terclim by ICS banner
IVES 9 IVES Conference Series 9 Implementation of hyperspectral image analysis for evaluating table grape quality on bunch and berry level

Implementation of hyperspectral image analysis for evaluating table grape quality on bunch and berry level

Abstract

Typically, subjective, and visual methods are used by grape growers to assess harvest maturity. These methods may not accurately represent the maturity of an entire vineyard – especially if extensive and representative sampling was not used. New technologies have been investigated for improved harvest management decisions. Spectroscopy methods utilizing the near-infrared region of the light spectrum is one such technology investigated as an alternative to classic methods and particularly the application of hyperspectral imaging (HSI) has recently gained attention in research. HIS is a spectroscopic technique that obtains hundreds of images at different wavelengths collecting spectral data for each pixel in the sample i.e., providing both spectral and spatial data.
In this study HSI in the visible-near infrared (VNIR) and short-wave infrared (SWIR) regions was tested for determining total soluble solids (TSS), pH and total acidity (TA) of table grapes under laboratory conditions. Imaging of whole bunches as well as individual berries selected from top, middle and bottom positions of bunches was done. The bunches and berries were collected over multiple samples sessions throughout the 2022-23 and 2023-24 seasons allowing for fruit of various maturity levels (unripe though to harvest maturity) to be included. Spectral data was extracted from the images using MATLAB codes developed for this purpose using different analysis approaches. The resulting data is spatial and numerical yielding mean reflectance per pixel across points for entire bunches, and entire berries. Models for determining grape chemical composition were developed using ground-truthing data collected from the sampled fruit. Initial results indicate that this method could be suitable for determining grape ripeness on a bunch or berry level.

DOI:

Publication date: June 14, 2024

Issue: Open GPB 2024

Type: Poster

Authors

Talitha Venter1*, Rodrigo Oliva-Mancilla1,2, Fikile Wolela1, Eunice Avenant1,3, Carlos Poblete-Echeverría1 *

1 South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, South Africa, 7602
2 Global technical consultancies, 05 Barn Road, Bergvliet, Cape Town, South Africa, 7945
3 South African Table Grape Industry, PO Box 2932, Paarl, South Africa, 7620

Contact the author*

Keywords

table grapes, hyperspectral imaging, ripeness, quality, spectroscopy

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

Assessment of the impact of actions in the vineyard and its surrounding environment on biodiversity in Rioja Alavesa (Spain)

Traditional viticulture areas have experienced in the last decades an intensification of field practices, linked to an increased use of fertilisers and phytosanitary products, and to a more intensive mechanization and uniformization of the landscape. This change in management has sometimes led to higher rates of soil erosion andloss of soil structure, fertility decline, groundwater contamination, and to an increased pressure of pests and diseases. Additionally, intensification usually leads to a simplification of landscapes, of particular concern in prestigious wine grape regions where the economical revenue encourages the conversion of land use from natural habitats to high value wine grape production. To revert this trend, it is necessary that growers implement actions that promote biodiversity in their vineyards. The aim of this study is to assess the impact of the implementation of cover crops, vegetational corridors, dry stone walls and vineyard biodiversity hotspots estimated through the study of arthropods. The work has been carried out in four vineyards in Rioja Alavesa belonging to Ostatu winery, where these infrastructures were implemented in 2020. The presence and diversity of arthropods was studied by capturing them at different times in the season and at different distances from the infrastructure using pit-fall traps in the soil and yellow, white and blue chromatic traps at the canopy level. This is a preliminary study in which all adult insects were sorted to the taxonomic level of order and Coleoptera were classified to morphospecies. The results obtained show that there is a relationship between the basic characteristics of the vineyard and the arthropods captured, with a positive effect, although also dependent on the vineyard, of the presence of infrastructure.

A combination of biotechnology tools and coopers elements for an alternative the addition of SO2 at the end of the malolactic fermentation in red wines or at the “mutage” for the “liquoreux” wines

In red wines the post-MLF SO2 addition is an essential event. It is also the case for the “mutage” during the elaboration of the “liquoreux”. At these moments SO2 plays an antimicrobial action and an antioxidant effect. But at current pH of wines, ensuring a powerful molecular SO2 has become very difficult. Recent work on Brettanomyces strains have also shown that some strains are resistant up to 1.2 mg / L of molecular SO2. It’s also the case of the some Saccharomuces or Zygosaccharomyces strains suitable to re-ferment “liquoreux” wines after the “mutage”.

Analisi delle modalita’ d’interazione tra conoscenza dl un territorio e gestione dei suoi aspetti enoturistici relativamente ad una regione (Toscana)

Il Turismo negli anni 2000 si appresta ad essere la più vasta ed estesa impresa presente nel mondo. Se a cio si aggiunge il fatto che il tempo libero risulta essere, per la maggior parte delle persone, la principale aspirazione da considerare ben oltre il proprio benessere eco­nomico, ci si rende conto del perché di una crescente domanda di ecoturismo. Un viaggiare sempre più accorto aile valenze ambientali e tipiche di un territorio.

Vitamins in musts : an unexplored field

Vitamins are major compounds, involved in several prime yeast metabolic pathways. Yet, their significance in oenology has remained mostly unexplored for several decades and our current knowledge on the matter still remaining obscure to this day. While the vitaminic contents of grape musts have been approached in these ancient investigation

Evaluation of “Accentuated cut edges” technique on the release of varietal thiols and their precursors in Shiraz and Sauvignon blanc wine production

Accentuated cut edges (ACE) is a novel grape crushing technique used sequentially after a conventional crusher to increase the extraction rate and content of polyphenolics, as shown for Pinot noir wine. This inspired us to apply the technique during Shiraz and Sauvignon blanc winemaking, primarily to assess its impact on the extraction of varietal thiol precursors in grape must/juice and formation of varietal thiols in the resultant wines