to manage the undervine area over multiple vintages and its influence on the resultant wines examined. Apart from a difference in juice soluble solids, there was no impact on grape yield. In the 2017 vintage, black weedmat wines had the largest variation in aromatic profile when compared to control; additionally white weedmat was more closely related to the control. These differences had disappeared in the 2018 vintage with all wines having similar aromatic profile concentrations. Trained sensory panel could not discriminate treatment effects on wine flavor and aroma for either vintage. Ultimately, these findings support the use of weedmats in the viticulture setting to eliminate herbicide usage.

Improving micropropagation of some grape cultivars via boron, calcium and phosphate

BACKGROUND: An efficient regeneration protocol is a priority for the successful application of plant biotechnology. Grape nodal explants were used to develop a micropropagation protocol for Thompson Seedless and Taify cvs. Explants were cultured on MS medium supplemented with Kinetin or benzylaminopurine (BA) and indolebutyric acid (IBA). RESULTS: For both cultivars, axillary buds were grown, only, on a medium enriched with kinetin, moreover, shoot tip necrosis and callus formation were observed on Thompson Seedless cv. cultures grown on a medium with BA. Supplementing the growth medium with 100 mM (boron) B and 2.5 mM (calcium) Ca successfully help overcome these phenomena. The highest regenerated shoot numbers (14 and 6.2 explant 1 ) for Taify and Thompson Seedless cvs., respectively, were on media supplemented with 13.2 mM BA + 4.9 mM IBA and BA 13.2 mM + 5.8 mM IBA, respectively. Moreover, these media supported the developing shoots to have the heaviest dry weights (1.46 and 0.72 mg explant 1 ) for Taify and Thompson Seedless cvs., respectively. Thompson Seedless cv. regenerated shoot numbers and their dry weights were significantly increased by increasing the MS medium PO4 concentration. However, these two parameters were significantly decreased for Taify cv. Developing shoots were elongated and rooted on MS medium enriched with 4.9 mM, IBA 100 mM B and 2.5 mM Ca. Plantlets were acclimatized and successfully transferred to the greenhouse conditions. CONCLUSIONS: A novel promising protocol for Thomson Seedless and Taify cvs. micropropagation using single nodes has been developed.

Grapevine Cane Extracts: Raw Plant Material, Extraction Methods, Quantification, and Applications.

Grapevine canes are viticulture waste that is usually discarded without any further use. However, recent studies have shown that they contain significant concentrations of health-promoting compounds, such as stilbenes, secondary metabolites of plants produced as a response to biotic and abiotic stress from fungal disease or dryness. Stilbenes have been associated with antioxidant, anti-inflammatory, and anti-microbial properties and they have been tested as potential treatments of cardiovascular and neurological diseases, and even cancer, with promising results. Stilbenes have been described in the different genus of the Vitaceae family, the Vitis genera being one of the most widely studied due to its important applications and economic impact around the world. This review presents an in-depth study of the composition and concentration of stilbenes in grapevine canes. The results show that the concentration of stilbenes in grapevine canes is highly influenced by the Vitis genus and cultivar aspects (growing conditions, ultraviolet radiation, fungal attack, etc.). Different methods for extracting stilbenes from grapevine canes have been reviewed, and the extraction conditions have also been studied, underlining the advantages and disadvantages of each technique. After the stilbenes were extracted, they were analyzed to determine the stilbene composition and concentration. Analytical techniques have been employed with this aim, in most cases using liquid chromatography, coupled with others such as mass spectrometry and/or nuclear magnetic resonance to achieve the individual quantification. Finally, stilbene extracts may be applied in multiple fields based on their properties. The five most relevant are preservative, antifungal, insecticide, and biostimulant applications. The current state-of-the-art of the above applications and their prospects are discussed.

α-Glucosidase Inhibitory Activity of Tannat Grape Phenolic Extracts in Relation to Their Ripening Stages.

The present study aimed to screen grape extracts as novel α-glucosidase inhibitors to prevent type-2 diabetes and hyperglycemia. The total polyphenol content (TPC) was measured by Folin-Ciocalteu assay and the stilbene, anthocyanin and flavan-3-ol compounds were measured by Ultra High-Performance Liquid Chromatography coupled to Mass Spectrometry (UHPLC-MS). The α-glucosidase inhibitory of seed and skin Tannat grape extracts at four ripening stages were investigated. The highest TPC values were measured in seeds at the "veraison stage" (65.29 ± 5.33 g of Gallic Acid Equivalent (GAE) per kilogram of Fresh Weight (FW)). This was in accordance with the high flavan-3-ol contents measured for these two extracts (43.22 ± 2.59 and 45.45 ± 6.48 g/kg of seeds FW, respectively). The skin and seed extracts at the first stage of ripening exerted strong α-glucosidase inhibition, exceeding 95% (p < 0.05). A high linear correlation (R = 0.723, p ≤ 0.05) was observed between flavan-3-ol contents and the α-glucosidase inhibitory activity. The stilbene contents and this activity were moderately to strongly anti-correlated (R = -0.828, p ≤ 0.05 for trans-resveratrol). The enzyme kinetic studies revealed a mixed type of inhibition. This study brings promising results for the therapeutic potential of seed and skin Tannat grape extracts as a functional food product with anti-diabetic activity.

Polyphenol Profiles of Just Pruned Grapevine Canes from Wild Vitis Accessions and Vitis vinifera Cultivars.

Grapevine canes are an abundant byproduct of the wine industry. The stilbene contents of Vitis vinifera cultivars have been largely studied, but little is known about the stilbene contents of wild Vitis accessions. Moreover, there have only been few studies on the quantification of other phenolic compounds in just pruned grapevine canes. In our study, we investigated the polyphenol profile of 51 genotypes belonging to 15 Vitis spp. A total of 36 polyphenols (20 stilbenes, 6 flavanols, 7 flavonols, and 3 phenolic acids) were analyzed by high-performance liquid chromatography coupled with a triple quadrupole mass spectrometer. Our results suggest that some wild Vitis accessions could be of interest in terms of the concentration of bioactive polyphenols and that flavanols contribute significantly to the antioxidant activity of grapevine cane extracts. To the best of our knowledge, this is the most exhaustive study of the polyphenolic composition of grapevine canes of wild Vitis spp.

Auxin treatment of grapevine (Vitis vinifera L.) berries delays ripening onset by inhibiting cell expansion.

KEY MESSAGE: Auxin treatment of grape (Vitis vinifera L.) berries delays ripening by inducing changes in gene expression and cell wall metabolism and could combat some deleterious climate change effects. Auxins are inhibitors of grape berry ripening and their application may be useful to delay harvest to counter effects of climate change. However, little is known about how this delay occurs. The expression of 1892 genes was significantly changed compared to the control during a 48 h time-course where the auxin 1-naphthaleneacetic acid (NAA) was applied to pre-veraison grape berries. Principal component analysis showed that the control and auxin-treated samples were most different at 3 h post-treatment when approximately three times more genes were induced than repressed by NAA. There was considerable cross-talk between hormone pathways, particularly between those of auxin and ethylene. Decreased expression of genes encoding putative cell wall catabolic enzymes (including those involved with pectin) and increased expression of putative cellulose synthases indicated that auxins may preserve cell wall structure. This was confirmed by immunochemical labelling of berry sections using antibodies that detect homogalacturonan (LM19) and methyl-esterified homogalacturonan (LM20) and by labelling with the CMB3a cellulose-binding module. Comparison of the auxin-induced changes in gene expression with the pattern of these genes during berry ripening showed that the effect on transcription is a mix of changes that may specifically alter the progress of berry development in a targeted manner and others that could be considered as non-specific changes. Several lines of evidence suggest that cell wall changes and associated berry softening are the first steps in ripening and that delaying cell expansion can delay ripening providing a possible mechanism for the observed auxin effects.

Influence of berry ripeness on seed tannins extraction in wine.

The extraction of seed and skin tannins in wine has been investigated at three different grape maturity stages. For that, the tannins content and composition of seeds and skins at three different maturity stages were characterized. After that, an original approach of nanovinification was conducted. At each maturity stages, three winemaking modalities have been produced: (i) a control modality, (ii) a seed modality made of exclusively with seed and (iii) a skin modality made of exclusively with skins. The aim of this work is to describe and explain the seed tannins kinetics release in wine but also the impact of grape maturity on seed tannins extractability. For that, the evolution of seed and wine tannins content have been followed during the winemaking, from alcoholic fermentation to post-fermentative maceration.

Part I. Polyphenols composition and antioxidant potential during 'Blaufränkisch' grape maceration and red wine maturation, and the effects of trans-resveratrol addition.

The effects of extended maceration (13 days) were investigated for extraction of trans-resveratrol and other phenolics from grapes of cultivar 'Blaufränkisch', and then during the subsequent maturation of the wine (250 days). Total phenolics and three subgroups of phenolics were followed. The concentrations of total phenolics, total flavonoids, and total anthocyanins, but not of total nonflavonoids, increased with extended maceration, and then decreased after 250 days of maturation. Trans- and cis-resveratrol concentrations increased following extended maceration and maturation (6.5, 2.9 mg/L, respectively). The maximum polydatin concentration was reached after only 6 days of maceration (10.9 mg/L). The antioxidant potential of the must increased following extended maceration (12.3 mmol DPPH2/L), and then remained unchanged for the red wine after maturation. Addition of trans-resveratrol to the red wine and into model solutions showed increased solubility and stability of trans-resveratrol in the red wines over the model solutions. Minor increases in antioxidant potential and better stability of malvidin-3-glucoside were also seen.

Influence of pruning time and viral infection on stilbenoid levels in Pinot noir grape canes.

BACKGROUND: Grapevine canes represent a large source of waste derived from grape cultivation. In the present study, the effect of different processes of storage and different pruning times on the stilbene accumulation on Pinot noir canes was analyzed. Whether the alteration of the secondary metabolism accompanying leafroll symptom expressions could affect the stilbenoid accumulation in canes harvested at pruning time was also investigated. RESULTS: The maximum accumulation of trans-resveratrol and trans-piceatannol was obtained in canes harvested in October and dried at 40 °C. Even in grape canes harvested in October, November, and December and stored for different times at room temperature (20 ± 2 °C) a marked increase in trans-resveratrol and trans-piceatannol was evident, which reached a maximum at around 8 weeks of storage. A significant higher accumulation of trans-resveratrol and trans-piceatannol was also found in canes harvested from symptomatic plants compared to those harvested from asymptomatic plants for all the pruning times. CONCLUSION: This study confirms that the biosynthetic enzyme activities and, particularly, those involved in the stilbene pathway, persist during Pinot noir cane storage at different harvest times, with different storage times and conditions, and different sanitary status. © 2019 Society of Chemical Industry.

Gastroprotective effect of leaf extract of two varieties grapevine (Vitis vinifera L.) native wild and cultivar grown in North of Tunisia against the oxidative stress induced by ethanol in rats.

Context: Vitis vinifera leaves are traditionally used in Tunisian folk medicine to treat digestive pathologies.Objective: We aimed to compare the gastroprotective effects of hydromethanolic leaves extracts of wild and cultivated grapes accessions native of Tunisia.Materials and methods: The phytochemical analysis of grapevine leaves extracts was performed. The gastroprotective activity was evaluated by ethanol-induced gastric-ulcer in rats pre-treated with increased doses of the extracts or with the standard omeprazole. Index of gastric secretions (volume, pH and gastric mucus production), stomach wall histology and biochemical parameters were estimated for assessment of anti-secretory and gastroprotective effects of the extracts.Results: Pre-treatment with grapevine leaves extracts decreased significantly gastric volume, gastric mucosal damage and increased significantly gastric juice pH compared with the negative control group. The extracts prevented ethanol-induced decrease of the activity of antioxidant enzymes while the levels of malondialdehyde and of reduced glutathione were decreased significantly. Moreover, the most marked effect was observed at low doses of wild ecotype 'Nefza-I' extracts.Conclusion: The leaves of Vitis species might be suitable as a functional food for therapeutic purpose and demonstrates gastroprotective action in gastric lesions model. Both accessions exhibited gastroprotective effects, but wild 'Nefza-I' ecotype was more effective than cultivar 'Marsaoui'.

Transcriptome profiling of 'Kyoho' grape at different stages of berry development following 5-azaC treatment.

BACKGROUND: 5-Azacytidine (5-azaC) promotes the development of 'Kyoho' grape berry but the associated changes in gene expression have not been reported. In this study, we performed transcriptome analysis of grape berry at five developmental stages after 5-azaC treatment to elucidate the gene expression networks controlling berry ripening. RESULTS: The expression patterns of most genes across the time series were similar between the 5-azaC treatment and control groups. The number of differentially expressed genes (DEGs) at a given developmental stage ranged from 9 (A3_C3) to 690 (A5_C5). The results indicated that 5-azaC treatment had not very great influences on the expressions of most genes. Functional annotation of the DEGs revealed that they were mainly related to fruit softening, photosynthesis, protein phosphorylation, and heat stress. Eight modules showed high correlation with specific developmental stages and hub genes such as PEROXIDASE 4, CAFFEIC ACID 3-O-METHYLTRANSFERASE 1, and HISTONE-LYSINE N-METHYLTRANSFERASE EZA1 were identified by weighted gene correlation network analysis. CONCLUSIONS: 5-AzaC treatment alters the transcriptional profile of grape berry at different stages of development, which may involve changes in DNA methylation.

Metabolic and transcriptional changes associated with the use of Ascophyllum nodosum extracts as tools to improve the quality of wine grapes (Vitis vinifera cv. Sangiovese) and their tolerance to biotic stress.

BACKGROUND: Recent studies report that Ascophyllum nodosum extracts, once applied on the canopy of different crops, deliver positive effects, increasing yield, inducing tolerance to biotic stress, and improving the quality of products. However, the mechanisms of action are still unclear. In this research, vines subjected to multiple foliar applications of an A. nodosum extract (ANE) at label doses were compared with untreated vines (NTV) in accordance with a comparative approach. The investigation coupled a field experiment with a second trial conducted under semi-controlled conditions, to clarify the mechanisms of action involved. RESULTS: The biostimulant did not affect soluble solids or the acidity of grapes; instead, it improved their anthocyanin and phenolic concentrations and the respective profiles. At the time of harvest, anthocyanin, and phenolic concentration were increased by 10.4% and 14.5%, respectively, when compared to the NTV. These effects correlated with a specific modulation of genes involved in the flavonoid metabolic pathways. Moreover, grapes from ANE vines witnessed a significant reduction in the spreading of gray mold when they were either assessed in field conditions or in vitro, compared to the grapes of NTV vines. This was related to a significant upregulation of the defense-related genes of the plant. CONCLUSIONS: Overall, the results showed that A. nodosum extracts can be valuable tools in viticulture considering the emergence of challenging environmental conditions; hence, the regulation of specific metabolic pathways is the mechanism of action that leads to an increased tolerance of biotic stress and of changes in the content of grape metabolites. © 2019 Society of Chemical Industry.

The potential aroma and flavor compounds in Vitis sp. cv. Koshu and V. vinifera L. cv. Chardonnay under different environmental conditions.

BACKGROUND: Koshu, a hybrid of Vitis vinifera L. and V. davidii Foex, is the most popular indigenous cultivar for wine production in Japan. However, little is known about the potential aroma compounds it contains and how environmental factors affect these. In this study, we obtained comprehensive profiles of the volatile (both glycosidically bound and free) and phenolic compounds that occur in koshu berries, and compared these with similar profiles for V. vinifera cv. chardonnay. We then compared the response of these two cultivars to bunch shading and the ripening-related phytohormone abscisic acid (ABA). RESULTS: Koshu berries contained significantly higher concentrations of phenolic compounds, such as hydroxycinnamic acid derivatives, and some volatile phenols, such as 4-vinyl guaiacol and eugenol, than chardonnay berries, which are thought to contribute to the characteristics of koshu wine. In addition, koshu berries had a distinctly different terpenoid composition from chardonnay berries. Shading reduced the concentration of norisoprenoid in both cultivars, as well as several phenolic compounds, particularly their volatile derivatives in koshu berries. The exogenous application of ABA induced ripening and increased the concentrations of lipid derivatives, such as hexanol, octanol, 1-nonanol, and 1-octen-3-ol. Multivariate and discriminant analyses showed that the potential aroma and flavor compounds in the berries could be discriminated clearly based on cultivar and environmental cues, such as light exposure. CONCLUSION: The unique secondary metabolite profiles of koshu and their different responses to environmental factors could be valuable for developing various types of koshu wines and new cultivars with improved quality and cultural characteristics. © 2018 Society of Chemical Industry.

Leaf removal at veraison stage differentially affects qualitative attributes and bioactive composition of fresh and dehydrated grapes of two indigenous Cypriot cultivars.

BACKGROUND: The effect of leaf removal on postharvest performance of dehydrated grapes has been poorly analyzed. The aim of this study was to evaluate the effect of leaf removal at veraison stage on the metabolites of fresh and dehydrated grapes of two indigenous Cypriot cultivars ('Mavro' and 'Xynisteri'), which are destined for the production of 'Commandaria', a protected designation of origin (PDO) premium sweet wine. RESULTS: Leaf removal led to a reduction of soluble solids, titratable acidity, aroma potential and most of the phenolic groups in the musts of both cultivars. Dehydration led to a significant increase in all of these parameters in both cultivars, being more pronounced in cv. 'Mavro'. Interestingly, leaf removal indicated differential response in the dehydrated product of the cultivars examined; liquid chromatography (LC-DAD-qTOF-MS) data showed a significant decrease in phenolic compounds in 'Xynisteri' must (from 66.73 to 44.15 mg L-1 ), while 'Mavro' must registered similar values of phenolic compounds (from 94.78 to 96.72 mg L-1 ), but with a different distribution among phenolic groups. Intriguingly, flavonols and flavan-3-ols that present significant health-promoting properties showed higher concentrations in the must from dehydrated 'Mavro' grapes that were subjected to preharvest leaf removal. CONCLUSIONS: Leaf removal at veraison stage followed by sun drying differentially affected the chemical composition of the examined cultivars. This preharvest application followed by postharvest dehydration was beneficial for cv. 'Mavro', while this was not the case for cv. 'Xynisteri'. The effects of leaf removal in other developmental stages (i.e. pre/post bloom stage) need to be dissected with the ultimate goal of providing an end product with high bioactive content. © 2018 Society of Chemical Industry.

Alternating temperature in postharvest cooling treatment of 'Fiano' and 'Falanghina' grapes affects cell wall enzyme rate, berry softening and polyphenols.

BACKGROUND: In wine production, temperature control is important and cooling techniques are frequently used to cool down grape must. Grape compound extraction is facilitated by enzymatic cell wall disassembly. Accordingly, our hypothesis is that the use of an alternating temperature could favor enzyme activity and thus berry compound extraction. RESULTS: White wine grapes (cvs 'Falanghina' and 'Fiano') were kept at 4 °C or at an alternating temperature (4 and 20 °C with a 6-h interval) for 24 h. During the cooling treatment, berry skin resistance, berry firmness and native enzymes from the cell wall were analyzed; sugars, total acidity, malic acid and polyphenols were also measured. In 'Falanghina', α-d-glucosidase, ß-d-galactosidase and pectinmethylesterase increased in grape berry kept at an alternating temperature, and the berry firmness decreased and the polyphenol content was greater than in the other sample. In 'Fiano', polygalacturonase and pectinmethylesterase were responsable for berry softening and, overall, with an alternating temperature, the activity was higher and, consequently, sugars and polyphenol contents were higher. CONCLUSION: Instead of just cooling wine grape, a 24-h cycle of low and high temperature on wine grape after harvest could be used to increase cell wall enzyme activity and, consequently, decrease the berry firmness, favouring an increase in sugars and polyphenol contents. © 2018 Society of Chemical Industry.

Oak wood extracts applied to the grapevine. An alternative to obtain quality Garnacha wines.

Stomata in leaves regulate gas interchange and transpiration in the grapevine and through these pores both the penetration of aqueous solutions with nutrients as well as the excretion of products take place. The aim of this work was to study the influence of spraying the vineyard with toasted and untoasted oak extracts on the volatile composition and on the organoleptic quality of wine made from Garnacha grapes. The results were compared with a Garnacha control wine obtained with grapes sprayed with distilled water. The absorption of the compounds from the oak wood extracts was irregular and some of these compounds were modified by the yeast during fermentation so as to prevent fermentation problems. This was observed particularly in the case of furfural which were transformed into furfuryl alcohol by yeast in order to avoid irreversible cellular damage. On applying a discriminant analysis to the concentration of volatile compounds in the wines, the three treatments (control, toasted and untoasted oak extracts) were differentiate. The wine obtained from grapes treated with toasted oak extract showed a more intense wood aroma after 18months of bottle aging than the other wines. Likewise, spicy aromas were found to be more intense in the samples treated with some type of oak wood extracts.

Reducing copper use in the environment: the use of larixol and larixyl acetate to treat downy mildew caused by Plasmopara viticola in viticulture.

BACKGROUND: Plant extracts might provide sustainable alternatives to copper fungicides, which are still widely used despite their unfavourable ecotoxicological profile. Larch bark extract and its constituents, larixyl acetate and larixol, have been shown to be effective against grapevine downy mildew (Plasmopara viticola) under semi-controlled conditions. The aim of this study was to reduce the gap between innovation and the registration of a marketable product, namely to develop scalable extraction processes and to evaluate and optimise the performance of larch extracts under different conditions. RESULTS: Toxicologically and technically acceptable solvents like ethanol were used to extract the active compounds larixyl acetate and larixol from bark in sufficient amounts and their combined concentration could be increased by up to 39% by purification steps. The combined concentration of larixyl acetate and larixol from larch turpentine could be increased by up to 66%. The Minimal Inhibitory Concentration (MIC100 ) against P. viticola in vitro (6-23 µg mL-1 ) and the Effective Concentration (EC50 ) in planta under semi-controlled conditions (0.2-0.4 mg mL-1 ) were promising compared with other plant extracts. In vineyards, efficacies of larch extracts reached up to 68% in a stand-alone strategy and 84% in low-copper strategies. CONCLUSION: Larch extracts represent valid candidates for copper reduction in organic vineyards, and their development into a sustainable plant protection product might be feasible. © 2017 Society of Chemical Industry.