 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

Contact the author

Keywords

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

Citation

Evaluation of wood starch content on bench grafting success rate in grapevine

Since the emergence of phylloxera, grafting has been the most used propagation method in viticulture. Despite all the improvement measures implemented in the nurseries, it is frequent that graft success rates vary depending on the nursery process and scion/rootstock combinations. The reasons behind this unsatisfactory behaviour are still unknown and can be diverse, although carbohydrate reserves might be hypothesised to be crucial, since callus, root, and new tissue formation will be built based on them. In order to identify the effect of carbohydrates on grafting success, nine combinations were established based on the starch content in grapevine scionwoods (cv. Tempranillo clone VN69) and rootstocks cuttings (110 Richter clone 237) used for grafting: Low (L), Medium (M), High (H).

Proteomic profiling of grape berry presenting early loss of mesocarp cell vitality

From fruit set to ripening, the grape berry mesocarp experiences a wide range of dynamic physical, physiological, and biochemical changes, such as mesocarp cell death (MCD) and hydraulic isolation. The premature occurrence of such events is a characteristic of the Niagara Rosada (NR) variety, utilised as table grapes and winemaking. In our opinion, the onset of ripening would not cause MCD, but a down-regulation of respiratory enzymes during the early loss of cell viability, while maintaining membrane integrity. For this, we investigated three distinct developmental stages (green (E-L33), veraison (E-L35), and ripe (E-L39)) of NR berries by label-free proteomics, enzymatic respiratory activity and outer mesocarp imaging. Cell wall-modifying proteins were found to accumulate differently throughout ripening, while cytoplasmic membranes continue intact.

Post-spring frost canopy development and fruit composition in cv. Barbera grapevines

One of the effects of warming trends is the advance of budburst, increasing the frequency of spring frost-related damage. In April 2021, a severe frost event affected central and northern italian viticulture. In a cv. Barbera vineyard located in the Colli Piacentini wine district, after such occurrence, vines were tracked and growth of primary bud shoots (PBS), secondary bud shoots (SBS), and suckers (SK) was monitored, as well as their fruitfulness and fruit composition. Vine performances were then compared to those of the previous year, when no post-budburst freezing temperatures occurred. The goal of the study was to evaluate the efficacy of SBS in restoring yield loss due to PBS injuries and analyze respective contribution to fruit composition.

Soil Temperature and Climate Change: Implications for Mediterranean Vineyards

More frequent and extreme temperatures and droughts pose challenges to the wine sector in Mediterranean Europe. Soil is crucial to sustain the equilibrium of ecosystems, economic growth and people’s prosperity worldwide. In viticulture, soils are a major component of the terroir and do influence vine’s growth, yield and berry composition. Soil temperature (ST) affects soil´s physical, chemical and biological processes and also crop growth. The impact of ST becomes even stronger when dealing with row crops such as grapevine, when considering the increased exposition to radiation. However, the impact of ST on crop performance remains poorly described, especially for extreme climatic conditions.

Evaluating the greenness of wine analytical chemistry: A new metric approach

Wine is a complex matrix whose composition depends on climatic, agricultural, and winemaking factors, making quality control and authenticity assessment critical in the global market.