Terroir 2020 banner
IVES 9 IVES Conference Series 9 Unravelling regional typicality of Australian premium Shiraz through an untargeted metabolomics approach

Unravelling regional typicality of Australian premium Shiraz through an untargeted metabolomics approach

Abstract

Aims: The current study seeks to demonstrate that premium Shiraz wines from different Australian geographic indications (GI) can be distinguished by their volatile compound composition. 

Method and Results: Barossa, McLaren Vale, Hunter Valley, Canberra District, Heathcote and Yarra Valley were selected to represent a range of climatic conditions. In each region, three to four wines were chosen by a panel of local winemakers to represent the regional wine styles. Volatile fractions of all wines (n = 22) were extracted from 3 bottles, using a solid phase extraction protocol. The extracts were analysed in random order with GC-EI-QTOFMS. Features (a feature is an ion fragment with unique m/z, retention time and intensity) were extracted from the raw MS data and then grouped and deconvoluted, to give 321 ‘compound’ spectra. The feature with the highest intensity in each spectrum was taken to build a classification model using the random forests (RF) algorithm. This model was able to correctly classify all samples according to their GI. Features with lower contributions to the model were gradually eliminated, and 80 features were found to be sufficient to maintain the accuracy of classification. Of these 80 features, 45 were tentatively identified by comparing their mass spectra and Kovats retention indices with either an in-house library or the NIST 14 library. A range of these compounds, including terpenoids, benzenoids, esters, furan derivatives and aliphatic alcohols, have been associated with grape composition, wine making influences and the aging process.

Conclusion:

This study showed that Shiraz wines from different GIs have unique volatile ‘fingerprints’. These classifications may be associated with the unique terroir of the GI, which includes climatic and production differences. Well-designed processing tools for MS data and robust data mining algorithms served as a powerful combination of techniques to uncover the regional ‘fingerprints’.

Significance and Impact of the Study: This study realised the challenging assignment of separating commercial Shiraz wines from six GIs according to their volatile composition. Forming a part of a broader project that include sensory and climate data, it helps to benchmark regional styles of Australian Shiraz wine.  

Download the PDF

DOI:

Publication date: March 17, 2021

Issue: Terroir 2020

Type: Video

Authors

Sijing Li1*, Leigh Schmidtke1, Wes Pearson1,2, Leigh Francis2, John Blackman1

1National Wine and Grape Industry Centre, Charles Sturt University, School of Agricultural and Wine Science, Locked Bag 588, Wagga Wagga, NSW 2678, Australia
2The Australian Wine Research Institute, PO Box 197, Glen Osmond, SA 5064, Australia

Contact the author

Keywords

Terroir, metabolomics, Australia, Shiraz, climate

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

How are canned wine drinkers perceived? An investigation involving Swiss nationals and different scenarios of outdoor leisure activities

This study examines how people who consume wine in cans are perceived in terms of their basic personality characteristics, helps understand the role of cultural background on people’s perception, and verify the role played by the consumption context on the perception. Our hypothesis is that prejudice and negative attitudes towards wine in cans might exert a negative effect on the evaluation of people who consume canned wine. To evaluate this hypothesis, the consumption of wine in cans was evoked in four different contexts of use during outdoor leisure activity (beach resort, ski resort, desert safari, and party). In order to examine the effect of culture on subject’s response we use participants from Switzerland, a country where three different cultures, associated with three different languages, cohabit.

Read More

Soil incorporation of new superabsorbent hydrogels to improve vine tolerance to summer stress: physiological validation and vineyard applications

Hydrogels are soil-conditioning materials capable of absorbing substantial amounts of water relative to their weight.

Read More

Impact of the ‘Pinot’-family on early ripening in cool climate viticulture varieties

‘Pinot Precoce Noir’ (PPN) is an early ripening clone of ‘Pinot Noir’ (PN). The phenological differentiation is visible by an about two weeks earlier onset of veraison. It was found that the early veraison locus Ver1 on chromosome 16, previously identified in ‘Calardis Musqué’, originated from PPN. A highly correlated SSR marker, namely GF16-Ver1, was developed and tested for its ability to molecularly differentiate between PPN and PN as well as its potential to trace individual descendants.

Read More

L’effet du climat viticole sur la typicité des vins rouges: caractérisation au niveau des régions viticoles Ibéro-Américaines

Il n’existe presque pas d’études qui caractérisent l’effet du climat viticole sur la typicité des vins en considérant les différents types de climats à l’échelle mondiale. Cette étude fait partie d’un projet CYTED de zonage vitivinicole. L’objectif a été de caractériser l’effet du climat viticole sur la typicité des vins sur une macro région viticole du monde.

Read More

Methoxypyrazine concentrations in grape-bunch rachis are influenced by rootstock, region, light, and scion.

Methoxypyrazines (MPs) are readily extracted from grape berry and rachis during fermentation and can impart “green” and “herbaceous” sensory attributes to wine. Irrespective of whether MPs, including 3-isobutyl-2-methoxypyrazine (IBMP), 3-isopropyl-2-methoxypyrazine (IPMP), and 3-sec-butyl-2-methoxypyrazine (SBMP), are extracted from berry or other vine material, techniques for remediation of wine with overpowering sensory characters attributable to MPs suffer from poor specificity or produce undesirable sensory outcomes, meaning that alternative control approaches are needed.

Read More