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.  

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…

Phenological characterization of a wide range of Vitis Vinifera varieties

In order to study the impact of climate change on Bordeaux grape varieties and to assess the adaptation capacities of candidates to the grape varieties of this wine region to the new climatic conditions, an experimental block design composed of 52 grape varieties was set up in 2009 at the INRAE Bordeaux Aquitaine center. Among the many parameters studied, the three main phenological stages of the vine (budburst, flowering and veraison) have been closely monitored since 2012. Observations for each year, stage and variety were carried out on four independent replicates. Precocity indices have been calculated from the data obtained over the 2012-2021 period (Barbeau et al. 1998). This work allowed to group the phenological behaviour of the grapevine varieties, not only based on the timing of the subsequent developmental stages, but also on the overall precocity of the cycle and the total length of the cycle between budburst and veraison. Results regarding the variability observed among the different grape varieties for these phenological stages are presented as heat maps.

Impact of geographical location on the phenolic profile of minority varieties grown in Spain. II: red grapevines

Because terroir and cultivar are drivers of wine quality, is essential to investigate theirs effects on polyphenolic profile before promoting the implantation of a red minority variety in a specific area. This work, included in MINORVIN project, focuses in the polyphenolic profile of 7 red grapevines minority varieties of Vitis vinifera L. (Morate, Sanguina, Santafe, Terriza Tinta Jeromo Tortozona Tinta) and Tempranillo) from six typical viticulture Spanish areas: Aragón (A1), Cataluña (A2), Castilla la Mancha (A3), Castilla –León (A4), Madrid (A5) and Navarra (A6) of 2020 season. Polyphenolic substances were extracted from grapes. 35 compounds were identified and quantified (mg subtance/kg fresh berry) by HPLC and grouped in anthocyanins (ANT) flavanols (FLAVA), flavonols (FLAVO), hydroxycinnamic (AH), benzoic (BA) acids and stilbenes (ST). Antioxidant activity (AA, mmol TE /g fresh berry) was determined by DPPH method. The results were submitted to a two-way ANOVA to investigate the influence of variety, area and their interaction for each polyphenolic family and cluster analysis was used to construct hierarchical dendrograms, searching the natural groupings among the samples. Sanguina (A3) had the most of total polyphenols while Tempranillo (A5) those of ANT. Sanguina (A2) and (A3) reached the highest values of FLAVO, FLAVA and AA. These two last samples had also the maximum of AA. The effect cultivar and area were significant for all polyphenolic families analyzed. A high variability due to variety (>50%) was observed in FLAVA and the maximum value of variability due to growing area was detected in AA (86.41%), ANT and FLAVO (51%); the interaction variety*zone was significant only for ANT, FLAVO, EST and AA. Finally, dendrograms presented five cluster: i) Sanguina (A2); ii) Sanguina (A3); iii) Tempranillo (A5); iv) Tempranillo (A3); Terriza (A3,A5), Morate (A5,A6); v) Santafé (A1,A6); Tortozona tinta (A1,A3,A6); Tinta Jeromo (A3,A4).

Legacy of land-cover changes on soil erosion and microbiology in Burgundian vineyards

Soils in vineyards are recognized as complex agrosystems whose characteristics reflect complex interactions between natural factors (lithology, climate, slope, biodiversity) and human activities. To date, most of the unknown lies in an incomplete understanding of soil ecosystems, and specifically in the microbial biodiversity even though soil microbiota is involved in many key functions, such as nutrient cycling and carbon sequestration. Soil biological properties are indicative of soil quality. Therefore, understanding how soil communities are related to soil ecosystem functioning is becoming an essential issue for soil strategy conservation. Here, we propose to assess the importance of land-cover history on the present-day microbiological and physico-chemical properties. The studied area was selected in the Burgundian vineyards (Pernand-Vergelesses, Burgundy, France) where land occupation has been reconstructed over the last 40 years. Soil samples were collected in five areas reflecting various land cover history (forest, vineyards, shifting from forest to vineyards). For each area, physico-chemical parameters (pH, C, N, P, grain size) were measured and DNA was extracted to characterize the abundance and diversity of microbial communities. The obtained results show significant differences in the five areas suggesting that present-day microbial molecular biomass and bacterial taxonomic is partly inherited from past land occupation. Over longer period of time, such study of land-uses legacies may help to better assess ecosystem recovery and the impact of management practices for a better soil quality and vineyards sustainability.

Different soil types and relief influence the quality of Merlot grapes in a relatively small area in the Vipava Valley (Slovenia) in relation to the vine water status

Besides location and microclimatic conditions, soil plays an important role in the quality of grapes and wine. Soil properties influence…

Soil quality in Beaujolais vineyard. Importance of pedology and cultural practices

A pedological study was carried out from 2009 to 2017 in Beaujolais vineyard, to improve physical and chemical knowledge of soils. It was completed in 2016 and 2017 by the current study, dealing with microbial aspects, in order to build a reference frame for improved advice in soil management. Microbial biomass was measured on representative plots of the six most common soil types identified in Beaujolais and, for each soil type, on plots with different levels of the main impacting parameters: total organic carbon, pH, cation exchange capacity, extractable copper. A total of 59 soil samples were collected. Confirming the results of various trials carried out in Beaujolais over the past 20 years, the results of the present study showed that the soils were still alive, but exhibited a large variability of biological parameters, which appeared dependant on both pedological and anthropic factors. Therefore, a good interpretation of biological parameters and advice for vine growers must rely on a pedologically-based referential with differentiated main driving factors. For example, the control of pH is of primary importance in granitic soils and in no way organic matter addition can improve soil quality if pH is too low. Conversely, in calcareous soils, biological parameters are more directly affected by direct or indirect (cover crops for example) inputs of organic matter. The use of biological parameters, such as microbial biomass, is of great potential value to improve advice on agro-viticultural practices (soil management, fertilization, liming, etc.), basis of a sustainable wine production on fragile soils.