Macrowine 2021
IVES 9 IVES Conference Series 9 Mean polymerization degree of proanthocyanidins of grape seeds, skins and wines from Agiorgitiko (cv. Vitis vinifera): Differences among vintages

Mean polymerization degree of proanthocyanidins of grape seeds, skins and wines from Agiorgitiko (cv. Vitis vinifera): Differences among vintages

Abstract

Grape phenolic compounds are very important constituents of red wine because, in addition to their antioxidant properties, they contribute to color, astringency and bitterness, oxidation reactions, interactions with proteins and ageing behavior of wines. The aim of our study was to assess the structural characteristics of grape and wine proanthocyanidins of Agiorgitiko variety and to evaluate the influence of the vintage year. Twelve vineyard locations were designated in the Nemea wine region. For three consecutive years (2012-2014), the grapes were harvested at technological maturity and the method of phloroglucinolysis was employed to determine the mean degree of polymerization (mDP) and subunit composition of the samples. Vintages 2012 and 2014 were characterized by extended botrytis infection, delayed sugar maturity and unripe tannins. In contrast, in 2013 the weather conditions were ideal, resulting in full sugar maturity, low botrytis infection and extended and full tannin maturation. These differences were depicted in our measurements: in 2013, the mDP values of the grape skins were higher than the corresponding values of the 2012 and 2014 samples, (especially those of the polymeric fractions) and were characterized by increased percentages of (-)-epicatechin units. Unlike grape skins, mDP values of grape seeds were not affected by vintage and their values were almost constant. Wine mDP values of 2013 were also increased compared to the relevant values of the other vintages; however, this increase was not as profound as that observed in grape skins, probably due to tannin modifications that occurred during vinification. Our results suggested that grape skin proanthocyanidin composition may be an indicator of grape tannin maturity. Among the skin proanthocyanidin constituents, it is suggested that (-)-epi-catechin content can be strongly influenced by the vintage year and its importance in wine quality should be further investigated.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Stamatina Kallithraka*, Ioannis Paraskevopoulos, Katerina Kanellopoulou, Sofoklis Petropoulos, Yorgos Kotseridis

*Agricultural University of Athens

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Effect of malolactic fermentation in barrels or stainless steel tanks on wine composition. Influence of the barrel toasting

Ellagitannin, anthocyanin and woody volatile composition of Cabernet Sauvignon wines aged in oak barrels for 12 months was evaluated. Depending on the container where malolactic fermentation (MLF) was carried out, two wine modalities were investigated: wines with MLF carried out in stainless steel tanks and barrel-fermented wines. Three toasting methods (medium toast, MT; medium toast with watering, MTAA; noisette) were considered for ageing of each wine modality. Sensory analyses (triangle and rating tests) were also performed. Two-way ANOVA of the raw experimental data revealed that the toasting method and the container where MLF took place, as well as the interaction between both factors, have a significant influence (p < 0.05) on ellagitannin, anthocyanin and woody volatile profiles of Cabernet Sauvignon wines.

Foam characteristics of white, rosé and red sparkling wines elaborated by the champenoise method

Contribution Foam is the characteristic that differentiates sparkling wines from still wines, being the first sensory attribute that tasters and consumers perceive and that determines the final quality of sparkling wines [1]. The foaming properties mainly depend on the chemical composition of wines [2-3], and different factors involved in wine composition will have an effect on foam quality. In Spain, the sparkling wine market focuses on the production of white and rosé sparkling wine, with very low production of red sparkling wines. However, this type of wines is elaborated in countries like Australia, South-Africa, Argentina, Italy or Portugal, with a great acceptance by consumers. No studies on the foaming characteristics of red sparkling wines have been found.

Monitoring of Pesticide Residues from Vine to Wine

Those previous years, pesticides are often brought to the forefront by media. Questions arose about their toxicity for growers and consumers. Even if a downward trend is underway, the use of pesticides is required to ensure steady quality and quantity of harvests. A large number of active ingredients are authorized but regarding viticulture, mainly insecticides and fungicides are applied, to control pests and diseases and to increase crop yield. Some phytosanitary products, principally fungicides, applied close to the harvest date may frequently be detected in wines.

Effects of a new vacuum evaporation method on chemical and sensory properties of must and wine

A new process for vacuum evaporation was developed where evaporation takes place near the inner surface of a vortex produced by a rotor submerged in the liquid. Contrary to the state of the art the Vortex rotor process does not need a vacuum vessel but the rotating liquid creates a geometrically stable low pressure void surrounded by a vortex stabilized by the equilibrium between centrifugal forces and the pressure difference. First tests with water and sugar solutions at concentrations similar to grape must were conducted to verify the theoretical predictions, test the performance under different conditions and study the effect of various process parameters (Rösti et al 2015).

On the losses of dissolved CO2 from laser-etched champagne glasses under standard tasting conditions

Under standard champagne tasting conditions, the complex interplay between the level of dissolved CO2 found in champagne, its temperature, the glass shape, and the bubbling rate, definitely impacts champagne tasting by modifying the neuro-physico-chemical mechanisms responsible for aroma release and flavor perception. Based on theoretical principles combining heterogeneous bubble nucleation, ascending bubble dynamics and mass transfer equations, a global model is proposed (depending on various parameters of both the wine and the glass itself), which quantitatively provides the progressive losses of dissolved CO2 from laser-etched champagne glasses.