Macrowine 2021
IVES 9 IVES Conference Series 9 The moment of preharvest elicitor application influence its final effect on winegrapes quality

The moment of preharvest elicitor application influence its final effect on winegrapes quality

Abstract

Phenolic compounds are secondary metabolites of grapes. Plants produce a wide variety of this type of metabolites through diverse biosynthesis pathways and their production is sometimes a response to external stimuli, either environmental or biotic stresses. Some of them may act as chemical defenses against pathogens or herbivores and their synthesis is increased when the attack exists. However, it is remarkable that the synthesis of these interesting compounds can be activated even when the stimulus is not present, with the use of elicitors. These are substances that when applied exogenously trigger the biosynthetic pathways conducting to the synthesis of these defense compounds. Several studies have already demonstrated that the mechanism involved in the response of the plant after the use of elicitors implied an increased concentration of polyphenol compounds. In winegrapes, the elicitors are usually applied at veraison and the application is repeated some days after the first application. However, our studies showed that, when the evolution of phenolic compounds of the elicitor treated-grapes was followed during all the ripening period, the maximum concentration of phenolic compounds was achieved around two weeks after the treatment, decreasing from this moment and up to the harvest date. Therefore, we planned, for the first time, the application of the elicitor not at veraison but two weeks before the estimated harvest date and the phenolic content of these grapes at harvest were compared with control grapes (no elicitor treatment) and with grapes treated with the elicitor applied at veraison. The results showed that the treatment of grapes two weeks before harvest generally led to better results as regard the phenolic composition of grapes. The effect on the different phenolic families (mainly anthocyanins and tannins) are discussed as well as the differences found in the corresponding wines.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Encarna Gómez-Plaza*, Ana Bautista-Ortín, Luis Perez-Prieto, Marina Olivares

*University of Murcia

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

WineMetrics: A new approach to unveil the “wine-like aroma” chemical feature

“The Human being has an excellent ability to detect and discriminate odors but typically has great difficulty in identifying specific odorants”(1). Furthermore, “from a cognitive point of view the mechanism used to judge wines is closer to pattern recognition than descriptive analysis.” Therefore, when one wants to reveal the volatile “wine-like feature” pattern recognition techniques are required. Sensomics is one of the most recent “omics”, i.e. a holistic perspective of a complex system, which deals with the description of substances originated from microorganism metabolism that are “active” to human senses (2). Depicting the relevant volatile fraction in wines has been an ongoing task in recent decades to which several research groups have allocated important resources. The most common strategy has been the “target approach” in order to identify the “key odorants” for a given wine varietal.

On the losses of dissolved CO2 from laser-etched champagne glasses under standard tasting conditions

Under standard champagne tasting conditions, the complex interplay between the level of dissolved CO2 found in champagne, its temperature, the glass shape, and the bubbling rate, definitely impacts champagne tasting by modifying the neuro-physico-chemical mechanisms responsible for aroma release and flavor perception. Based on theoretical principles combining heterogeneous bubble nucleation, ascending bubble dynamics and mass transfer equations, a global model is proposed (depending on various parameters of both the wine and the glass itself), which quantitatively provides the progressive losses of dissolved CO2 from laser-etched champagne glasses.

New acylated flavonols identified in the grape skin of Vitis vinifera cv. Tannat and their wines

Flavonols are a class of flavonoid compounds derived from plant secondary metabolism. There they play different roles like antioxidants, internal regulators and UV screenings. In red wines, flavonols have increasingly received consideration by part of scientific and winemakers according their properties began to arise known. Among these stand out wine colour stabilization and their value as bioactive compounds. In this work the complete series of the acetylated and p-coumaroylated derivatives of the 3-O-glycosides of methoxylated flavonols, namely isorhamnetin, laricitrin and syringetin, have been identified in grapes and their respective wines from Vitis vinifera cv. Tannat.

Intelligent article to control the internal pressure in continue in bottles

An intelligent packaging might, among others, provide information and allow monitoring of the quality of the packed product or its surrounding environment. A recent project on micro-flow wine bottles closed with aluminium screw cap and tightness liner, highlighted the importance of monitoring the internal overpressure continuously, in real-time and at least for 72 hours, since the internal pressure on the tightness liner and the micro-flow are related. Real-time and continuous measurements are not the standard methods of measurement of the overpressure, yet. The most used equipment for the determination of the pressure in wine bottle is the aphrometer, a destructive device that supplies a single value of pressure.

Study of the content of amino acids and biogenic amines in sparkling red wines

The production of red sparkling wines is lower in Spain in comparison with the winemaking of white or rosé sparkling wines. In red sparkling wine processing it is essential to obtain suitable base wines that should have moderate alcohol content, high acidity, good color values, an adequate mouth-feel and a sweet tannin. Grapes for sparkling wine production have to be harvested at low maturity stages, with lower alcohol contents and higher acidities, which will that the phenolic maturity of the grapes is also low, showing green tannins. This paper analyses different treatments in order to minimize these inconveniences: cold maceration-prefermentation and delestage to elaborate the grapes with lower maturity, must nanofiltration, and the partial osmosis of the wines made from grapes with an adequate maturity degree.