terclim by ICS banner
IVES 9 IVES Conference Series 9 ASSESSMENT OF GRAPE QUALITY THROUGH THE MONITORING OFPHENOLIC RIPENESS AND THE APPLICATION OF A NEW RAPID METHOD BASED ON RAMAN SPECTROSCOPY

ASSESSMENT OF GRAPE QUALITY THROUGH THE MONITORING OFPHENOLIC RIPENESS AND THE APPLICATION OF A NEW RAPID METHOD BASED ON RAMAN SPECTROSCOPY

Abstract

The chemical composition of grape berries at harvest is one of the key aspects influencing wine quality and depends mainly on the ripeness level of grapes. Climate change affects this trait, unbalancing technological and phenolic ripeness, and this further raises the need for a fast determination of the grape maturity in order to quickly and efficiently determine the optimal time for harvesting. To this end, the characterization of variety-specific ripening curves and the development of new and rapid methods for determining grape ripeness are of key importance.

As part of this ongoing project, 35 vineyards (26 cv. Nebbiolo, 9 cv. Barbera) from Langhe, Roero, and Monferrato terroirs (Piemonte, Italy) were monitored during two consecutive vintages (2021-2022). The Nebbiolo vineyards were further classified, based on historical data, into ripening classes according to the harvest period estimation (early, medium, and late Nebbiolo). To study the evolution of grape ripening, four grape samples were taken from each vineyard during the ripening period (mid-August – late September), and grape quality assessment was performed by means of parameters commonly used in wine industry: juice technological maturity and phenolic ripeness parameters (total and extractable anthocyanins-EA%, share of tannins from seeds-Mp%). Preliminary results showed differences among cultivars and ripening classes, with a strong influence of the climatic conditions of the vintage, being both hot vintages with a strong water deficit (and decrease in berry weights and anthocyanin accumulation) for the 2022 vintage.

To have a more in-depth insight into the phenolic changes of the grapes during ripening, total extractions of the skins and seeds phenolics were carried out to better characterize the composition of Nebbiolo and Barbera berries. Lastly, this data was used to train a new approach based on Raman spectroscopy (RS), in an attempt to develop a method for the rapid determination of berry quality. At each sampling point, the acquisition of the grape Raman spectra was carried out in parallel with the other chemical analyses, developing a prediction model by correlating technological and phenolic ripening parameters with RS results.

Acknowledgments: The QUALSHELL project is funded by the PSR 2014-2020 Regione Piemonte (Italy), op. 16.1, European Agricultural Fund for Rural Development. We thank Martina Tarditi, Daniele Ronco, Alessandro Bottallo and the wineries supplying grape samples.

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Lorenzo Ferrero¹, Alessio Sacco², Massimo Guaita³, Walter Salvano⁴, Andrea M. Rossi², Luca Rolle¹, Antonella Bosso³, Simone Giacosa¹

1. Università degli Studi di Torino, Dipartimento di Scienze Agrarie, Forestali e Alimentari. Corso Enotria 2/C, 12051 Alba, Italy
2. Istituto Nazionale di Ricerca Metrologica. Strada delle Cacce 91, 10135 Torino, Italy
3. Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca Viticoltura ed Enologia. Via P. Micca 35, 14100 Asti, Italy
4. Terre del Barolo. Via Alba-Barolo 8, 12060 Castiglione Falletto, Italy

Contact the author*

Keywords

Grape quality, Phenolic ripeness, Anthocyanins, Red wines

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

OENOLOGICAL STRATEGIES FOR THE REMOVAL OF PINKING IN WHITE WINE

The pinking of in white wine is the turning of color from yellow to salmon hue. White wines obtained from certain grape varieties (e.g. Chardonnay, Sauvignon blanc, Riesling, Trebbiano di Lugana) showed to be susceptible to pinking [1] that has been evaluated by an assay providing the addition of hydrogen peroxide. Even if its appearance does not seem to affect the sensory properties [2], strategies are necessary for its removal. Nowadays, the treatment with polyvinylpolipirroline (PVPP) was reported to significantly decrease the pink color [3].

Read More

Searching for the sweet spot: a focus on wine dealcoholization

It is well known that the vinification of grapes at full maturation can produce rich, full-bodied wines,
with intense and complex flavour profiles. However, the juice obtained from such grapes may have very
high sugar concentration, resulting in wines with an excessive concentration of ethanol. In addition, the decoupling between technological maturity and phenolic/aromatic one due to global warming, exacerbates this problem in some wine-growing regions. In parallel with the increase of the mean alcohol content of wines on the market, also the demand for reduced alcohol beverages has increased in recent years, mainly as a result of health and social concerns about the risks related to the consumption of alcohol.

Read More

VOLATILE COMPOSITION OF WINES USING A GC/TOFMS: HS-SPME VS MICRO LLE AS SAMPLE PREPARATION METHODOLOGY

Wine aroma analysis can be done by sensorial or instrumental analysis, the latter involving several me-thodologies based on olfactometric detection, electronic noses or gas chromatography. Gas Chromatography has been widely used for the study of the volatile composition of wines and depending on the detection system coupled to the chromatographic system, quantification and identification of individual compounds can be achieved.

Read More

IDENTIFICATION OF NEW RESVERATROL DERIVATIVES FORMED IN RED WINE AND THEIR BIOLOGICAL PROPERTIES

Stilbenes are natural bioactive polyphenols produced by grapevine. Recently, we have reviewed the na- tural presence of these compounds in wines [1]. This study showed that the resveratrol and its glycoside, the piceid, are the most abundant stilbenes in wines. Resveratrol is a well-known stilbene with a wide range of biological activities. Due to its specific structure, resveratrol can be oxidized in wines to form various derivatives including oligomers [2]. In this study, we investigate the resveratrol and piceid transformation in wines.

Read More

CHARACTERISTIC EXTRACTION OF THE PHENOL COMPOUNDS IN KOSHU (VITIS VINIFERA CV.) WINE DURING THE MACERATION

Koshu is one of the indigenous grape variety that has been grown in Japan for more than one thousand years. Recent research showed that it has 70% of Vitis vinifera genes. In 2010, the Koshu variety was included in ‘International List of Vine and Varieties and their Synonyms’ managed by the ‘International Organisation of Vine and Wine’ and has further fueled its popularity in Japan. It is the most cultivated variety for winemaking in Japan.
Koshu berries have light purple skins. The variety is mainly used to produce white wines such as an aromatic wine and a wine produced by sur lie method although various styles are produced.

Read More