Macrowine 2021
IVES 9 IVES Conference Series 9 Chemical markers in wine related to low levels of yeast available nitrogen in the grape

Chemical markers in wine related to low levels of yeast available nitrogen in the grape

Abstract

Nitrogen is an important nutrient of yeast and its low content in grape must is a major cause for sluggish fermentations. To prevent problems during fermentation, a supplementation of the must with ammonium salts or more complex nitrogen mixtures is practiced in the cellar. However this correction seems to improve only partially the quality of wine [1]. In fact, yeast is using nitrogen in many of its metabolic pathways and depending of the sort of the nitrogen source (ammonium or amino acids) it produces different flavor active compounds. A limitation in amino acids can lead to a change in the metabolic pathways of yeast and consequently alter wine quality. A better management of nitrogen fertilization of vineyards can significantly increase the quantity of yeast available nitrogen (YAN) in the grape and consequently the wine quality. A metabolomics study comparing Chasselas and Doral wines produced from grapes of two variants, nitrogen deficient culture versus supplemented with foliar urea, indicated several markers related to nitrogen supplementation of grapes [2]. Four substances from these potential markers were chosen for the present study: 2-phenylethanol, 2- plus 3-methylbutanol, succinic acid and prolin. The production of these compounds is known to be influenced by the nitrogen content of the must and they are in easily measurable concentrations in the wine. The objective of this work is to study the correlation between the concentration of YAN in must and the concentration of the four potential chemical markers in the wine using a significant number of samples ( > 130) including different grape varieties (13), harvests (2009-2014) and yeast types. The goal is to create a model for the retro-prediction of YAN concentration in the original must based on the chemical analysis of the wine. This information can be used by winemakers to optimize nitrogen fertilization of their vineyards. Wines produced in the cellar of AGROSCOPE using a standard protocol without addition of ammonium salt were used for this study. The concentration of YAN in the must was determined before the fermentation. The concentrations of the potential markers in the wine were measured for: the higher alcohols (2-phenylethanol, 2- and 3-methylbutanol) by GC-FID, for succinic acid by enzymatic method and for prolin by HPLC-MS. The four markers show a good correlation (R2 > 0.7) with YAN content in must. Grape variety and yeast variety strongly influence these correlations whereas harvest is less important. The distribution of YAN between ammonium and different individual amino acids explains the major part of the effect from the grape varieties. Reference 1. Bréant, L., Marti, G., Dienes-Nagy, Á., Zufferey, V., Rösti, J., Lorenzini, F., Gindro, K., Viret, O., Wolfender, J-L., In Vino Analytica Scientia 2013, Abstract Book, Poster 80 2. Lorenzini, F.; Vuichard, F.; Revue Suisse de Viticulture Arboriculture Horticulture, 44 (2012), pp 96-103

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Agnes Dienes-Nagy*, Carole Koestel, Fabrice Lorenzini, Johannes Rösti

*AGROSCOPE

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Evidence for terroir effect associated with botrytisation relatively to compounds implicated in typical aromas of noble rot sweet wines

Recent studies have demonstrated the role of certain lactones, particularly 2-nonen-4-olide, and volatile thiols (3-sulfanylhexan-1-ol) in the over ripped aromas of noble rot sweet wines (Stamatopoulos et al. 2014ab). These compounds are partly formed during the maturation and under the activity of B. cinerea on grapes. This research was carried out in the vineyard of Sauternes with aim to better understand their genesis depending on the grape over-ripening on two different soil types during 3 vintages. Thus, the study was conducted, with the Sémillon grape, during vintages 2012, 2014 & 2015, at 4 stages of over-maturation of the grapes (healthy, pourri plein, pourri roti, pourri roti + 15 days) considering two vineyard plots with different soil characteristics (calcosol & peyrosol) planted with the 315 Sémillon clone and grafted on 101-14 rootstock respectively in 1981 and 1980 and cultivated with the same vineyard management. Volatile lactones were assayed by liquid-liquid extraction followed by GC/MS analysis and the precursors of 3-sulfanylhexanol by an adaptation of the method by Capone et al. 2010 (SPE-
UPLC/FTMS).

Identification, quantification and organoleptic impact of « dried fruit » molecular markers in Merlot and Cabernet Sauvignon grapes and in red wines

The aromas found in young Bordeaux red wines made with Merlot and Cabernet Sauvignon suggest a complex mixture of aromas of fresh red fruits such as cherry or blackberry for Merlot, and strawberry or blackcurrant for Cabernet Sauvignon. The aromas of these wines are closely linked with the maturity of the grapes. The climate change that has occurred during the last decade in Bordeaux has induced changes in the ripening conditions of grape berries. It is now widely admitted that over-ripening of the berries during hot and dry summers results in the development of characteristic flavors reminiscent of cooked fruits (fig, prune). The presence of these overriding odors found in both musts and young wines affects the quality and subtlety of the wine flavor and may shorten its shelf life.

Molecular cloning and characterization of UDP-glucose: furaneol glucosyltransferase gene from Japanese

2,5-Dimethyl-4-hydroxy-3(2H)-furanone (furaneol) is an important aroma compound in fruits, such as pineapple and strawberry, and is reported to contribute to the strawberry-like note in some wines. Several grapevine species are used in winemaking, and furaneol is one of the characteristic aroma compounds in wines made from American grape (Vitis labrusca) and its hybrid grape, similar to methyl anthranilate. Muscat Bailey A is a hybrid grape variety [V. labrusca (Bailey) x V. vinifera (Muscat Hamburg)], and its wine is one of the most popular in Japan. The inclusion of Muscat Bailey A in the ‘International List of Vine and Varieties and their Synonyms’ managed by the ‘International Organisation of Vine and Wine (OIV)’ in 2013 has further fueled its popularity among winemakers and researchers worldwide.

Glutathione content evolution during spontaneous alcoholic fermentations of Sangiovese grapes

Glutathione is a tripeptide (γ-Glu-Cys-Gly), which can occur in grapes, in must and in wine prevalently in the reduced form as well as in the oxidized form as glutathione disulfide. The importance of the reduced form of glutathione lies in its antioxidant activity. In must, it limits browning by reducing o-quinones produced by polyphenol oxidase activity on hydroxycinnamic acids; in wine, it exerts a protective effect on various aromatic compounds. Glutathione concentration in wine is lower than in grape juice and variable as it depends on several factors, ranging from the native content of grapes to winemaking technique.

A combination of biotechnology tools and coopers elements for an alternative the addition of SO2 at the end of the malolactic fermentation in red wines or at the “mutage” for the “liquoreux” wines

In red wines the post-MLF SO2 addition is an essential event. It is also the case for the “mutage” during the elaboration of the “liquoreux”. At these moments SO2 plays an antimicrobial action and an antioxidant effect. But at current pH of wines, ensuring a powerful molecular SO2 has become very difficult. Recent work on Brettanomyces strains have also shown that some strains are resistant up to 1.2 mg / L of molecular SO2. It’s also the case of the some Saccharomuces or Zygosaccharomyces strains suitable to re-ferment “liquoreux” wines after the “mutage”.