IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 The interaction between wine polyphenolic classes and poly-L-proline is impacted by oxygen

The interaction between wine polyphenolic classes and poly-L-proline is impacted by oxygen

Abstract

Oxygen plays a key role in the evolution of wine chemistry, within the non-volatile matrix. Polyphenol composition and structure, as well as the process of tannin polymerisation are directly impacted by oxidation, and this can occur during both fermentation and ageing. Polyphenols play an important role in red wine and exhibit a wide diversity in their structure and properties. They are responsible for wine colour, texture and taste (astringency, bitterness) and exhibit some health properties. The principal class of non-flavonoid polyphenolic compounds are the phenolic acids and stilbenes. Among the flavonoids, anthocyanins and tannins are the major structural classes. The aim of this study was to characterise the detailed response of wine polyphenolic structure and composition to an oxygen treatment applied during fermentation. A specific focus was to determine the interaction of discrete polyphenolic classes with poly-L-proline (PLP). A control Shiraz wine was prepared under reductive conditions during fermentation, in triplicate. To the same grape source, an aeration treatment was initiated on day 3 following a 1.8 °Bé decrease for 48 h at 5 L/min, also in triplicate.  After a 12-month ageing period, wines were fractionated where: F1 = Phenolic acids, F2 = flavan-3-ol monomers, F3 = flavan-3-ol oligomers, F4 = anthocyanins, pyranoanthocyanins; and F5 = polymeric proanthocyanidins, pigmented proanthocyanins and other derived complexes. The composition of fractions F1 to F4 was verified by LC-MS, and F5 was characterised by a combination of analytical techniques specific to proanthocyanidins. The interaction between the polyphenol fractions and PLP was measured by isothermal titration calorimetry (ITC). A strong binding interaction was observed between F1, the phenolic acids, and PLP by ITC, and was not affected by the oxygen treatment. In fact, a strong hydrophobic interaction and hydrogen bonding was implicated in the interaction. It was found that for fractions F2 and F3, no binding events with PLP were observed by ITC, irrespective of the oxygen level applied. Stronger binding events with PLP were observed for the F4 and F5 polyphenolic fractions, but interestingly, only in those prepared from wines which had oxygen treatment. Moreover, hydrophobic interaction and hydrogen bonding was detected just for the oxygen treatment for F4 and F5. Contrary to expectation, no binding with PLP could be detected for F4 and F5 from the control wine. Further investigation of the properties of the fractions was conducted to account for the differences observed, including their composition, hydrophobicity and aggregation. This presentation will provide new insights into the potential role of discrete polyphenolic classes in driving in-mouth sensory properties, like astringency, which might be elicited following binding with proline-rich salivary proteins.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Jouin Alicia1, Falconer Robert J.2, Waterlot Aude3, Day Martin1, Schmidt Simon1 and Bindon Keren1

1The Australian Wine Research Institute, PO Box 197, Glen Osmond, South Australia, 5064, Australia 
2Department of Chemical Engineering and Advanced Materials, University of Adelaide, Adelaide, SA, 5005, Australia
3Department of Food Science and Human Nutrition, Courtesy Faculty, Horticulture, Iowa State University, 2567 Food Sciences Building, 536 Farm House Lane, Ames, IA 50011, USA

Contact the author

Keywords

Tannins, Anthocyanins, Oxygen, Isothermal Titration Calorimetry, Astringency

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

Effect of SO2, GSH and gallotannins on the shelf-life of a cortese white wine

Studying the effect of the addition of reduced glutathione (GSH) and/or gallotannins at bottling to limit the use of SO2 in white winemaking.

Application of an in vitro digestion model to study the bioaccessibility and the effect of the intestinal microbiota on the red wine proanthocyanidins 

Proanthocyanidins are important phenolic fraction for wine quality, contributing to astringency, bitterness and color. Their metabolism begins in the mouth and continues throughout the gastrointestinal tract; however, most of them are accumulated in the colon where are metabolized by the intestinal microbiota, giving rise to a whole series of phenolic acids that may have greater activity at physiological level than the precursors[1]. This study aimed to evaluate in vitro the bioaccessibility of proanthocyanidins in a red wine developed by Bodegas Pradorey, as well as to evaluate the potential effect of intestinal microbiota on polyphenols metabolism identifying and quantifying secondary metabolites.

Exploring the inner secrets of grapevine: a journey through plant-microbe interactions

Throughout centuries of anthropocentric breeding, plants have been selectively bred to enhance their quality traits and yield, often overlooking the importance of neglected attributes, like those involved in the interactions with beneficial microorganisms. This phenomenon led to an alteration in the distribution of photosynthetic products, shifting from defence mechanisms to growth, commonly described as ‘domestication syndrome’. Addressing the losses stemming from this condition is imperative just as unravelling the concealed communication between grapevines and beneficial microorganisms.

Impact of aging on dimethyl sulfide (DMS) in Corvina and Corvinone wines

Dimethyl sulfide (DMS) is a low molecular weight sulfur compound produced in wine during aging by the chemical degradation of S-Methyl-L-methionine (SMM). Investigating the aromatic profile of Amarone commercial wines from different wineries, it was found that DMS presented a high variation in concentration across wine samples ranging from 2.88 to 64.34 μg/L, which potentially can