 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Chemical diversity of 'special' wine styles: fortified wines, passito style, botrytized and ice wines, orange wines, sparkling wines 9 Macromolecular characterization of disease resistant red wine varieties (PIWI)

Macromolecular characterization of disease resistant red wine varieties (PIWI)

Abstract

AIM: Pilzwiderstandsfähige (PIWI) are disease resistant Vitis vinifera interspecific hybrid varieties that are receiving increasing attention for ability to ripen in cool climates and their resistance to grapevine fungal diseases. Wines produced from these varieties have not been characterized, especially regarding their macromolecular composition. This study characterised and quantified colloid-forming molecules (proteins, polysaccharides and phenolics) of red PIWI wines produced in the UK.

METHODS: In 2019 6 wines were made from the PIWI varieties Rondo, Cabernet Jura, Cabernet Cortis, Cabernet Noir, Regent and Cabertin grown at the Plumpton Rock Lodge Vineyard in Sussex (UK) and harvested at similar level of maturity (TSS, pH and TA). All juice was chaptalized to the same potential alcohol of 12%. Small scale winemaking (1L) was performed in quadruplicate using Bodum® coffee plungers to manage maceration [1]. Residual sugar content, pH, and titratable acidity were monitored during fermentation. For finished wines, the protein and polysaccharide content was measured by HPLC-SEC [2], while the total phenolic content was assessed using the Folin-Ciocalteau method [3]. The protein profile of the wines was further investigated by SDS-PAGE [4].

RESULTS: Fermentations (n=24) were all carried out to completion within 8 days. The resulting wines showed important differences in terms of their macromolecular composition. The total polysaccharide content ranged between 903-1217 mg/L and was higher than the typical content of red wines [5]. Also, the total phenolic content was greater than typical red wines from Vitis vinifera (range 2478-4678 mg/L), while the total protein concentration ranged between 114 -152 mg/L. Typical values for red wine range from 10-200 mg/L [4,6]. The electrophoresis analysis showed the presence of pathogenesis-related (defence) proteins, namely chitinases and thaumatin-like proteins in all wines, while a lipid transfer protein (LTP) was found in all wines except for Cabernet Cortis. This is noteworthy as LTPs can cause severe allergenic reactions [7].

CONCLUSIONS:

Hybrid red grape varieties have the potential to produce wines with chemical and macromolecular composition in line with those from Vitis vinifera. This is a promising result for their future adoption in winegrowing regions subjected to difficult climatic conditions and high disease pressure. However, given that PIWI varieties are likely to over-produce pathogenesis-related proteins as a defence mechanism, future investigations should explore the role of these proteins with regard to colloidal and colour stability and allergenic potential.

DOI:

Publication date: September 16, 2021

Issue: Macrowine 2021

Type: Article

Authors

Edward Brearley

Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, Italy,Matteo MARANGON, Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, Italy Daniel JACKSON, Plumpton College, England Tony MILANOWSKI, Rathfinny Wine Estate, England Gregory DUNN, Plumpton College, England

Contact the author

Keywords

disease resistant, piwi, red wines, proteins, polysaccharides, phenolics, colloids

Citation

Influence of protective colloids on tartrate stability, polysaccharide contents and volatile compound profile of a white wine

The tartaric salts precipitation is one of the main issues regarding wine instability 1. In addition to the well-known and deeply studied phenomena of potassium hydrogentartrate precipitation (KHT), the last decade has been increased the phenomena of calcium tartrate (CaT) precipitation, that is a concern for the wine industry 2.

Pruned vine biomass exclusion from a clay loam vineyard soil – examining the impact on physical/chemical properties

The wine industry worldwide faces increasing challenges to achieve sustainable levels of carbon emission mitigation. This project seeks to establish the feasibility of harvesting winter pruned vineyard biomass (PVB) for potential use in carbon footprint reduction, through its use as a renewable biofuel for energy production. In order to make this recommendation, technical issues such as the potential environmental impact, chemical composition and fuel suitability, and logistical challenges of harvesting biomass needs to be understood to compare with the results from similar studies. Of particular interest is the role PVB plays as a carbon source in vineyard soils and what effect annual removal might have on soil carbon sequestration. A preliminary trial was established in the Waite Campus vineyard (University of Adelaide) to test current management strategies. Vines are grown in a Eutrophic, Red Dermosol clay loam soil with well managed midrow swards. A comparison was undertaken of mid-row treatments in two 0.25 Ha blocks (Shiraz and Semillon), including annual cultivation for seed bed preparation, the deliberate exclusion of PVB (25 years) and incorporation of PVB (13 years) at an average of 3.4 and 5.5 Mg/Ha-1 for Shiraz and Semillon respectively. In both 0-10cm and 10-30cm soil core sample depths, combined soil carbon % measures in the desired range of 1.80 to 3.50, were not significantly different between treatments or cultivars and yielded an estimated 42 Mg/ha-1 of sequestered soil carbon. Other key physical and chemical measures were likewise not significantly different between treatments. Preliminary results suggest that in a temperate zone vineyard, managed such as the one used in this study, there is no long term negative impact on soil carbon sequestration through removing PVB. This implies that growers could confidently harvest PVB for use in several end fates including as a bio fuel.

Study of the grape glycosidic aroma precursors by crossing SPE-GC/MS, SPME-GC/MS and LC/QTOF methods

Depending on the variety, grapes contain several chemical classes of aromatic compounds (i.e., terpenols, norisoprenoids, benzenoids) mainly stored as glycosides in berry skin.

Tracking innovations for glyphosate-free in sloppy or terraced vineyard

Context and purpose of the study. Reducing pesticide use such as glyphosate, is a key challenge to support sustainability of viticulture systems and resilience of vineyard.

ASSESSMENT OF ‘DOLCETTO’ GRAPES AND WINES FROM DIFFERENT AREAS OF OVADA DOCG

Dolcetto (Vitis vinifera L.) is one of the traditionally cultivated varieties in Piedmont (north-east Italy). Dolcetto wines have long been associated with local consumption and they are little known internationally. In particular, the Ovada area (south-east Piedmont), even if it represents a small share of the regional PDO Dolcetto production, is one of the oldest and vocated territory, giving wine also suitable for aging. In this study, the basic composition and phenolic content of Dolcetto grapes for Ovada DOCG wines have been investigated in three different vintages (2020-2022), as well as the main aspects of the derived commercial and experimental wines (basic parameters, phenolics, volatile compounds, sensory properties).