Macrowine 2021
IVES 9 IVES Conference Series 9 Evaluation of three alternative strategies for the long-term remediation of reductive off-odours in wines

Evaluation of three alternative strategies for the long-term remediation of reductive off-odours in wines

Abstract

Sulfur-like off-odours are a problem caused by the presence of free forms of volatile sulphur compounds (VSCs). H2S is the most frequently found above its odour threshold (1-10 µg/L), followed by methanethiol (MeSH). Recent evidences showed that the usual treatments to eliminate VSCs from wine e.g.: addition of Cu salts or micro-oxygenation only delay the occurrence of reductive off-odours. (Vela et al., 2017, 2018) The present work aims to assess the effectiveness of three alternative remediation strategies on the removal of VSCs:

1.- intensive oxygenation in the presence of a 3-mercaptopropyl-functionalized adsorbent (MPS);

2.- purging out with N2 the wine stored in reductive conditions; and,

3.- incubation with lees. The treatment with MPS consisted in the addition of 1 mM (of -SH groups) of the functionalized adsorbent to two different wines.

They were further saturated with air and, after three days, were centrifuged and analysed. The purge with N2 was applied to two different wines, which had been previously stored during 2 weeks at 50ºC under anoxia. They were purged at 100 mL/min during 60 min and analysed after the treatment. For lees treatment, three different types of lees were studied: fresh active lees, fresh inactive lees and commercial inactivated dry yeast. They were added (3,3 g/L) to wines with reductive off-odour, then they were incubated for 16 weeks at 25ºC, with weekly agitation. After the incubation, the wines were centrifugated to remove the lees. VSCs and redox potential of wines were analysed by GC-SCD (Ontañón et al., 2019) before and after each essay. Additionally, after the treatments an accelerated reductive aging was carried out (incubation at 50ºC under anoxia for 2 weeks) to assess the long-term effect of the treatments. Intensive oxygenation was very effective (-85% H2S BR after treatment and accelerated aging in both cases). Purge treatment was effective only in the short time, removing completely free H2S free and -70% BR-H2S. However, it was not effective in the long-term. The use of inactivated dry yeast was ineffective. The use of active or inactive fresh lees was effective only in some cases. In conclusion, oxidation with MPS provides the most effective treatment; purging was effective only in the short-term; and treatments with lees were not conclusive. Further studies to assess side effects of oxidation with MPS on wine characteristics should be carried out.

DOI:

Publication date: September 13, 2021

Issue: Macrowine 2021

Type: Article

Authors

Diego Sánchez-Gimeno

Diego Sánchez-Gimeno, Laboratory  of Aroma Analsis and Oenology (LAAE), Instituto Agroalimentario de Aragón –IA2-; Departamento de Química Analítica, Facultad de Ciencias, Universidad de Zaragoza, 50009. Zaragoza, Spain,Ignacio Ontañon, LAAE, –IA2- Universidad de Zaragoza Vicente Ferreira, LAAE, –IA2- Universidad de Zaragoza

Contact the author

Keywords

reduction, off-odours, vscs, lees, purge

Citation

Related articles…

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Effects of mechanical leafing and deficit irrigation on Cabernet Sauvignon grown in warm climate of California

San Joaquin Valley accounts for 40% of wine grape acreage and produces 70% of wine grape in California. Fruit quality is one of most important factors which impact the economical sustainability of farming wine grapes in this region. Due to the recent drought and expected labor cost increase, the wine industry is thrilled to understand how to improve fruit quality while maintaining the yield with less water and labor input. The present study aims to study the interactive effects of mechanical leafing and deficit irrigation on yield and berry compositions of Cabernet Sauvignon grown in warm climate of California.

The effects of cane girdling on berry texture properties and the concentration of some aroma compounds in three table grape cultivars

The marketability of the table grapes is highly influenced by the consumer demand; therefore the market value of the table grapes is mainly characterized by its berry size, colour, taste and texture. Girdling could cause accumulation of several components in plants above the ringing of the phloem including clusters and resulting improved maturity. The aim of the experiments was to examine the effect of girdling on berry texture characteristics and aroma concentration.

Application of a fluorescence-based method to evaluate the ripening process and quality of Pinot Blanc grape

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Different yield regulation strategies in semi-minimal-pruned hedge (SMPH) and impact on bunch architecture

Yields in the novel viticulture training system Semi-Minimal-Pruned Hedge (SMPH) are generally higher compared to the traditional Vertical Shoot Positioning (VSP). Excessive yields have a negative impact on the vine and wine quality, which can result in substantial losses in yield in subsequent vintages (alternate bearing) or penalties in fruit quality. Therefore yield regulation is essential. The bunch architecture in SMPH differs from VSP. Generally there is a higher amount but smaller bunches with lower single berry weights in SMPH compared to VSP.