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IVES 9 IVES Conference Series 9 EFFECT OF DIFFERENT TEMPERATURE AND WATER-LOSS DEHYDRATION CONDITIONS ON THE PATTERN OF FREE AND GLYCOSYLATED VOLATILE METABOLITES OF ITALIAN RED GRAPES

EFFECT OF DIFFERENT TEMPERATURE AND WATER-LOSS DEHYDRATION CONDITIONS ON THE PATTERN OF FREE AND GLYCOSYLATED VOLATILE METABOLITES OF ITALIAN RED GRAPES

Abstract

Post-harvest grape berries dehydration/withering are worldwide applied to produce high-quality sweet and dry wines (e.i., Vin Santo, Tokaji, Amarone della Valpolicella). Temperature and water loss impact grape metabolism [1] and are key variables in modulating the production of grape compounds of oenological interest, such as Volatile Organic Compounds (VOCs), secondary metabolites responsible for the aroma of the final wine.

The aim of this research was to assess the impact of post-harvest dehydration on free and glycosylated VOCs of two Italian red wine grapes, namely Nebbiolo and Aleatico, dehydrated in tunnel under controlled condition (varied temperature and weight-loss, at constant humidity and air flow). From these grapes Sforzato di Valtellina Passito DOCG and Elba Aleatico Passito DOCG, respectively.

The experimental plan followed a “Temperature (10°C, 15°C, 20°C, 25°C) x Weight loss (0%, 10%, 20%, 30%)” factorial design. Skin and juice free and glycosylated VOCs of grape berries were separately analysed by Solid Phase Extraction/Gas Chromatography–Mass Spectrometry (SPE/GC-MS) [2].

Results showed that skin and juice samples are well discriminated in both varieties, with skins exhibiting a greater aromatic richness, especially in terms of bound VOCs. In Nebbiolo grapes, weight loss showed a greater influence than temperature on free volatiles. This trend was not observed on free VOCs of Aleatico grapes, that were treated with more stressful dehydration conditions of temperature (15°C, 25°C) and weight loss (20%, 30%) compared to Nebbiolo grapes (10°C, 20°C; 10%, 20%).

Temperature seems to play an important role on bound VOCs of both grapes, albeit in a different form. In Nebbiolo grapes, low temperatures (10°C) showed positive correlations with the accumulation of aroma glycosidic precursors. In the case of Aleatico, which is a semi-aromatic variety, dehydration temperatures, appear to modulate terpenes pattern regardless of weight loss. Specifically, samples dehydrated at 15°C correlated with betalinalool, epoxylinalool, cis- and trans-linalool oxide, and geranic acid, while 25°C ones with cis- and trans-geraniol, cis- and trans-citral, α-terpineol, and citronellol.

These results are of interest for optimizing the grape dehydration process not only in an optic of management of product characteristics and varietal oenology, but also in a prospective of management of energy resources needed under controlled dehydration conditions.

 

1. Costantini et al., 2006. DOI: 10.1021/jf053117l
2. Piombino et al., 2022. DOI: 10.1111/ajgw.12521

DOI:

Publication date: February 9, 2024

Issue: OENO Macrowine 2023

Type: Article

Authors

Paola Piombino1, Elisabetta Pittari1, Alessandro Genovese2, Andrea Bellincontro3, Fabio Mencarelli4, Luigi Moio1

1. Department of Agricultural Sciences, Division of Vine and Wine Sciences, University of Naples Federico II, Avellino 83100, Italy
2. Department of Agricultural Sciences, Division of Food Science and Technology, University of Naples Federico II, Portici (NA), 80055, Italy
3. DIBAF, University of Tuscia, Via De Lellis, 01100 Viterbo, Italy
4. Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, Pisa 56124, Italy

Contact the author*

Keywords

grapes dehydration, secondary metabolites, aromas, SPE/GC-MS

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

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