IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Infrared spectroscopy investigation of fresh grapevine organs for clustering and classification.

Infrared spectroscopy investigation of fresh grapevine organs for clustering and classification.


The spectral information acquired from fresh whole grapevine organs have yet to be fully explored. Infrared spectroscopy provides the means to rapidly measure fresh plant material and providing extensive information on the physical and chemical structure of samples. This study aimed to explore the spectra of fresh grapevine shoots, leaves, and berries throughout the growing season for clustering and classification. Sampling was performed across two vintages (2019-2020; 2020-2021) from November to March. Five locations, seven cultivars, and 17 commercial vineyards were included. Collection of whole shoots, including leaves and grape bunches, were performed on a monthly basis. The fresh grapevine organs were analysed using three spectroscopy methods within 24-36 hours of sampling. Mid-infrared (MIR) and near-infrared (NIR), making use of a solid probe (NIR-SP) and a rotating sphere (NIR-RS), were investigated. The raw spectra were firstly investigated using principal component analysis (PCA) followed by a more novel chemometric approach, unsupervised
self-organising maps (SOM). PCA as well as unsupervised SOM showed the most considerable grouping based on organ type. Additionally, the unsupervised SOM showed separation trends based on phenological stage. Investigation of the datasets per organ with SOM showed separation based on the phenological stage for berries and shoots, as well as shoots clustering based on lignification. Supervised SOM were examined for classification based on the observed clustering per organ type, phenological stage, and lignification. The accurate prediction of organ at 90.3% was possible for the NIR-SP dataset for 2019-2021. Overlapping of various phenological stages were seen for the grape berry datasets, but prediction improved to 85.6% for the NIR-RS 2019-2021 dataset when certain phenological
stages were grouped together. Accurate predictions of lignified and unlignified shoots were also seen for the NIR-SP 2019-2021 and NIR-RS 2020-2021 datasets at 74.4% and 89.9% respectively. The possibility of using spectral variable selection to improve the supervised SOM predictions were explored and promising results obtained for certain datasets. Following variable selection with OPLS-DA and S-plots, the prediction of shoots and leaves improved by 14% for the NIR-RS 2020-2021 dataset. The prediction of lignified and unlignified shoots improved considerably to 92.3% for the NIR-SP 2019-2021 dataset and 95.9% for the NIR-RS 2020-2021 dataset. This study showed the extensive information available in infrared spectra of fresh grapevine organs and how the information could be used to achieve important clustering and classifications objectives


Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article


Van Wyngaard Elizma¹, Blancquaert Erna¹, Nieuwoudt Hélène¹and Aleixandre-Tudo Jose Luis1,²

¹South African Grape and Wine Research Institute (SAGWRI), Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch, South Africa
²Instituto de Ingeniería de Alimentos para el Desarrollo (IIAD), Departamento de Tecnologia de Alimentos, Universidad Politécnica de Valencia, Valencia, Spain

Contact the author


Spectroscopy, grapevine organs, clustering, classification


IVAS 2022 | IVES Conference Series


Related articles…

Significance of factors making Riesling an iconic grape variety

Riesling is the iconic grape variety of Germany and accounts for 23% of the German viticulture acreage, which comprises 45% of the worldwide Riesling plantings. Riesling wines offer a wide array of styles from crisp sparkling wines to highly concentrated and sweet Trockenbeerenauslese or Icewines. However, its thin berry skin makes Riesling more vulnerable to detrimental environmental threats than other white wine varieties.  

Malolactic fermentation in wine production

What influence do these bacteria have on wines? What new bacteria are being studied to carry out this fermentation? Find below articles about malolactic fermentation published in our 3 media (OENO One, IVES Technical Reviews and IVES Conference Series). OENO One...

Metabolomics screening of Vitis sp. interspecific hybrids to select natural ingredients with cosmetic purposes

Introducing natural ingredients using green chemistry practices is a major challenge in cosmetics industry to follow the market trend. Among the plants of cosmetic interest, vine products show a remarkable diversity of natural substances with high potential for the cosmetic and dermatological sectors. To date, research focuses on well-known compounds like E-resveratrol and E-ε-viniferin,

WAC 2022: Abstracts are available on IVES Conference Series

In order to disseminate the scientific results presented during the WAC 2022 , the organizers have decided to share the abstracts of the oral communications and posters with Open Access on IVES Conference Series. The fifth edition of the International Conference...

Winemaking techniques and wine tasting methods at the end of the Middle Ages

Les pratiques de vinification et de dégustation du vin sont souvent perçues, à travers un discours marketing très puissant, sous l’angle d’une tradition millénaire qui perdure depuis le Moyen Âge. En Bourgogne, il est courant de rattacher les racines de ces pratiques à l’activité des institutions ecclésiastiques qui possédaient d