IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Hyperspectral imaging and Raman spectroscopy, nondestructive methods to assess wine grape composition

Hyperspectral imaging and Raman spectroscopy, nondestructive methods to assess wine grape composition

Abstract

Grape composition is of high interest for producing quality wines. For that, grape analyses are necessary, and they still require sample preparation, whether with classical analyses or with NIR analyses. The aim of the study was to test the ability of two nondestructive analyses, directly on grapes, hyperspectral imaging (HSI) and Raman spectroscopy to assess their composition.
For that, 7 grape varieties were analyzed for 2 vintages. Each grape was characterized by its technological ripening (levels of sugars, organic acids and pH) and its phenolic ripeness (total phenolic, total flavonoids, total anthocyanins contents, as well as extractable phenolic, extractable flavonoids, extractable anthocyanins, values obtained from a model wine maceration from skins, and color intensity). Spectra were recorded on 100 and 40 fresh berries per date and variety respectively with hyperspectral imaging and Raman. Raw data underwent different pretreatments (SNV, 1st and 2nd derivative) and PLS-R were then realized in order to provide models to assess grape composition.
The results showed that the 1st derivative data pretreatment generated better models and was then kept for all following analyses. Both methods, Raman spectroscopy and hyperspectral imaging, showed good ability to assess technological ripening parameters (sugar and acid contents) as well as phenolic content (TPI, Total Phenolics, Total Anthocyanins, Total Flavonoids and their extractable equivalents) (with globally R² > 0.81). However, it was not possible to reach the color intensity of grapes.
Even if both methods have the potential to assess wine grape quality on 11 important parameters, the quality of the models generated in our study was dependent on the quality parameter, the type of grapes (color) and the method, except for fructose, TSS and Extractable Anthocyanin contents, which were equivalent. Thus, the glucose concentration and the Total Phenolic Index (TPI) were better assessed by Raman spectroscopy, whereas Extractable Phenolics content was better estimated by HSI for both white and red grapes as well as Total  Anthocyanin content. Tartaric acid, Total Flavonoids, Color Intensity and extractable Flavonoids were better assessed by HSI for red grapes but by Raman for white grapes.
The quality of the generated models was yet dependent on the color of grapes and the parameter considered. More data would be necessary to strengthen the models but the proof of concept was successful with this study

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Maury Chantal¹, Gabrielli Mario², Ounaissi Daoud¹, Lançon-Verdier Vanessa¹, Julien Séverine¹and Le Meurlay Dominique ¹

¹USC 1422 GRAPPE, INRAE, Ecole Supérieure d’Agricultures, SFR 4207 QUASAV
²Dipartimento di Scienze e Tecnologie Alimentari per una filiera agro-alimentare Sostenibile, Università Cattolica del Sacro Cuore

Contact the author

Keywords

wine grape, hyperspectral imaging, Raman spectroscopy, phenolics, composition

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Studio dell’ambiente viticolo attraverso la parametrazione (punto di incrocio) delle curve di maturazione delle uve (pinot nero, oltrepo’ pavese pv italia settentrionale – 45° parallelo Nord)

Sono stati presi in considerazione alcuni dati agrometeorologici dell’Oltrepò Pavese (temperature e piovosità degli ultimi 80 anni) e gli studi delle curve di maturazione condotti in zona sul Pinot nero da spumante negli anni (1988-1991, 1999-2000, 2006-2008), si nota che l’aumento progressivo negli anni delle temperature attive (indice di Winkler) ha determinato un anticipo dell’invaiatura, definita dal parametro “punto di incrocio” (intersezione delle funzioni di zuccheri ed acidità nel tempo), con conseguente anticipo della data di vendemmia di circa 12-15 gg.

Read More

Sensory patterns observed towards the oxidation of white, rosé and sparkling wines: An exploratory study

Oxygen management is crucial in terms of wine quality. Even more for white and rosé wines, which are less protected against oxidation than reds due to the lower levels of antioxidant polyphenols. This need is due to the existence of equilibria between chemical forms depending on the redox potential.

Read More

Focus on terroir studies in the eger wine region of Hungary

In 2001, the Hungarian Ministry of Agriculture and Rural Development designated the Institute of Geodesy, Cartography and Remote Sensing (FÖMI) to elaborate a Geographic Information System (GIS) supported Vineyard Register (VINGIS) in Hungary. The basis of this work was a qualification methodology (vineyard and wine cellar cadastre system) dating back to several decades, however, in the 1980s and 1990s the available geographical maps and information technology did not provide enough accuracy for an overall evaluation of viticultural areas. The reason for the VINGIS elaboration and development was an obligation resulting from the EU membership to ensure the agricultural subsidies for the wine–viticulture sector.

Read More

New oenological criteria for selecting strains of Lachancea thermotolerans for wine technology

The study conducted various fermentations of different grape juices using various strains of Lachancea thermotolerans and one strain of Saccharomyces cerevisiae. Because of the new conditions caused by climate change, wine acidity must be influenced as well as the volatile profile. Non-Saccharomyces yeasts such as L. thermotolerans are real options to mitigate the impact of climate change in wine production.

Read More

2018 updates on the agronomic performances of fungus resistant wine grapes in Trentino (Italy)

On the market there are several wine grapes which are tolerant to the main fungal diseases. These varieties, commonly defined “resistant”, were developed in the grapevine breeding programs carried out mainly in Germany, France, Hungary and Italy. Some of these cultivars have been included in the national catalogues of wine grape varieties and have sometimes been allowed for specific kinds of wine. The VEVIR project, aimed at the enological evaluation of resistant vines, involves 33 cultivars achieved at the State Institute for Viticulture Freiburg in Germany, the Research Institute of Viticulture and Enology Pecs in Hungary and the Fondazione Edmund Mach S. Michele all’Adige (FEM) in Italy.

Read More