In Vitro Toxicity Assessment of Stilbene Extract for Its Potential Use as Antioxidant in the Wine Industry

The reduction of sulfur dioxide in wine is a consumer’s demand, considering the allergic effects that may occur in people who are sensitive to it. Stilbenes are candidates of great interest for this purpose because of their antioxidant/antimicrobial activities and health properties, and also because they are naturally found in the grapevine. In the present study, the in vitro toxicity of an extract from grapevine shoots (with a stilbene richness of 45.4%) was assessed in two human cell lines. Significant damage was observed from 30 μg/mL after 24 h, and 40 µg/mL after 48 h of exposure. Similarly, the ultrastructural study revealed a significant impairment of cell growing. The extract was able to protect cells against an induced oxidative stress at all concentrations studied. In view of the promising results, a more exhaustive toxicological assessment of the extract is needed to confirm the safety of its further use as additive in wine.España,Ministerio de Economía, Industria y Competitividad and INIA for the financial support for this project (RTA2015-00005-C02-02

Wood Waste from Fruit Trees: Biomolecules and Their Applications in Agri-Food Industry

In the European Union (EU), a total of 11,301,345 hectares are dedicated to the cultivation of fruit trees, mainly olive orchards, grapevines, nut trees (almond, walnut, chestnut, hazelnut, and pistachio), apple and pear trees, stone fruit trees (peach, nectarine, apricot, cherry, and plum), and citrus fruit trees (orange, clementine, satsuma, mandarin, lemon, grapefruit, and pomelo). Pruning these trees, together with plantation removal to a lesser extent, produces a huge amount of wood waste. A theoretical calculation of the wood waste in the European Union estimates approximately 2 and 25 million tons from wood plantation removal and pruning, respectively, per year. This wood waste is usually destroyed by in-field burning or crushing into the soil, which result in no direct economic benefits. However, wood from tree pruning, which is enriched in high added-value mol-ecules, offers a wide spectrum of possibilities for its valorization. This review focuses on the contri-bution of wood waste to both sustainability and the circular economy, considering its use not only as biomass but also as a potential source of bioactive compounds. The main bioactive compounds found in wood are polyphenols, terpenes, polysaccharides, organic compounds, fatty acids, and alkaloids. Polyphenols are the most ubiquitous compounds in wood. Large amounts of hydroxyty-rosol (up to 25 g/kg dw), resveratrol (up to 66 g/kg dw), protocatechuic acid (up to 16.4 g/kg), and proanthocyanins (8.5 g/kg dw) have been found in the wood from olive trees, grapevines, almond trees and plum trees, respectively. The bioactivity of these compounds has been demonstrated at lower concentrations, mainly in vitro studies. Bioactive compounds present antioxidant, antimicro-bial, antifungal, biostimulant, anti-inflammatory, cardioprotective, and anticarcinogenic properties, among others. Therefore, wood extracts might have several applications in agriculture, medicine, and the food, pharmaceutical, nutraceutical, and cosmetics industries. For example, olive tree wood extract reduced thrombin-induced platelet aggregation in vitro; grapevine tree wood extract acts a preservative in wine, replacing SO2; chestnut tree wood extract has antifungal properties on post-harvest pathogens in vitro; and stone tree wood extracts are used for aging both wines and brandies. Moreover, the use of wood waste contributes to the move towards both a more sustainable development and a circular economy.Ministerio de Economía, Industria y Competitividad RTA2015-00005-C02-0

Time course of l-tryptophan metabolites when fermenting natural grape musts: effect of inoculation treatments and cultivar on the occurrence of melatonin and related indolic compounds

Background and Aims:Tryptophan is involved in the formation of bioactive compounds, such as melatonin (MEL) and3-indoleacetic acid (3-IAA), by yeast. Melatonin is a neurohormone whose occurrence in wine has been widely reported inrecent years. The occurrence, however, of MEL and other indolic compounds related to tryptophan metabolism by wineyeast strains has been scarcely reported in grape musts. This work examined the occurrence of these compounds during thealcoholic fermentation (AF) of musts from seven grape cultivars, Corredera, Chardonnay, Moscatel, Palomino Fino, Sau-vignon Blanc, Tempranillo and Vijiriega.Methods and Results:Must was fermented with threeSaccharomyces cerevisiaestrains and then in two cases an additionalsequential inoculation with the non-SaccharomycesyeastTorulaspora delbrueckiiwas carried out. Fermented must samples wereanalysed by UHPLC/HRMS to determine the concentration of:L-tryptophan, 5-hydroxytryptophan, 5-hydroxytryptamine,N-acetyl-5-hydroxytryptamine, MEL, 3-IAA, tryptamine, tryptophol andL-tryptophan ethyl ester. The profile of indoliccompounds during AF with the Aroma White strain depended on the cultivar. The yeast strain did not influence the profile ofindolic compounds; instead, fermentation time was found to be a more influential factor.Conclusions:The production of indolic compounds during the AF depends largely on the cultivar used and the day of fer-mentation on natural grape musts.Significance of the Study:This is thefirst study that quantifies 5-hydroxytryptophan andN-acetyl-5-hydroxytryptamineduring the AF of grape must. The occurrence of compounds with bioactive potential, for example 3-IAA and ML, during fer-mentation with commercial yeast strains is also described.Ministerio de Economía y Competitividad de España - AGL2013-47300-C3-2-R, 2014–16 y AGL2016-77505-C3-2-R, 2017–1

Impact of preharvest and postharvest treatment combinations on increase of stilbene content in grape

Aims : Stilbene-enriched grape is an interesting new food product with numerous health-promoting properties, mainly due to its high added-value compound content, notably resveratrol. The aim of this study was to evaluate the effects of different elicitors, alone or in combination with ultraviolet C light (UVC) postharvest treatment, on stilbene concentration in grapes. Methods and results : Three preharvest treatments were tested, namely benzothiadiazole, (BTH), methyl jasmonate (MEJA) and chitosan (CHIT). After harvesting, these treatments were combined with UVC postharvest treatment. The stilbene extraction method was validated method. Moreover, and grape quality was evaluated. Of the preharvest treatments, only BTH significantly increased trans-resveratrol concentration in grape, but this appears to be linked to a ripening delay. When pre- and postharvest treatments were combined, only the MEJA-UVC combination was successful in reducing by three days the day of maximum induction of stilbenes (trans resveratrol and piceatannol). Conclusion: The MEJA-UVC combination reached similar grape trans-resveratrol contents than UVC alone, but additionally the time to reach maximum trans-resveratrol after the UVC treatment was reduced by three days and therefore grape quality was preserved. Significance and impact of the study: The achieved results provide a potential treatment combination that allows functional grapes to be obtained in a shorter period than with UVC light alone, making it more applicable

Cytotoxicity studies of a stilbene extract and its main components intended to be used as preservative in the wine industry

The use of stilbenes has been proposed as an alternative to sulfur dioxide in wine. Provided the feasibility from a technological approach, the cytotoxicity of an extract from grapevine shoots containing a stilbene richness of 99% (ST-99 extract) was assessed in the human cell lines HepG2 and Caco-2. In addition, the effects of the main stilbenes found in ST-99, trans-resveratrol and trans-ε-viniferin were studied, as well as its mixture. Similar cytotoxic effects were obtained in the exposures to trans-ε-viniferin, ST-99 and the mixture; however, trans-resveratrol alone exerted less toxicity. When HepG2 cells were exposed to trans-ε-viniferin, ST-99 and the mixture, the mean effective concentration (EC50) were 28.28 ± 2.15, 31.91 ± 1.55 and 29.47 ± 3.54 µg/mL, respectively. However, in the exposure to trans-resveratrol, the EC50 was higher 50 µg/mL. The morphological study evidenced damage at ultrastructural level in HepG2 cells, highlighting the inhibition of cell proliferation and the induction of apoptosis. The type of interaction produced by trans-ε-viniferin and trans-resveratrol mixtures was assessed by an isobologram analysis using the CalcuSyn software, evidencing an antagonist effect. These data comprise a starting point in the toxicological assessment; further studies are needed in this field to assure the safety of the extract ST-99.Ministerio de Economía, Industria y Competitividad and INIA (RTA2015-00005-C02-02)Bordeaux Metabolome Facility and MetaboHUB (ANR-11-INBS-0010 project

Explorando el potencial bioestimulante del alga invasora Rugulopterix okamurae en vid

Trabajo presentado en las IV Jornadas del Grupo de Viticultura de la Sociedad Española de Ciencias Hortícolas, celebradas en Pamplona (España), del 26 al 28 de octubre de 202

Estilbenos como una alternativa sostenible al anhídrido sulfuroso en vinos

Resumen El anhídrido sulfuroso (SO2) es el conservante más empleado en la industria agroalimentaria y enológica por sus propiedades antioxidantes y antimicrobianas. Sin embargo, también es un alérgeno que puede provocar problemas de salud en personas sensibles a él. Por otra parte, la madera de poda procedente de los viñedos es uno de los principales subproductos de la industria vitivinícola, con un volumen estimado entre 2 y 4 toneladas por hectárea y año. Este subproducto vitícola contiene polifenoles, entre otros estilbenos bioactivos con propiedades saludables. En el presente trabajo se ha elaborado y caracterizado un extracto puro de estilbenos obtenido a partir de madera de poda de la vid, para utilizarlo como alternativa sostenible al SO2 en la elaboración de vinos blancos y rosados. Se evaluó el impacto del extracto sobre la calidad de los vinos (parámetros enológicos, color, compuestos fenólicos y perfil sensorial) tanto en el embotellado y a los doce meses del embotellado. En paralelo se evaluó la posible toxicidad del extracto. Los resultados obtenidos concluyen que el extracto puro de estilbenos, obtenido a partir de madera de poda de la vid, puede proponerse como alternativa natural y sostenible al empleo de SO2 en la vinificación de vinos blancos y rosados. Además, el extracto no mostró toxicidad ni in vitro ni in vivo

Valorization of grape stems

The wine industry produces large amounts of grape stem byproducts, which have been described as a natural source of polyphenols. In the present study, an extract from grape stems was evaluated for its antioxidant and antimicrobial activities in model wine to determine its potential capacity to replace and/or reduce SO2 in winemaking. Additionally, its possible effects on aroma were studied. Grape stem extract (STE) showed high antioxidant activity and it can be proposed as an energetic antioxidant. Its antimicrobial activity was compared to that of SO2. STE showed a lower inhibitory effect than SO2 for Saccharomyces cerevisiae, Hanseniaspora uvarum, Dekkera bruxellensis and Pediococcus damnosus whereas STE seems to be more efficient against Candida stellata and Botryotinia fuckeliana. GC–olfactometry analysis of STE showed that its most important odorants are naturally present in wines, and thus olfactometric profile modifications in wine, after STE addition, could appear quantitatively but not qualitatively. It can be concluded that grape stems are compounds with a low sourcing cost, high antioxidant activity and good antimicrobial properties.Ciencias de la AlimentaciónFarmaciaMedicin

Efficacy of olive oil mill extract in replacing sulfur dioxide in wine model

Olive oil industry produces high amounts of olive mill solid waste. These have been described as natural source of hydroxytyrosol, which shows high antioxidant and antimicrobial properties joint to healthpromoting effects. In the present work, an olive mill solid waste extract dissolved in model wine was evaluated to determine its potential capacity to replace and/or reduce sulfur dioxide in winemaking. Olive oil mill extract is a potent antioxidant of biological origin. The extract resulted in 4 and 40 mmol/L Trolox/mg extract by DPPH and ORAC respectively. Its antimicrobial activity was approaching to that of SO2 for Hanseniaspora uvarum, Candida stellata, Lactobacillus plantarum, Pediococcus damnosus and Acetobacter aceti, higher for Oenococcus oeni and lower for Dekkera bruxellensis and Botryotinia fuckeliana. Additionally, GC-olfactometry analysis showed that the most important odorants from the extract are naturally present in wines. However, some odorant zones might be significantly increased in wine after extract addition. It can be concluded that olive mill solid waste extracts is a source of bioactive compounds of low cost, with high antioxidant activity and good antimicrobial properties.Ciencias de la Alimentació

Holistic understanding of the response of grapevines to foliar application of seaweed extracts

Viticulture is highly dependent on phytochemicals to maintain good vineyard health. However, to reduce their accumulation in the environment, green regulations are driving the development of eco-friendly strategies. In this respect, seaweeds have proven to be one of the marine resources with the highest potential as plant protective agents, representing an environmentally-friendly alternative approach for sustainable wine production. The current work follows an interdisciplinary framework to evaluate the capacity of Ulva ohnoi and Rugulopteryx okamurae seaweeds to induce defense mechanisms in grapevine plants. To our knowledge, this is the first study to evaluate Rugulopteryx okamurae as a biostimulator . This macroalgae is relevant since it is an invasive species on the Atlantic and Mediterranean coast causing incalculable economic and environmental burdens. Four extracts (UL1, UL2, RU1 and RU2 developed from Ulva and Rugulopteryx, respectively) were foliar applied to Tempranillo plants cultivated under greenhouse conditions. UL1 and RU2 stood out for their capacity to induce defense genes, such as a PR10, PAL, STS48 and GST1, mainly 24 hours after the first application. The increased expression level of these genes agreed with i) an increase in trans-piceid and trans-resveratrol content, mainly in the RU2 treated leaves, and, ii) an increase in jasmonic acid and decrease in salicylic acid. Moreover, an induction of the activity of the antioxidant enzymes was observed at the end of the experiment, with an increase in superoxide dismutase and catalase in the RU2-treated leaves in particular. Interestingly, while foliar fungal diversity was not influenced by the treatments, alga extract amendment modified fungal composition, RU2 application enriching the content of various groups known for their biocontrol activity. Overall, the results evidenced the capacity of Rugulopteryx okamurae for grapevine biostimulation, inducing the activation of several secondary metabolite pathways and promoting the abundance of beneficial microbiota involved in grapevine protection. While further studies are needed to unravel the bioactive compound(s) involved, including conducting field experiments etc., the current findings are the first steps towards the inclusion of Rugulopteryx okamurae in a circular scheme that would reduce its accumulation on the coast and benefit the viticulture sector at the same time