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.

Download the abstract

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…

Q-NMR measurements: quantitative analysis of wine composition applied to Bordeaux red wines authenticity control

Traceability of wine is today a consumer demand and a scientific challenge. The methods of analysis must be able to control three fundamental parameters: the geographical origin, the grape varieties, and the vintage.

Read More

Terroir, sol et sous-sol : principes de modélisation spatiale de quelques paramètres physiques caractérisant le substrat altéré dans les régions viticoles établies sur socle ancien

For several years, the development of computer resources, and in particular of Geographic Information Systems, have allowed the emergence of a new approach to the analysis and characterization of wine-growing areas (Morlat, 1989; Laville, 1990). These methods, which make it possible to identify homogeneous areas or units of terroir, are based on crossing, statistical analysis (in particular Principal Component Analysis: PCA) and the integration of parameters describing the natural environment in which develop the vine.

Read More

Multi-omics methods to unravel microbial diversity in fermentation of Riesling wines

Wine aroma is shaped by the wine’s chemical compositions, in which both grape constituents and microbes play crucial roles. Although wine quality is influenced by the microbial communities, less is known about their population interactions.

Read More

IMPACT OF RHIZOPUS AND BOTRYTIS ON WINE FOAMING PROPERTIES

A lot of work has been done on the impact of Botrytis on the foam of sparkling wines. This work often concerns wines produced in cool regions, where Botrytis is the dominant fungal pathogen. However, in southern countries such as Spain, in particularly hot years such as 2022, the majority fungal pathogen is sometimes Rhizopus. Like Botrytis, Rhizopus is a fungus that produces an aspartic protease.

Read More

INFLUENCE OF CHITOSAN, ABSCISIC ACID AND BENZOTHIADIAZOLE TREATMENTS ON SAVVATIANO (VITIS VINIFERA L.) WINES VOLATILE COMPOSITION PROFILE

In the last decades the use of bioestimulants in viticulture have been promoted as alternative to conven- tional pesticides. Moreover, as bioestimulants promote the biosynthesis of secondary metabolites in grape berries, several studies had investigated their influence on the accumulation of phenolic com- pounds (Monteiro et al., 2022). However, few studies, so far, are focused on the accumulation of the vo- latile compounds and their impact on the produced wines (Giménez-Bañón et al., 2022; Gomez- Plaza et al., 2012; Ruiz Garcia et al., 2014).
This study was conducted in a single vineyard of white autochthonous grapevine variety Savvatia- no (Vitis vinifera L.) in Muses Valley (Askri, Viotia, Greece). Chitosan (CHT), Abscisic Acid (ABA) and Benzothiadiazole (BTH) were applied.

Read More