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…

Cover crops under-vine impact on grapevine performance and vineyard soil microorganisms is highly affected by edaphoclimatic conditions at a regional scale 

Soil management through cover crops can influence the cycle of nutrients, promote water infiltration, decrease erosion, and enhance the soil microbiota biodiversity, improving the grapevine performance. However, the area under the vines tends to be left bare by applying herbicides or tillage to avoid competition with the crop in semi-arid climates. Use of covers under-vine might be an alternative to these practices aiming at grapevine quality and soil health improvement. The aim of this research was to study the implications of soil management under the vines (cultivation and cover crops) on growth, yield, berry composition and soil microbial communities. A cover crop composed by a mixture of legumes was sown and compared with a control (cultivation), which includes frequent tillage to keep the soil bare, in three areas characterized by different edaphoclimatic conditions in the region of Navarra.

Metabolomic profiling of botrytized grape berries: unravelling the dynamic chemical transformations during noble rot

Botrytis cinerea, a fungal pathogen commonly known as grey mold, which under specific climatic conditions can develop into a desirable form known as noble rot. In this process the fungus penetrates the grape skin, allowing water evaporation and concentration of sugars and flavors, while profoundly affects the metabolite composition of grapes, leading to the production of unique and desirable compounds in the resulting wines. The result is a unique and complex wine with a luscious sweetness, heightened aromatics, and a distinct character.

Vineyard Landscape in Vale dos Vinhedos: Pressure and Protection

The region with Origin Indication Vale dos Vinhedos (IPVV) is located in the cities of Bento Gonçalves, Garibaldi and Monte Belo do Sul. It was established in November 2002, through an act of Instituto Nacional de Propriedade Industrial, according to Resolução INPI Nº. 75, of 2000, and Law Nº. 9.279 of 1996. The changes on the grape growing and wine making in the last 15 years, with the expansion of grapevines Vitis viníferas cultivation, the installation of several modern family wine companies, making wine with competitive quality, among other aspects, have enabled the implementation of concepts of Geographical Indications.

Unveiling the secrets of catechin: insights from NMR spectroscopy

Catechins, a class of flavonoids found in foods and beverages such as wine and tea, exhibit potent antioxidant properties that contribute to various health benefits.[1]

Time stability of visitors’ preferences for preserving the worldwide cultural landscape alto douro wine region

The Alto Douro Wine Region (ADWR) was classified a world heritage site, specifically as a cultural landscape, by UNESCO, in 2001. The well known “Porto Wine” and other high quality wines are produced in the Douro region. As an attraction and touristic site, the cultural site has to meet the needs of more demanding visitors and to compete with a growing number of cultural sites, also classified by UNESCO. To achieve this goal, landscape managers and public authorities have much to profit from knowing and understanding visitors’ preferences regarding the attributes associated to its outstanding universal value.