 IVES 9 IVES Conference Series 9 Phenolic, antioxidant, and sensory heterogeneity of oenological tannins: what are their possible winemaking applications?

Phenolic, antioxidant, and sensory heterogeneity of oenological tannins: what are their possible winemaking applications?

Abstract

AIM: The aim of this work was to characterize 18 oenological tannins by the polyphenolic, antioxidant, and sensory point of view. These properties have been evaluated in model wine solution as well as in red wine added with these tannins to observe matrix effects and therefore to assess their performances in a real condition.

METHODS: Polyphenolic content (A280, Folin-Ciocalteu, proanthocyanidins assay) and antioxidant properties (ABTS, DPPH, FRAP, CUPRAC) were studied in a model wine solution (12 % ethanol, 4 g/L tartaric acid, pH 3.5). Bitterness and astringency sensory analysis (Descriptive Analysis) of selected formulations (40 g/hL) was performed in water and in red wine. After 1 month, the tannin-added wines were evaluated in terms of polyphenolic content (A280), antioxidant capacity (DPPH, FRAP), total anthocyanins, and polymerized pigments.

RESULTS: Antioxidant properties of oenological tannins and their influence on wine characteristics were strongly affected firstly by their polyphenolic richness, followed by their origin. In particular, the great antioxidant capacity of hydrolysable tannins was evident in both model wine solutions and wines after one month. Ellagitannins, thanks to this property, also led to an increased percentage of wine polymeric pigments with respect to the control whereas gallotannins showed low polymerization ability. Good performances were evidenced also by Acacia tannins additions in terms of increased polymeric pigments ratio. Moreover, quebracho formulations showed the highest perceived astringency and bitterness, but only in water solutions. In the same medium, ellagitannins exhibited a low value of bitterness and astringency but, on the contrary, they were perceived as astringent in red wine highlighting a significant matrix effect.

CONCLUSIONS

Phenolic content and antioxidant properties of tannin formulations in model wines are correlated with the characteristics of wines after one month. Among others, ellagitannins confirmed their potentialities in added wine regarding increased antioxidant capacity and polymeric pigments ratio. Nevertheless, astringency and bitterness are affected in different extent by the matrix, highlighting the influence of wine features on the final product sensory properties

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Luca Rolle

University of Turin – Department of Agricultural, Forest and Food Sciences,Maria Alessandra PAISSONI, University of Turin, Italy Giovanni BITELLI, University of Turin, Italy Mar VILANOVA, CSIC- Misión Biológica de Galicia, Spain Carlo MONTANINI, AEB S.p.A., Italy Simone GIACOSA, Università degli Studi di Torino, Italy Luca ROLLE, University of Turin, Italy Susana RÍO SEGADE, University of Turin, Italy

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Keywords

oenological tannins, phenolic compounds, antioxidant capacity, astringency, descriptive analysis

Citation

Oxygen consumption by diferent oenological tanins in a model wine solution

INTRODUCTION: Oenological tannins are widely used in winemaking to improve some characteristics of wines [1] being the antioxidant properties probably one of the main reasons [2]. However, commercial tannins have different botanical sources and chemical composition [3] which probably determines different antioxidant potential. There are some few references about the antioxidant properties of commercial tannins [4] but none of them have really measured the direct oxygen consumption by them. The aim of this work was to measure the kinetics of oxygen consumption by different commercial tannins in order to determine their real capacities to protect wine against oxygen. MATERIAL AND METHODS: 4 different commercial tannins were used: T1: condensed tannin from grape seeds, T2: gallotannin from chinese gallnuts, T3: ellagitannin from oak and T4: tannin from quebracho containing condensed tannins and ellagitannins.

Phenolic composition of Tempranillo Blanco grapes changes after foliar application of urea

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