OENO IVAS 2019 banner
IVES 9 IVES Conference Series 9 Simplifying the measurement of different forms of cu in wines and strategies for efficient removal

Simplifying the measurement of different forms of cu in wines and strategies for efficient removal

Abstract

Copper (Cu) is known to substantially impact wine stability through oxidative, reductive or colloidal phenomena. Recent work has shown that Cu exists predominantly in a sulfide-bound form, which may act as a potential source of sulfidic off-odours in wine and hence contribute to reductive flavours. The quanti-fication of different forms of copper in wine may allow winemakers to target more effective strategies for the removal of Cu and also to better understand the likelihood of reductive characters emerging in wines during aging.

A simple colorimetric method, utilising bicinchonic acid (BCA), was validated for the determination of the different forms of Cu in white wines, as well as the total Cu concentration in red wine. The determination of total Cu in white wines utilises an addition of excess silver(I) in order to effectively release copper from sulfide and allow quantitative complexation by BCA. The non-sulfide bound form of Cu in the white wine was determined by BCA analysis of the white wine without silver addition. In the case of red wines, a simple digestion procedure eliminated colour prior to subsequent analysis as per the white wines. The total Cu measured by the colorimetric method had an accuracy equivalent to ICPOES and a linear range of 0.04 to 1.0 mg/L. The different forms of Cu measured in white wines agreed with the results obtained by a more laborious electrochemical method.

The removal of different forms of Cu from white and red wine was subsequently studied using membrane filters of various media and pore size, depth filters and PVI/PVP. Only PVI/PVP could efficiently remove both forms of Cu, whilst the filtration techniques displayed activity for removing the sulfide bound form of Cu. Of the membrane filters, nylon and polytetrafluoroethylene media could adsorb sulfide-bound Cu, with little dependence on pore size, but their capacity for removal decreased rapidly with wine filtration volume. Similar results were observed with cellulose-based depth filters, but much greater removal efficiency was observed for cellulose depth filters impregnated with diatomaceous earth. This type of filter had active re-moval of sulfide-bound Cu from larger volumes of wine. The results allow rapid determination of the Cu forms in wine along with the assessment of the best strategies for their removal.

Abbreviations: PVI/PVP, polyvinylimidazole/polyvinylpyrrolidone.

DOI:

Publication date: June 10, 2020

Issue: OENO IVAS 2019

Type: Article

Authors

Nikolaos Kontoudakis Kieran Hirlam, Mark Smith, Paul Smith, Neil Scrimgeour, Paul Bowyer, Eric Wilkes, Andrew Clark

Andrew Clark: Charles Sturt University-National Wine and Grape Industry Centre Eric Wilkes, Neil Scrimgeour, Kieran Hirlam, Mark Smith: The Australian Wine Research Institute Mark Smith: Wine Australia Paul Bowyer: Blue H2O Filtration

Contact the author

Keywords

Copper measurment , Sulfide-bound Cu, Filtration , PVP/PVI 

Tags

IVES Conference Series | OENO IVAS 2019

Citation

Related articles…

Significance of factors making Riesling an iconic grape variety

Riesling is the iconic grape variety of Germany and accounts for 23% of the German viticulture acreage, which comprises 45% of the worldwide Riesling plantings. Riesling wines offer a wide array of styles from crisp sparkling wines to highly concentrated and sweet Trockenbeerenauslese or Icewines. However, its thin berry skin makes Riesling more vulnerable to detrimental environmental threats than other white wine varieties.  

Malolactic fermentation in wine production

What influence do these bacteria have on wines? What new bacteria are being studied to carry out this fermentation? Find below articles about malolactic fermentation published in our 3 media (OENO One, IVES Technical Reviews and IVES Conference Series). OENO One...

Metabolomics screening of Vitis sp. interspecific hybrids to select natural ingredients with cosmetic purposes

Introducing natural ingredients using green chemistry practices is a major challenge in cosmetics industry to follow the market trend. Among the plants of cosmetic interest, vine products show a remarkable diversity of natural substances with high potential for the cosmetic and dermatological sectors. To date, research focuses on well-known compounds like E-resveratrol and E-ε-viniferin,

WAC 2022: Abstracts are available on IVES Conference Series

In order to disseminate the scientific results presented during the WAC 2022 , the organizers have decided to share the abstracts of the oral communications and posters with Open Access on IVES Conference Series. The fifth edition of the International Conference...

Winemaking techniques and wine tasting methods at the end of the Middle Ages

Les pratiques de vinification et de dégustation du vin sont souvent perçues, à travers un discours marketing très puissant, sous l’angle d’une tradition millénaire qui perdure depuis le Moyen Âge. En Bourgogne, il est courant de rattacher les racines de ces pratiques à l’activité des institutions ecclésiastiques qui possédaient d