Macrowine 2021
IVES 9 IVES Conference Series 9 Using elicitors in different grape varieties. Effect over their phenolic composition

Using elicitors in different grape varieties. Effect over their phenolic composition

Abstract

Phenolic compounds are very important in crop plants and have been the subject of a large number of studies. Three main reasons can be cited for optimizing the level of phenolic compounds in crop plants: their physiological role in plants, their technological significance for food processing, and their nutritional characteristics1 Indeed, an enormous diversity of phenolic antioxidants is found in fruits and vegetables, and their presence and roles can be affected or modified by several pre- and postharvest cultural practices and/or food processing technologies (Ruiz-García et al. 2012, Goldman et al. 1999, Tudela et al. 2002). In winegrapes, the technological importance of phenolic compounds, mainly flavonoids, is well-known. They are responsible for the color of wines, especially anthocyanins (colored pigments responsible for the chromatic characteristics of red wines), tannins (responsible for the long-term stability of red wine color), and flavonols (compounds that may influence wine color through copigmentation). Moreover, they influence on other organoleptic properties such as astringency, bitterness, and body (Ruiz-García et al. 2012). Several techniques have been applied to improve the phenolic content of grapes. Leaving aside genetically modified plants, which are not allowed by the regulations of most countries, the most common techniques are related to cultural practices: pruning (González-Neves et al. 2002, Pérez-Lamela et al. 2007), cluster thinning (Fanzone et al. 2012, Soufleros et al. 2011), leaf removal (Gatti et al. 2012), and deficit irrigation (De la Hera et al. 2005, Koundouras et al. 2009). Another, more recent, technique for the same purpose is the use of elicitors, which are growing in interests. Elicitors are phytochemicals that do not kill pathogens themselves but trigger plant mechanisms that improve pathogen resistance, among them an increase in the levels of phenolic compounds (Vitallini et al. 2011), which are not only toxic to pathogens but also the precursors of disease-resistant material such as lignin (Pan and Liu 2011). This observed increase in phenolic compounds after the application of some elicitors justifies the interest in their application in fruits and vegetables. In our study, the effect of the application of benzhothiadiazol (BTH) and methyl jasmonate at veraison on the phenolic composition of grapes from three varieties (Monastrell, Cabernet Sauvignon and Merlot) was studied at harvest and after that, in wines at the end of alcoholic fermentation.The results showed that the effects of the treatments differed in the three varieties for the several phenolic compounds.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Rocio Gil

*IMIDA

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Partial dealcoholisation of red wine by reverse osmosis-evaporative perstraction: impact on wine composition

Around the world, the alcohol content of wine has been steadily increasing; partly as a consequence of climate change, but also due to improvements in viticultural management practices and winemaking techniques [1,2]. Concurrently, market demand for wines with lower alcohol levels has increased as consumers seek to reduce alcohol intake for social and/or health reasons [3]. As such, there is increasing demand for both innovative methods that allow winemakers to produce ‘reduced alcohol wines’ (RAW) and a better understanding of the impact of such methods on the composition of RAW. This study therefore aimed to investigate compositional changes in two red wines resulting from partial alcohol removal following treatment by one such method, involving a combination of reverse osmosis and evaporative perstraction (RO-EP).

How pressing techniques affect must composition and wine quality of Pinot blanc

This study investigates how the sensory profile of Pinot Blanc is affected from different maceration and pressing techniques. Grapes were sourced from four vineyards in the village Tramin in South Tyrol. For the experiment 200 kg of grapes from each vineyard site were hand picked the day before harvest for the commercial winery took place. Grapes were stored over night at 4°C, homogenized and processed in the experimental winery at Laimburg research centre the day after harvest. Four different pressing techniques were applied in duplicates of 100kg each.

New molecular evidence of wine yeast-bacteria interaction unraveled by untargeted metabolomic profiling

Bacterial malolactic fermentation (MLF) has a considerable impact on wine quality. The yeast strain used for primary fermentation can consistently stimulate (MLF+ phenotype) or inhibit (MLF- phenotype) malolactic bacteria and the MLF process as a function of numerous winemaking practices, but the molecular evidence behind still remains a mystery. In this study, such evidence was elucidated by the direct comparison of extracellular metabolic profiles of MLF+ and MLF- yeast phenotypes. Untargeted metabolomics combining ultrahigh-resolution FT-ICR-MS analysis, powerful machine learning methods and a comprehensive wine metabolite database, discovered around 800 putative biomarkers and 2500 unknown masses involved in phenotypic distinction.

Effect of concentration and competition between different fungicide residues on the adsorption efficiency of activated vegetal fibres for treatment of wine

Vineyards are strongly exposed to fungal diseases, attacks from insects and competition with weeds. Most treatments used on grape vines contain synthetic active substances, which may be transferred to the wine. Such pesticides have a negative image because many active substances are potential health hazards. A specific oenological treatment allowing the reduction of pesticide residues in wine based on activated vegetable fibres (AVF) is under examination by the International Organisation for Vine and Wine. This technique works efficiently and alters the wine only little (Lempereur et al. 2014).

Use of glutathione under different grape processing and winemaking conditions and its impact on the formation of sulfide off-flavors, colour, and sensory characteristics of Riesling, Sauvignon blanc, and Chardonnay

The use of glutathione (GSH) in winemaking has been legitimated recently, according to OIV resolutions OENO 445-2015 and OENO 446-2015 a maximum dose of 20 mg/L is now allowed to use in must and wine. Several studies have proven the benefits of GSH, predominantly in Sauvignon blanc. Thus, oxidative coloration of must and wine is limited, aroma compounds such as volatile thiols are preserved, and the development of ageing flavors such as sotolon and 2-aminoacetophenone is impeded. The protective effect may be explained by the high affinity of GSH to bind o-quinones which are formed during phenolic oxidation and which are known to initiate browning and other oxidative changes. Some researchers have proposed the hydroxycinnamic acid to GSH ratio (HGR) as an indicator of oxidation susceptibility of must and could show that lower ratios yielded lighter musts.