Non-destructive determination of grape berry sugar concentration using visible/near infrared imaging and possible impact on wine quality
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Magali Lafontaine
Magali Lafontaine received her MSc at the Bordeaux Sciences Agro in France, she is now working for the Hochschule Geisenheim University in Germany. Main research areas: vine vigor and its variability, new technologies in viticulture, particularly on grape sorting and its impact on wine quality.
Center for Viticulture and Horticulture – Institute for General and Organic viticulture, Von Lade Str. 1, 65366 Geisenheim, Germany, Tel.: +49-6722-502-165
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Zrinka Bockaj
Zrinka Bockaj works as a developer engineer at AVL Graz for dual-clutch and automatic transmission software functions. She did her master thesis at Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB) in Karlsruhe with the topic: Design of an interference filter for grape sorting. Main research areas: hyperspectral imaging, multivariate data analysis, optimization algorithms, functional modelling and simulation.
AVL List GmbH, Hans-List-Platz 1, 8020 Graz, Austria, Tel.: +43 (664) 8379340
Maximilian Freund is a scientist at the Institute of Enology of the Hochschule Geisenheim University. Main research areas: grape treatment, winemaking, management systems for environmental and food safety.
Center for Wine Research and Process Engineering of Beverages – Institute of Enology, Blaubachstr. 19, 65366 Geisenheim, Germany, Tel.: +49-6722-502-183
Kai-Uwe Vieth works at the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB) as Group Manager for the department Visual Inspection Systems. Main research areas: image processing, hyperspectral imaging, development of bulk goods sorting systems.
Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB), Fraunhoferstr. 1, 76131 Karlsruhe, Germany, Tel.: +49 721 6091-279
Christian Negara is a research assistant at the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB). Main research areas: ellipsometry, hyperspectral imaging, multivariate statistics.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB), Fraunhoferstraße 1, 76131 Karlsruhe, Germany, Tel.: +49-721-6091-567, Fax: +49-721-6091-413
Thomas Längle is adjunct professor at the Karlsruhe Institute of Technology (KIT), Karlsruhe, and the head of the business unit “Vision Based Inspection Systems” (SPR) at the Fraunhofer IOSB in Karlsruhe, Germany. His research interests include different aspects of image processing and real-time algorithms for inspection systems.
adjunct professor at the Karlsruhe Institute of Technology (KIT), Department of Informatics, Institute for Anthropomatics and Robotics, 76131 Karlsruhe, Germany
Abstract
Reducing heterogeneity in harvest material would be beneficial for wine quality and this goal may be achieved through advanced berry sorting systems. The general aim was to assess if a relationship could be found between sugar concentration and hyperspectral images. Grapes were picked at different stages of maturity and the berries were sorted according to their size and density. Hyperspectral images of the berry subsamples were obtained in the vis/NIR wavelength range with a complete spectrum from 400 nm to 2500 nm. Our results showed that vis/NIR can be used to improve the segregation of berries from all tested grape varieties based on their sugar concentration. All berries from all 12 grape varieties were used to train the regression model and the predictive power was tested on all each grape variety separately, while later validated on each variety separately, proving the possibility of using a general regression model with constant parameters to predict sugar concentration. Finally, the impact on quality was tested for red wines. Pinot noir berries with higher sugar concentrations presented more color since anthocyanin concentration was higher. Nevertheless, tannin concentration in skins and seeds tended to decrease. Berries with higher sugar concentration resulted in wines with higher anthocyanin and lower tannin concentration.
Zusammenfassung
Mit Unterstützung optischer Sortiersysteme könnte die Heterogenität des Ernteguts reduziert und damit ein Schritt zur Erhöhung der Weinqualität geleistet werden. Das allgemeine Ziel des Projektes war es, zu beurteilen, ob ein Zusammenhang zwischen Zuckerkonzentration der Beeren und hyperspektraler Bilder dieser Beeren gefunden werden kann. Dafür wurden Trauben verschiedener Entwicklungsstadien während der Reife entnommen und die Beeren entsprechend ihrer Größe und Dichte sortiert. Hyperspektrale Bilder der Beerenproben wurden im VIS/NIR-Wellenlängenbereich mit einem vollständigen Spektrum von 400 nm bis 2500 nm aufgenommen. Die Ergebnisse zeigen, dass die VIS/NIR-Technologie die Sortierung von Beeren unterschiedlicher Rebsorten auf der Basis ihrer Zuckerkonzentration ermöglicht. Die Ergebnisse aller zwölf untersuchten Rebsorten wurden verwendet, um das Regressionsmodell zu erstellen. Anschließend wurde die Vorhersagekraft für jede Rebsorte separat getestet und validiert. Durch die Nutzung eines auf gleichen Parametern basierenden Regressionsmodells über alle Rebsorten hinweg wird eine einfache, Rebsorten unabhängige Vorhersage der Zuckerkonzentration der Beeren ermöglich. In einem Praxisversuch wurde der Einfluss einer Beerensortierung auf die Rotweinqualität der Rebsorte Pinot noir getestet. Beeren mit höherem Zuckergehalt wiesen aufgrund der höheren Anthocyan-Konzentration mehr Farbe auf. Gleichzeitig zeigten diese tendenziell niedrigere Tanningehalte in Beerenhaut und Kernen. Die Weine aus Beeren mit höherer Zuckerkonzentration spiegelten diese Beobachtungen wider; sie zeigten eine höhere Anthocyan- und eine niedrige Tanninkonzentration.
Funding statement: This project was financed by a German ZIM (The Central Innovation Program – Zentrales Innovationsprogramm Mittelstand) research project of the BMWi (Federal Ministry of Economics and Technology – Bundesministerium für Wirtschaft und Technologie, Grant/Award Number: KF 3121701WM3).
About the authors
Magali Lafontaine received her MSc at the Bordeaux Sciences Agro in France, she is now working for the Hochschule Geisenheim University in Germany. Main research areas: vine vigor and its variability, new technologies in viticulture, particularly on grape sorting and its impact on wine quality.
Center for Viticulture and Horticulture – Institute for General and Organic viticulture, Von Lade Str. 1, 65366 Geisenheim, Germany, Tel.: +49-6722-502-165
Zrinka Bockaj works as a developer engineer at AVL Graz for dual-clutch and automatic transmission software functions. She did her master thesis at Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB) in Karlsruhe with the topic: Design of an interference filter for grape sorting. Main research areas: hyperspectral imaging, multivariate data analysis, optimization algorithms, functional modelling and simulation.
AVL List GmbH, Hans-List-Platz 1, 8020 Graz, Austria, Tel.: +43 (664) 8379340
Maximilian Freund is a scientist at the Institute of Enology of the Hochschule Geisenheim University. Main research areas: grape treatment, winemaking, management systems for environmental and food safety.
Center for Wine Research and Process Engineering of Beverages – Institute of Enology, Blaubachstr. 19, 65366 Geisenheim, Germany, Tel.: +49-6722-502-183
Kai-Uwe Vieth works at the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB) as Group Manager for the department Visual Inspection Systems. Main research areas: image processing, hyperspectral imaging, development of bulk goods sorting systems.
Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB), Fraunhoferstr. 1, 76131 Karlsruhe, Germany, Tel.: +49 721 6091-279
Christian Negara is a research assistant at the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB). Main research areas: ellipsometry, hyperspectral imaging, multivariate statistics.
Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB), Fraunhoferstraße 1, 76131 Karlsruhe, Germany, Tel.: +49-721-6091-567, Fax: +49-721-6091-413
Thomas Längle is adjunct professor at the Karlsruhe Institute of Technology (KIT), Karlsruhe, and the head of the business unit “Vision Based Inspection Systems” (SPR) at the Fraunhofer IOSB in Karlsruhe, Germany. His research interests include different aspects of image processing and real-time algorithms for inspection systems.
adjunct professor at the Karlsruhe Institute of Technology (KIT), Department of Informatics, Institute for Anthropomatics and Robotics, 76131 Karlsruhe, Germany
Acknowledgement
The authors like to thank the team of the Hochschule Geisenheim University for the analysis, together with the industrial partners ARMBRUSTER Kelterei-Technologie GmbH and Ingenieurbüro Waidelich.
©2015 Walter de Gruyter Berlin/Boston
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Articles in the same Issue
- Frontmatter
- Editorial
- Optical characterization of materials
- Beiträge
- Spectral and geometric aspects of mineral identification by means of hyperspectral fluorescence imaging
- Single-shot LIBS spectral quality for waste particles in open air
- Hyperspectral imaging applied to end-of-life (EOL) concrete recycling
- Protecting the food supply chain: Utilizing SERS and portable Raman spectroscopy
- Non-destructive determination of grape berry sugar concentration using visible/near infrared imaging and possible impact on wine quality
- Visible hyperspectral imaging for lamb quality prediction
- Near infrared spectroscopy as a tool for in-line control of process and material properties of PLA biopolymer
- Large scale classification of spectral signatures
