Changes in Skin Flavanol Composition as a Response to Ozone-Induced Stress during Postharvest Dehydration of Red Wine Grapes with Different Phenolic Profiles.

Susana Río Segade,Vincenzo Gerbi,Simone Giacosa,Maria Alessandra Paissoni,Luca Rolle,Ana Belén Bautista-Ortín,Encarna Gómez-Plaza

doi:10.1021/acs.jafc.0c04081

Susana Río Segade, Vincenzo Gerbi + Show 5 more

Open Access

https://doi.org/10.1021/acs.jafc.0c04081

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Abstract

In this study, the combined effect of partial postharvest dehydration and long-term ozone treatment was evaluated at 10 and 20% weight loss as a strategy to induce compositional changes in grape skin flavanols. Two separate trials were carried out in thermohygrometric-controlled chambers at 20 °C and 70% relative humidity. The first trial was conducted under an ozone-enriched atmosphere at 30 μL/L, whereas the second trial was performed under an air atmosphere as a control. Two red wine grape varieties were studied, Barbera and Nebbiolo (Vitis vinifera L.), for their different phenolic composition. Berry skin flavanol composition was determined by high-performance liquid chromatography after phloroglucinolysis and size-exclusion chromatography. The results showed that dehydration and ozone effects were variety-dependent. In Barbera skins, being characterized by lower proanthocyanidin contents, the two effects were significant and their combination showed interesting advantages related to lower proanthocyanidin loss as well as higher prodelphinidin and lower galloylation percentages. In Nebbiolo, skin flavanol composition was barely affected.

Highlights

The composition and content of flavan-3-ols in red wines are gaining increasing interest in the last few years as a consequence of their direct impact on important sensory properties, such as bitterness, astringency, and structure.[1]
Six sample boxes were dehydrated under an ozone-enriched atmosphere at 30 μL/L using a continuous 120 m3/h flow produced by an ozone generator (C32-AG, Industrie De Nora Spa, Milan, Italy) with a nominal production capacity of 32 g of O3/h:18,21 the first three boxes up to 10% weight loss (WL) and the other three boxes up to 20% WL
Barbera berry skins presented a higher content of total flavonoids with respect to Nebbiolo when considering skin fresh weight (TF, 33.60 versus 27.30 mg/g of berry skins fw, respectively)

Summary

Introduction

The composition and content of flavan-3-ols in red wines are gaining increasing interest in the last few years as a consequence of their direct impact on important sensory properties, such as bitterness, astringency, and structure.[1]. PAs of Nebbiolo skins presented a higher mDP value than those of Barbera and different trends were highlighted for the two varieties during postharvest dehydration.

Results

Conclusion