GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 The impacts of frozen material-other-than-grapes (MOG) on aroma compounds of red wine varieties

The impacts of frozen material-other-than-grapes (MOG) on aroma compounds of red wine varieties

Abstract

Context and purpose of the study – An undesirable note called “floral taint” has been observed in red wines by winemakers in the Niagara region caused by large volumes of frozen leaves and petioles [materials-other-than-grapes (MOG)] introduced during mechanical harvest and subsequent winemaking late in the season. The volatiles, which we hypothesized are responsible, are primarily terpenes, norisoprenoids, and specific esters in frozen leaves and petioles. The purpose of this study was to investigate the volatile compounds which may cause the floral taint problem and explore how much of them (thresholds) may lead to the problem. Also, the glycosidic precursors of some of these compounds were analyzed to see the changes happening during frost events.
Materials and methods – Research winemaking was conducted in 2016, 2017 and 2018. All fermentations were based on 40-kg replicated ferments of Cabernet Franc (CF) and Cabernet Sauvignon (CS). MOG Treatments were (by weight): 0, 0.5%, 1%, 2% and 5% petioles, and 0, 0.25%, 0.5%, 1%, and 2% leaf blades. In 2017 and 2018, different yeast strains and harvest strategies were also included in the CF treatments. Yeast treatments included CSM, EC1118 and FX10. Harvest strategies involved conventional machine harvesting (MH), Braud-New Holland Opti MH, Gregoire 8 MH, MH + optical sorting, and MH with pre-harvest leaf removal. Concentrations of key odor-active compounds were quantified by gas chromatography-mass spectrometry with stir bar sorptive extraction.
Results – Several compounds including cis- and trans-rose oxides, β-ionone, citronellol, linalool, eugenol, methyl and ethyl salicylate were higher in MOG treatments for both CF and CS and their concentrations increased linearly with the accumulative levels of petioles or leaves. Principal components analysis showed petiole and leaf treatments were separated apart from the control sample with the 5% petioles and 2% leaves as the extremes. Petiole and leaf treatments were spread out on different axes, which indicated their large differences in volatile compositions. Interestingly, eugenol and rose oxides and many other compounds followed linear curves with the addition of petioles and leaves in the 2016 vintage, which could be potentially used as a tool to communicate with winemakers on potential floral taint risk based on their sensory thresholds. Preliminary results from 2017 showed that more terpene compounds were found in the standard MH treatment than the hand-harvested control, and the yeast EC1118 produced the least terpenes out of three different yeasts among all leaf and petiole addition treatments in most cases, while yeast strain FX10 produced the highest terpene concentrations. In general, petiole additions contributed more to the floral taint problem than leaf additions. Specifically, petioles contributed terpenes and salicylates (floral notes) to the wines, and leaves contributed norisoprenoids and C6 alcohols (green notes).

DOI:

Publication date: March 12, 2024

Issue: GiESCO 2019

Type: Poster

Authors

Jiaming WANG1, Emilie AUBIE2, Yi-Bin LAN1, Marnie CROMBLEHOLME1, Andrew REYNOLDS1*

1 Cool Climate Oenology & Viticulture Institute, Brock University, St. Catharines, ON, L2S 3A1, Canada. 2Andrew Peller Winery, 697 S Service Rd, Grimsby, ON L3M 4E8, Canada

Contact the author

Keywords

MOG, floral taint, yeasts, harvest strategies, leaves, petioles, GC-MS, terpenes

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Stem growth disorder and xylem anatomy modifications during esca pathogenesis in grapevines

Esca is a grapevine vascular disease with detrimental consequences on vineyard yield and longevity. Recently, esca leaf symptom development has been shown to result in the occlusion of xylem vessels by tyloses in leaves and stems, leading to hydraulic failure. However, little is known regarding the response of xylem anatomy and stem growth to esca in different varieties . Here we studied the impact of esca leaf symptom development on grapevine physiology, stem growth, and xylem anatomy in two widespread cultivars, Cabernet sauvignon and Sauvignon blanc.

Preserving wine typicity in a climate change scenario: Examples from the Willamette Valley, Oregon

Aims: Wine typicity is defined as a reflection of varietal origins, cultures and traditions of the wine. These aspects are many times also extremely important when considering a wines quality. However, as climate change occurs the typicity of wines may also change. With the long history of winemaking it is possible to define a wines typicity and how it has changed as climate alters. 

Integrated multiblock data analysis for improved understanding of grape maturity and vineyard site contributions to wine composition and sensory domains

Much research has sought to define the complex contribution of terroir (varieties x site x cultural practices) on wine composition. This investigation applied recent advances in chemometrics to determine relative contributions of vine growth, berry maturity and site mesoclimate to wine composition and sensory profiles of Shiraz and Cabernet Sauvignon for two vintages.

Prefermentative CO2 saturation of grape must to obtaining white wines with low SO2 content

The objective this work has been study the possibility of partially or completely replacing sulphur in the winemaking of white wines through the use of the prefermentative saturation of musts with CO2.

Intelligent use of ethanol for the direct quantitative determination of volatile compounds in spirit drinks

The quality of any alcoholic beverage depends on many parameters, such as cultivars, harvesting time, fermentation, distillation technology used, quality and type of wooden barrels (in case of matured drinks), etc.; however, the most important factor in their classification is content of volatile compounds.