terclim by ICS banner
IVES 9 IVES Conference Series 9 GRAPE SPIRITS FOR PORT WINE PRODUCTION: SCREENING THEIR AROMA PROFILE

GRAPE SPIRITS FOR PORT WINE PRODUCTION: SCREENING THEIR AROMA PROFILE

Abstract

Port is a fortified wine, produced from grapes grown in the demarcated Douro region. The fortification process consists in the addition of a grape spirit (77% v/v) to the fermenting juice for fermentation interruption, resulting in remaining residual sugars in the wine and increased alcohol content (19-22%). The approval of grape spirits follows the Appellation (D.O. Port wine) rules1 and it is currently carried out based on analytical control and on sensory evaluation done by the public Institute that upholds the control of the quality of Douro Appellation wines. However, the producers of Port wines would like to have more information about quality markers of grape spirits. Thus, this work intends to characterize the aroma profile of several samples (23) of grape spirits for Port wine production. That characterization was done by using aroma descriptive analysis with a sensory panel and by using olfactometry (GC-O) in order to screen, with a sniffers panel, the most potent odorant compounds across the several volatile compounds of the samples. It was also determined the sensory thresholds of some of the identified compounds in order to determine the odorant activity value of each compound.

The aroma profile results revealed different grape spirits aroma profiles. The PCA applied to the average results (from a sensory panel) of aroma attributes intensities allows the separation of the samples across the two principal components, which explain more than 50% of the variability. The overall quality appears to be linked to the positive side of component 1 more associated with the fruity, floral and sweet odor notes. The samples with low quality are placed in the opposite side of this component, and linked to higher intensity of odour notes such as tails, herbaceous and oily.

The chromatographic analysis (GC-O and GC-MS) of several grape spirit samples pointed out as potent odorants several compounds that belong to different chemical families, namely esters, alcohols, terpenic compounds, acids and ketones. Based on the sensory thresholds, determined by the sensory panel in hydroalcoholic solutions (20% v/v), the odorant activity values were calculated for the different odorant compounds. The obtained results showed, that the compounds, which presented the higher odorant activity values were esters and terpenic group compounds.

DOI:

Publication date: February 11, 2024

Issue: OENO Macrowine 2023

Type: Poster

Authors

Ilda Caldeira1,2, Sílvia Lourenço¹, Isabel Furtado³, Ricardo Silva³, Frank S. S. Rogerson³

1. Instituto Nacional de Investigação Agrária e Veterinária, Polo de Dois Portos, Quinta de Almoinha, 2565-191 Dois Portos, PORTUGAL
2. MED—Mediterranean Institute for Agriculture, Environment and Development Institute for Advanced Studies and Research, Universidade de Évora, Polo da Mitra, Ap. 94, 7006-554 Évora, PORTUGAL
3. Symington Family Estates, Vinhos S.A. Travessa Barão de Forrester, 86, 4400-034 Vila Nova de Gaia, PORTUGAL

Contact the author*

Keywords

Grape spirits, Port wine, odorant compounds, sensory analysis

Tags

IVES Conference Series | oeno macrowine 2023 | oeno-macrowine

Citation

Related articles…

HOW OXYGEN CONSUMPTION INFLUENCES RED WINES VOLTAMMETRIC PROFILE

Phenolic compounds play a central role in sensory characteristics of wine, such as colour, mouthfeel, flavour and determine its shelf life. Furthermore, the major non-enzymatic wine oxidation process is due to the catalytic oxidation of phenols in quinones. Due their importance, during the years have been developed different analytical methods to monitor the concentration of phenols in wine, such as Folin-Ciocalteu method, spectrophotometric techniques and HPLC. These methods can also be used to follow some oxidation-related chemical transformations.

HOLISTIC APPROXIMATION OF THE INFLUENCE OF SACCHAROMYCES STRAINS ON WINE AROMA PRECURSORS

Wine varietal aroma is the result of a mixture of compounds formed or liberated from specific grape-aroma precursors. Their liberation/formation from their specific precursors can occur spontaneously by acid catalyzed rearrangements or hydrolysis or by the action of the yeast enzymatic activities. The influence of yeast during fermentation on the production of these volatile compounds has been widely studied however, the effect of this influence during aging is not fully understood. In order to evaluate these processes several indirect strategies have been used to study aroma precursors although they are not useful to understand the chemistry of the process.

PHENOLICS DYNAMICS OF BERRIES FROM VITIS VINIFERA CV SYRAH GRAFTED ON TWO CONTRASTING ROOTSTOCKS UNDER COMBINED SALINITY AND WATER STRESSORS AND ITS EFFECT ON WINE QUALITY

Wine regions are getting warmer as average temperatures continue raising affecting grape growth, berry composition and wine production. Berry quality was evaluated in plants of Vitis vinifera cv Syrah grafted on two rootstocks, Paulsen (PL1103) and SO4, and grown under two salinity concentrations (LS:0.7dS/m and HS:2.5dSm-1) in combination with two irrigation regimes (HW:133% and CW:100%), being the seasonal water application 483mm (control, 100%). Spectrophotometer measurements from berry skin during veraison and harvest stages and from “young” wine samples, were indicative of the stressors effect and the mediation of the rootstocks. At veraison (i) total phenolics content were high under LSHW (0.7dSm-1 and high water conditions) for SO4 and PL1103.

SENSORY IMPROVEMENT OF DEALCOHOLISED WINES

Interest and willing-ness to buy alcohol-free wines by customers is increasing for several years [1]. Due to the rising relevance of dealcoholised wines it is the objective of this study to contribute to a better understanding of the flavor variation among dealcoholised wines and to explore enological measures, how to improve final quality.
First a range of commercial, alcoholfree white wines were analysed by the holistic sensory method projective mapping, including a question for hedonic acceptance. Based on the combination of a non-target-HS-SPME-GC/MS analysis with sensory analysis we obtained a clustering of the wines into three groups.

CHANGES IN CU FRACTIONS AND RIBOFLAVIN IN WHITE WINES DURING SHORT-TERM LIGHT EXPOSURE: IMPACTS OF OXYGEN AND BOTTLE COLOUR

Copper in white wine can be associated with Cu(II) organic acids (Cu fraction I), Cu(I) thiol species (Cu fraction II), and Cu sulfides (Cu fraction III). The first two fractions are associated with the repression of reductive aromas in white wine, but these fractions gradually decrease in concentration during the normal bottle aging of wine. Although exposure of white wine to fluorescent light is known to induce the accumulation of volatile sulfur compounds, causing light-struck aroma, the influence on the loss of protective Cu fractions is uncertain. Riboflavin is known to be a critical initiator of photochemical reac-tions in wine, but the rate of its decay under short-term light exposure in different coloured bottles and for wine of different oxygen concentrations is not well understood.