IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Unveiling the unknow aroma potential of Port wine fortification spirit taking advantage of the comprehensive two-dimensional gas chromatography

Unveiling the unknow aroma potential of Port wine fortification spirit taking advantage of the comprehensive two-dimensional gas chromatography

Abstract

Port wine is a fortified wine exclusively produced in the Douro Appellation (Portugal) under very specific conditions resulting from natural and human factors. Its intrinsic aroma characteristics are modulated upon a network of factors, such as the terroir, varieties and winemaking procedures that include a wide set of steps, namely the fortification with grape spirit (ca. 77% v/v ethanol). The fortification spirit comprises roughly one fifth of the total volume of this fortified wine, thus it is a potential contributor to the global quality of this beverage, including the aroma notes. Nonetheless, the information about the influence of the fortification spirit on the final aroma of Port wine, as well as the grape spirit volatile composition are extremely limited. Therefore, the main objective of this research is the optimization of an adequate methodology for the in-depth characterization of the fortification grape spirit volatile components, based on the use of advanced gas chromatography (GC×GC-ToFMS), combined with a solvent free solid phase microextraction technique (SPME). To fulfil this objective, the SPME experimental parameters (fiber coating, extraction temperature, and time, sample volume and dilution conditions) were optimized. Also, different column sets (first × second dimensions) were also tested to obtain the best chromatographic resolution and peak capacity. Firstly, the GC×GC-ToFMS experimental parameters were implemented, and the reversed phase column set (polar 1D × nonpolar 2D), with the same diameters in primary and secondary columns, presented advantages compared to the conventional column set (nonpolar 1D × polar 2D) regarding the analytes´ separation. Secondly, the SPME conditions that promoted the highest extraction efficiency were selected: 2.0 mL of spirit (diluted at 10% v/v ethanol) were extract with poly(dimethylsiloxane)/divinylbenzene fiber, at 40˚C, using 10 min of pre-equilibrium followed by 30 min of extraction. An exploratory application was performed using a set of grape spirits, which allowed the detection of hundreds of volatiles, from which 120 were putatively identified. This study adds further insights unveiling the complex nature of the grape spirits chemical volatile data, through the identification of compounds not yet determined in these matrices, some of which are associated with aroma notes highly valued in fortified wines. In addition, these volatile patterns seem to be useful to the spirits distinction/typing.

Acknowledgments:

This work was funded under the AD4PurePort – New range of Port wines, based on an innovative method of selecting fortification spirits), project 39956 – POCI-01-0247-FEDER-039956, supported by the COMPETE 2020 Operational Programme under the PORTUGAL 2020. Thanks are also due to FCT/MEC for the financial support LAQV-REQUIMTE (UIDB/50006/2020) through national funds and co-financed by the FEDER, with a PT2020 Partnership Agreement.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Poster

Authors

Rocha Silvia1, Tavares Tiago1, Ribeiro Sónja1, Furtado Isabel2, Silva Ricardo2, Rogerson Frank S. S.2, Rudnitskaya Alisa3

1LAQV-REQUIMTE & Department of Chemistry, University of Aveiro
2Symington Family Estates
3CESAM & Department of Chemistry &, University of Aveiro

Contact the author

Keywords

Fortification spirit, Port wine, Volatile organic components, HS-SPME, GC×GC-ToFMS

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Influence of a spontaneous cover crop on the vineyard and soil erosion under Mediterranean climate

Sixty five % of the agricultural area of the Basque Country located in the DO Ca Rioja corresponds to vineyards. More than 40% of it has an average slope greater than 10%, which makes it sensitive to erosive processes. Furthermore, it is foreseeable that extreme weather events (storms, hail, extreme heat and cold, etc.) will be favored due to climate change. Cover cropping can mitigate this risk, and therefore the objective of this work is to evaluate the impact that a vegetable cover has on the agronomic behavior of the vineyard, the quality of the grape and soil erosion. For this, a trial has been carried out with a Graciano variety vineyard with a slope between 10% -20% during the years 2020 and 2021. Conventional tillage management in the area has been compared (4-6 passes per year of tillage machinery) versus spontaneous vegetation cover management in the vineyard. This implies not tilling and allowing the grass of the land to colonize the range between the lines of vines, controlling their height through 1-3 mowing passes per year, always trying to affect the surface of the land as little as possible. The vegetative growth, yield and quality of the grape and wine was measured. Furthermore, erosion has been measured using Gerlasch boxes. The yield was lower in the second year of the trial in the cover crop treatment, but erosion was significantly reduced.

Geospatial trends of bioclimatic indexes in the topographically complex region of Barolo DOCG

Barolo DOCG is an economically important wine producing region in Northwest Italy. It is a small region of approximately 70 km2 gross area. The topography is very complex with steep sloped hills ranging in elevation from below 200 m to 550 m. Barolo DOCG wine is made exclusively from the Nebbiolo grape. Bioclimatic indexes are often used in viticulture to gain a better understanding of broader climate trends which can be compared temporally and geographically. These indexes are also used for identifying potential phenological timing, growing region suitability, and potential risks associated with expected climatic changes. Understanding how topography influences bioclimatic indexes can help with understanding of mesoscale climate behaviour leading to improved decision making and risk management strategies. The average monthly maximum and minimum temperatures, the Cool Night Index, the Huglin Index, and the monthly diurnal range (from July to October) were calculated using data from 45 weather stations within a 40 km radius of the Barolo DOCG growing area between the years 1996 and 2019. Linear and multiple regression models were developed using independent variables (elevation, aspect, slope) extracted from a digital elevation model to identify significant relationships. Bioclimatic indexes were then kriged with external drift using independent variables that showed significant relationships with the bioclimatic index using a 100 m resolution grid. The maximum monthly temperatures and the Huglin Index showed consistent significant negative relationships with elevation in all years. The minimum monthly temperatures showed no relationship with elevation but in some months a small but significant relationship was observed with aspect. Due to the lack of a relationship between minimum monthly temperatures and elevation compared to the significant relationship between maximum monthly temperatures and elevation, monthly diurnal range had a negative relationship with elevation.

The impact of sustainable management regimes on amino acid profiles in grape juice, grape skin flavonoids, and hydroxycinnamic acids

One of the biggest challenges of agriculture today is maintaining food safety and food quality while providing ecosystem services such as biodiversity conservation, pest and disease control, ensuring water quality and supply, and climate regulation. Organic farming was shown to promote biodiversity and carbon sequestration, and is therefore seen as one possibility of environmentally friendly production. Consumers expect organically grown crops to be free from chemical pesticides and mineral fertilizers and often presume that the quality of organically grown crops is different or higher compared to conventionally grown crops. Integrated, organic, and biodynamic viticulture were compared in a replicated field trial in Geisenheim, Germany (Vitis vinifera L. cv. Riesling). Amino acid profiles in juice, grape skin flavonoids, and hydroxycinnamic acids were monitored over three consecutive seasons beginning 7 years after conversion to organic and biodynamic viticulture, respectively. In addition, parameters such as soil nutrient status, yield, vigor, canopy temperature, and water stress were monitored to draw conclusions on reasons for the observed changes. Results revealed that the different sustainable management regimes highly differed in their amino acid profiles in juice and also in their skin flavonol content, whereas differences in the flavanol and hydroxycinnamic acid content were less pronounced. It is very likely that differences in nutrient status and yield determined amino acid profiles in juice, although all three systems showed similar amounts of mineralized nitrogen in the soil. Canopy structure and temperature in the bunch zone did not differ among treatments and therefore cannot account for the observed differences in favonols. A different light exposure of the bunches in the respective systems due to differences in vigor together with differences in berry size and a different water status of the vines might rather be responsible for the increase in flavonol content under organic and biodynamic viticulture.

Under-vine management effects on grapevine production, soil properties and plant communities in South Australia

Under-vine (UV) management has traditionally consisted of synthetic herbicide use to limit competition between weeds and grapevines. With growing global interest towards non-synthetic chemical use, this study aimed to capture the effects of alternative UV management at two commercial Shiraz vineyards in South Australia, where the sole management variables were UV management since 2016. In adjacent treatment blocks, cultivation (CU) was compared to spontaneous vegetation (SV) in McLaren Vale (MV), and herbicide was compared to SV in Eden Valley (EV). Soil water infiltration rates were slower and grapevine stem water potential was lower in CU compared to SV in MV, with the latter having a plant community dominated by soursob (Oxalis pes-caprae) during winter; while in EV, there was little separation between the treatments. Yields were affected at both sites, with SV being higher in MV and HE being higher in EV. In MV, the only effect on grape must was a lower 13C:12C isotope ratio in CU, indicating greater grapevine water stress. In the grape must at EV, SV had higher total soluble solids, total phenolics, anthocyanins, and yeast available nitrogen; and lower pH and titratable acidity. Pruning weights were not affected by the treatments in MV, while they were higher in HE at EV. Assessments revealed that the differing soil types at the two sites were likely the main determinants of the opposing production outcomes associated with UV management. In the silty loam soil of MV, the higher yields in SV were likely due to more plant-available water, as a potential result of the continuous soil bio-pores formed by winter UV vegetation. Conversely, in the loamy sand soils of EV with a lower cation exchange capacity, the lower yields and pruning weights in SV suggest the UV vegetation competed significantly with the grapevines for available water and nutrients.

Elevational range shifts of mountain vineyards: Recent dynamics in response to a warming climate

Increasing temperatures worldwide are expected to cause a change in spatial distribution of plant species along elevational gradients and there are already observable shifts to higher elevations as a consequence of climate change for many species. Not only naturally growing plants, but also agricultural cultivations are subject to the effects of climate change, as the type of cultivation and the economic viability depends largely on the prevailing climatic conditions. A shift to higher elevations therefore represents a viable adaptation strategy to climate change, as higher elevations are characterized by lower temperatures. This is especially important in the case of viticulture because a certain wine-style can only be achieved under very specific climatic conditions. Although there are several studies investigating climatic suitability within winegrowing regions or longitudinal shifts of winegrowing areas, little is known about how fast vineyards move to higher elevations, which may represent a viable strategy for winegrowers to maintain growing conditions and thus wine-style, despite the effects of climate change. We therefore investigated the change in the spatial distribution of vineyards along an elevational gradient over the past 20 years in the mountainous wine-growing region of Alto Adige (Italy). A dataset containing information about location and planting year of more than 26000 vineyard parcels and 30 varieties was used to perform this analysis. Preliminary results suggest that there has been a shift to higher elevations for vineyards in general (from formerly 700m to currently 850 m a.s.l., with extreme sites reaching 1200 m a.s.l.), but also that this development has not been uniform across different varieties and products (i.e. vitis vinifera vs hybrid varieties and still vssparkling wines). This is important for climate change adaptation as well as for rural development. Mountain areas, especially at mid to high elevations, are often characterized by severe land abandonment which can be avoided to some degree if economically viable and sustainable land management strategies are available.