Macrowine 2021
IVES 9 IVES Conference Series 9 Fluorescence spectroscopy with xgboost discriminant analysis for intraregional wine authentication

Fluorescence spectroscopy with xgboost discriminant analysis for intraregional wine authentication

Abstract

AIM: This study aimed to use simultaneous measurements of absorbance, transmittance, and fluorescence excitation-emission matrix (A-TEEM) combined with chemometrics as a rapid method to authenticate wines from three vintages within a single geographical indication (GI) according to their subregional variations.

METHODS: The A-TEEM technique (Gilmore, Akaji, & Csatorday, 2017) has been applied to analyse experimental Shiraz wines (n = 186) from six subregions of Barossa Valley, South Australia, from 2018, 2019 and 2020 vintages. Absorbance spectra and EEM fingerprints of the wines were recorded and the data were fused for multivariate statistical modelling with extreme gradient boost discriminant analysis (XGBDA) as reported by Ranaweera, Gilmore, Capone, Bastian, and Jeffery (2021) to classify wine according to their subregions. The cross-validated (k =10, Venetian blinds) confusion matrix score probabilities of classes were used to assess the accuracy of the classification models. A similar procedure was also carried out to discriminate subregions for a single vintage year. Basic chemical parameters (alcohol %v/v, pH, titratable acidity, and volatile acidity) were modelled with the partial least squares regression (PLSR) using A-TEEM data and reference chemical data.

RESULTS: Results have shown an unprecedented 100% correct classification of wines according to subregion across the three vintages and 98% accuracy for subregion in a single vintage year. Other model performance parameters of confusion matrix, including sensitivity, specificity, precision, and F1 score, were also showing the highest values (1.0) for each of the subregions. PLSR modelling revealed that A-TEEM data can also be used for a rapid assessment of basic wine chemical parameters. Notably, the results confirmed a distinct resolution among subregions despite their relatively close proximity within a single GI, indicating the effect of terroir on intraregional variation.

CONCLUSIONS

The sensitivity of A-TEEM allied with multivariate statistical analysis of fluorescence data facilitated the accurate classification of Shiraz wines according to the subregion of origin and production year. As a robust analytical method, A-TEEM can help identify the drivers of regional expression of wine and can potentially be developed for use within the supply chain to guarantee the provenance indicated on the label and to provide an assurance of quality. Overall, A-TEEM with XGBDA modelling continues to be shown as an accurate wine authentication tool that could even be applied at a subregional level.

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Ruchira Ranaweera

Department of Wine Science, The University of Adelaide, South Australia, Australia,Adam GILMORE, Horiba Instruments Inc., Piscataway, New Jersey, USA Dimitra CAPONE, The Australian Research Council Training Centre for Innovative Wine Production, The University of Adelaide Susan BASTIAN, The Australian Research Council Training Centre for Innovative Wine Production, The University of Adelaide David JEFFERY, The Australian Research Council Training Centre for Innovative Wine Production, The University of Adelaide

Contact the author

Keywords

geographical indication, authenticity, subregion, excitation-emission matrix, chemometrics, terroir

Citation

Related articles…

Co-design and evaluation of spatially explicit strategies of adaptation to climate change in a Mediterranean watershed

Climate change challenges differently wine growing systems, depending on their biophysical, sociological and economic features. Therefore, there is a need to locally design and evaluate adaptation strategies combining several technical options, and considering the local opportunities and constraints (e.g. water access, wine typicity). The case study took place in a typical and heterogeneous Mediterranean vineyard of 1,500 ha in the South of France. We developed a participatory modeling approach to (1) conceptualize local climate change issues and design spatially explicit adaptation strategies with stakeholders, (2) numerically evaluate their effects on phenology, yield and irrigation needs under the high-emissions climate change scenario RCP 8.5, and (3) collectively discuss simulation results. We organized five sets of workshops, with in-between modeling phases. A process-based model was developed that allowed to evaluate the effects of six technical options (late varieties, irrigation, water saving by reducing canopy size, adjusting cover cropping, reducing density, and shading) with various distributions in the watershed, as well as vineyard relocation. Overall, we co-designed three adaptation strategies. Delay harvest strategy with late varieties showed little effects on decreasing air temperature during ripening. Water constraint limitation strategy would compensate for production losses if disruptive adaptations (e.g. reduced density) were adopted, and more land got access to irrigation. Relocation strategy would foster high premium wine production in the constrained mountainous areas where grapevine is less impacted by climate change. This research shows that a spatial distribution of technical changes gives room for adaptation to climate change, and that the collaboration with local stakeholders is a key to the identification of relevant adaptation. Further research should explore the potential of adaptation strategies based on soil quality improvement and on water stress tolerant varieties.

Climate, Viticulture, and Wine … my how things have changed!

The planet is warmer than at any time in our recorded past and increasing greenhouse emissions and persistence in the climate system means that continued warming is highly likely. Climate change has already altered the basic framework of growing grapes for wine production worldwide and will likely continue to do so for years to come. The wine sector can continue to play an important role in leading the agricultural sector in addressing climate change. From developing on…

Short-term relationships between climate and grapevine trunk diseases in southern French vineyards

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

Towards adaptation to climate change in Rioja: Quality evaluation of wines obtained from Grenache x Tempranillo selections

The wine sector is of great relevance and tradition in Mediterranean countries, however, it may be most susceptible to climate change. In recent years, wine production is facing changes worldwide, both at environmental as well as commercial levels, due to global warming and the shift in consumers’ preferences. Wine growers and wine makers are in search of solutions that allow to face these new challenges. One of the most promising initiatives in the long term is the introduction of new plant materials, specifically intraspecific hybridizations between premium varieties that may improve traditional germplasm in its adaptation to climate change. These inter-varietal crosses have the potential to generate quality wines, whilst maintaining the regional typicity, and constitute an attractive alternative for the consumer due to their sensory attributes. In this study, we have evaluated wines from 29 intraspecific Garnacha x Tempranillo hybrids in two different locations, with the aim to assess their oenological potential and sensory attributes. Thirteen of the selections were white and 16 were red. Microvinifications were conducted with two or three replications depending on grape availability. Conventional oenological parameters were determined for all wines. The sensory evaluation and hedonic scores were given by five experts. Red selections obtained higher quality scores than white ones. Among the white selections with higher quality scores, GT-41 Varea and GT-159 Varea outstand, due to their high total acidity and high malic acid content. Regarding red selections, GT-57 Varea and GT-57 UR were perceived as higher in quality, highlighted for their moderate alcoholic and high anthocyanin content. Our results indicate that intraspecific hybridization may be a powerful tool for adapting traditional cultivars to climate change in Rioja.

20-Year-Old data set: scion x rootstock x climate, relationships. Effects on phenology and sugar dynamics

Global warming is one of the biggest environmental, social, and economic threats. In the Douro Valley, change to the climate are expected in the coming years, namely an increase in average temperature and a decrease in annual precipitation. Since vine cultivation is extremely vulnerable and influenced by the climate, these changes are likely to have negative effects on the production and quality of wine.
Adaptation is a major challenge facing the viticulture sector where the choice of plant material plays an important role, particularly the rootstock as it is a driver for adaptation with a wide range of effects, the most important being phylloxera, nematode and salt, tolerance to drought and a complex set of interactions in the grafted plant.
In an experimental vineyard, established in the Douro Region in 1997, with four randomized blocs, with five varieties, Touriga Nacional, Tinta Barroca, Touriga Franca and Tinta Roriz, grafted in four rootstocks, Rupestris du Lot, R110, 196-17C, R99 and 1103P, data was collected consecutively over 20 years (2001-2020). Phenological observations were made two to three times a week, following established criteria, to determine the average dates of budbreak, flowering and veraison. During maturation, weekly berry samples were taken to study the dynamics of sugar accumulation, amongst other parameters. Climate data was collected from a weather station located near the vineyard parcel, with data classified through several climatic indices.
The results achieved show a very low coefficient of variations in the average date of the phenophases and an important contribution from the rootstock in the dynamic of the phenology, allowing a delay in the cycle of up to10-12 days for the different combinations. The Principal Component Analysis performed, evaluating trends in the physical-chemical parameters, highlighted the effect of the climate and rootstock on fruit quality by grape varieties.