 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

Enhancing hydric stress tolerance by editing the VviMYB60 promoter with CRISPR/Cas9

Climate change presents increasing challenges to viticulture, particularly with rising water stress contributing significantly to yield losses and damages. The identification of the MYB60 transcription factor, which regulates stomatal opening and closing in Arabidopsis thaliana and Vitis vinifera, offers potential solutions. Notably, knockout studies in Arabidopsis have shown reduced stomatal opening and increased drought tolerance in myb60 mutants. Additionally, the grapevine ortholog, VviMYB60, can restore the wild-type phenotype of Arabidopsis myb60 mutants. Further investigation of the Arabidopsis promoter region has revealed that mutations in DOF motifs lead to reduced expression of AtMYB60.

Projections of vine phenology and grape composition of Tempranillo variety In Rioja DOCa (Spain) under climate change

Aims: Some of the most direct effects of climate variability on grapevines are the changes in the onset and timing of phenological events and in the length of the growing season, which may affect grape quality. The aim of this research was to analyze the projected changes in vine phenology and on grape composition of the Tempranillo variety in Rioja DOCa under different climate change scenarios.

Comparison of tannin analysis by protein precipitation and normal-phase HPLC

Tannins are a heterogenous class of polymeric phenolics found in grapes, oak barrels and wine. In red wine tannins are primarily responsible for astringency, though they also have an important role in reacting with and stabilizing pigments. There are numerous sub-classes of tannins found in wine but they all share structural heterogeneity within each sub-class, with varied polymer composition, configuration and length.

Numerous methodologies exist for the quantification of tannins, however, protein precipitation using bovine serum albumin has proved itself useful due to its strong correlation to the sensory perception of astringency and the basic instruments required for the method. Though the method can yield valuable insights into tannin composition, it cannot be automated easily and necessitates well-trained personnel.

Survey of phenological stages of disease-resistant varieties in Friuli Venezia Giulia region

Context and purpose of the study. The primary fungal diseases affecting grapevines in Europe are downy mildew and powdery mildew.

Aromatic profile of six different clones of Chardonnay grape berries in Minas Gerais (Brazil)

Aromas are one of the key points in food analysis since they are related to character, quality and consequently consumer acceptance. It is not different in the winery industry, where the aromatic profile is a combination of viticultural and oenological practices. Based on the development of more aromatic clones and on the potential to produce sparkling wines at Caldas, in the southern region of Minas Gerais (Brazil) (21°55´S and 46°23´W, altitude 1,100m), the aim of this work was the determination of volatile compounds in six different clones of Chardonnay grape berries to better understand which compounds add bouquet to the wine, and additionally comprehend the impacts of the edaphoclimatic and annual conditions on the improvement of grape-growing and winemaking practices.