Macrowine 2021
IVES 9 IVES Conference Series 9 The effect of Nitrogen and Sulphur foliar applications in hot climates

The effect of Nitrogen and Sulphur foliar applications in hot climates

Abstract

Vine nitrogen deficiency can negatively influence the aroma profile and ageing potential of white wines. Canopy management can alter vine microclimate, affect the nitrogen availability and influence the response of leaf senescence. Increasing the nitrogen availability to vines can increase the Yeast Assimilable Nitrogen (YAN) levels in harvested fruit and wine. Studies show that foliar nitrogen and sulphur applications at véraison, on low YAN Sauvignon blanc grapes have an effect on the level of amino acids (Jreij et al. 2009) and on S-containing compounds such as glutathione and thiols (Lacroux et al. 2008), which in turn can influence the formation of major volatiles and the aroma profile of the wine. The purpose of this study was to determine the effect of different foliar fertilization (spray applications) on the chemical and sensory composition of Vitis vinifera L. cv. Sauvignon blanc and Chenin blanc musts and wines. A Sauvignon blanc plot in the Elgin area and a Chenin blanc plot in the Somerset West area (Western Cape, South Africa), with naturally low nitrogen status, were sprayed three weeks and one week prior véraison. Urea (10 kg/ha) was used for the nitrogen application (N), elemental micronized sulphur (5 kg/ha) for the sulphur application (S), and combined urea (10 kg/ha) and elemental micronized sulphur (5 kg/ha) were used for the sulphur and nitrogen application (N+S). The applications were sprayed on the foliage of the vines and the control received no applications. Analysis of YAN, non-volatile and volatile compounds, namely volatile thiols, major volatiles, fatty acids, esters, alcohols, monoterpenes, and glutathione were done to evaluate the differences between the treatments. Sensory evaluation was performed by expert tasters using a free sorting method at two different stages of aging (3 months and 9 months after bottling). The YAN levels in the grapes were higher in the N and N+S applications compared to the control. The wines produced from the S and N+S applications contained more 3-mercapto-hexanol (3MH) and 3-mercaptohexyl-acetate (3MHA) compounds. Therefore with sufficient nitrogen and sulphur in the vines there may be an increase in aromatic quality and ageing potential of the Sauvignon blanc and Chenin blanc vines.

References
Jreij, R. et al., 2009. Combined effects of soil-applied and foliar-applied nitrogen on the nitrogen composition and distribution in water stressed Vitis Vinifera L. cv Sauvignon blanc grapes. J. Int. Sci. Vigne Vin, 43(4), pp.179–187. Lacroux, F. et al., 2008. Effect of foliar nitrogen and sulphur application on aromatic expression of Vitis vinifera L. cv. Sauvignon blanc. J Int Sci Vigne Vin, 42(3), pp.125–32.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Astrid Buica*, Aleta Bruwer, Wessel du Toit

*Stellenbosch University

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

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.

Micro-meteorological, compositional and transcriptional study of corvina grape color during ripening

Grape anthocyanin content and composition could affect the quality and the production strategies of red wines. Differences in the pigment composition modify the color properties in terms of hue, extractability and stability. Thus, for the production of a highly qualitative wine such as “Amarone”, variations in the pigment composition are not negligible. The aim of this work was the investigation of the anthocyanin profile changes during ripening in Corvina grapes, the main cultivar for the “Amarone” production. The experiment took place in 2015, in two vineyards located in Valpollicella (Italy).

Comprehensive two-dimensional gas chromatography coupled with Tof-MS, a powerful tool for analysis of the volatomes of grapes and wines

Comprehensive two-dimensional gas chromatography (GCxGC) has emerged as a powerful analytical technique for unraveling the volatile composition of complex matrices. This work will present three applications of GCxGC Tof-MS to the oenological field, aimed to identify novel biomarkers to be used in the quality control process of the wine industry. Comprehensive mapping of volatile compounds was conducted in a large sample of 70 sparkling wines, produced by 48 different wineries across 6 vintages and representative of the two main production areas for premium Italian sparkling wines (Franciacorta (FC) and Trentodoc (TN)), using HS-SPME followed by GCxGC-Tof-MS and multivariate analysis. Selection and identification of 196 putative biomarkers allowed clear separation of sparkling wines from FC and TN.

Interest and impact of PVP/PVI (Polyvinylpyrrolidone/ Polyvinylimidazole) on winemaking and final quality of wines

Céline Sparrow a, Christophe Morge a, a SOFRALAB SAS, 79, av. A.A. Thévenet – CS 11031 – 51530 Magenta, France Consumers’ health and security force authorities to limit, in wine as in others food industry products, the concentration in « dangerous » molecules. Therefore the legal limit in heavy metals keeps on decreasing. As per proof EU regulation just decrease the stain concentration in wine from 0,2 to 0,15 mg/l. Certain changes , such as sodium arsenite treatment in vines, disappearance of brass in wineries to the benefit of stainless steel, limit even more the concentration of heavy metals in wines. But the use of copper derivates in vines treatments is difficult to replace. In the case of wine and its elaboration, the problem is even more complex. Indeed, regulation forces the wine producers to control the concentration of certain heavy metals in final wines.

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.