Macrowine 2021
IVES 9 IVES Conference Series 9 Phenolic and volatile profiles of south tyrolean pinot blanc musts and young wines

Phenolic and volatile profiles of south tyrolean pinot blanc musts and young wines

Abstract

AIM. Assess the impact of different vineyards and winemaking variables on the phenolic and volatile profiles of Pinot Blanc musts and young wines from South Tyrol.

METHODS. Grapes were harvested during September 2019 in 3 vineyards near Ora (Italy) at 450 m (MM), 550 m (K) and 800 m (V) a.s.l. Six different types of Pinot Blanc musts and young wines were studied in 3 replicates. Study A – 3 different vineyards (MM_C, K_C, V_C), but same winemaking; Study B – same vineyard (V), but 3 different vinifications: i) grapes were frozen before crushing (V_F); ii) same as V_F, but co-inoculation yeast/malolactic bacteria (V_F_ML); iii) no grape freezing, but co-inoculation yeast/malolactic bacteria (V_ML). Phenolics were analysed by HPLC-DAD and HPLC-QqQ-MS, while volatiles were investigated by SPME-HS-GCxGC-ToF-MS. Standard oenological parameters were measured using a multi-parametric analyser, alcohol distillation, pH-meter and chemical titration. The data were statistically processed with ANOVA and Principal Component Analysis (PCA).

RESULTS. Upon a dataset of 27 phenolic compounds identified in musts, a good separation among samples was achieved using PCA. The musts produced without pre-fermentative grape freezing had significantly higher amounts of catechin, gallocatechin and astilbin. Besides, the musts from the same vineyard, but with frozen grapes showed higher concentrations of ethanol, glucose-fructose, malic acid, and lower concentration of tartaric acid. 46 phenolic compounds were identified in wines. The PCA separated well the samples of Study A: caftaric acid showed the most significant difference as well as the highest relative abundance. The PCA showed that the phenolic profile of the wines of Study B (V_C, V_F, V_F_ML, V_ML) clustered samples based on the pre-fermentative grape freezing. Wines made without frozen grapes were separated due to the higher phenolic concentrations. The volatile profile of wines after 1 month of storage contained 32 compounds. The PCA not only grouped samples according to the grape freezing, but it also showed that wines with no applied grape freezing were well clustered in terms of the presence/absence of malolactic fermentation in their winemaking. V_C samples were described by higher abundances of branched chain alcohols, while samples V_ML – by ethyl and phenylethyl esters.

CONCLUSIONS

The profiles of phenolics and volatiles were good discriminants of South Tyrolean Pinot Blanc wines produced under the same winemaking technology but harvested in different vineyards. In this study, the pre-fermentative grape freezing negatively affected concentrations of phenolics. The literature shows that freezing positively enhances contents only of anthocyanins and flavanol glucosides, while it negatively affects contents of phenolic acids and flavanols, that are main phenolic compound in white wines.

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Vakare Merkyte

1. Free University of Bozen-Bolzano, Faculty of Science and Technology, Piazza Università 5, 39100 Bozen-Bolzano, Italy; 2. Oenolab, NOI Techpark South Tyrol, Via A. Volta 13B, 39100 Bozen-Bolzano, Italy,Simone POGGESI, 1. Free University of Bozen-Bolzano, Faculty of Science and Technology, Piazza Università 5, 39100 Bozen-Bolzano, Italy; 2. Oenolab, NOI Techpark South Tyrol, Via A. Volta 13B, 39100 Bozen-Bolzano, Italy Edoardo LONGO, 1. Free University of Bozen-Bolzano, Faculty of Science and Technology, Piazza Università 5, 39100 Bozen-Bolzano, Italy; 2. Oenolab, NOI Techpark South Tyrol, Via A. Volta 13B, 39100 Bozen-Bolzano, Italy Fabian STENICO, 1. Free University of Bozen-Bolzano, Faculty of Science and Technology, Piazza Università 5, 39100 Bozen-Bolzano, Italy; 2. Oenolab, NOI Techpark South Tyrol, Via A. Volta 13B, 39100 Bozen-Bolzano, Italy Giulia WINDISCH, 1. Free University of Bozen-Bolzano, Faculty of Science and Technology, Piazza Università 5, 39100 Bozen-Bolzano, Italy; 2. Oenolab, NOI Techpark South Tyrol, Via A. Volta 13B, 39100 Bozen-Bolzano, Italy Emanuele BOSELLI, 1. Free University of Bozen-Bolzano, Faculty of Science and Technology, Piazza Università 5, 39100 Bozen-Bolzano, Italy; 2. Oenolab, NOI Techpark South Tyrol, Via A. Volta 13B, 39100 Bozen-Bolzano, Italy

Contact the author

Keywords

pinot blanc; white wine; phenolic profile; volatile profile; grape freezing; malolactic fermentation; chemical markers; vinification practices

Citation

Related articles…

Drought effect on aromatic and phenolic potential of seven recovered grapevine varieties in Castilla-La Mancha region (Spain)

The effects of climate change are seriously affecting the quality of wine grapes. High temperatures and drought cause imbalances in the chemical composition of grapes. The result is overripe grapes with low acidity and high sugar content, which produce wines with excessive alcohol content, lacking in freshness and not very aromatic. As a consequence, the search of varieties with capacity of produce quality grapes in adverse climate conditions is a good alternative to preserve the sustainability of vineyards. In this work, quality parameters of seven Vitis vinifera L. cultivars (five whites and two reds) recently recovered from extinction and grown under two different hydric regimes (rainfed and irrigated) were analyzed during the 2020 vintage. At harvest time, weight of 100 berries, must physicochemical parameters (brix degree, total acidity, malic acid, pH), and carbon and oxygen isotope ratios (δ13C, δ18O) were determined. Subsequently, varietal aroma potential index (IPAv) and total polyphenol index (TPI) were analyzed. Quality parameters, IPAv and TPI, showed significant differences between varieties and water regimes. Both red varieties, Moribel and Tinto Fragoso, stood out for their high aromatic and phenolic potential, which was higher under rainfed regime. Regarding to white varieties, Montonera del Casar and Jarrosuelto stood out in terms of varietal aroma potential. Montonera del Casar high acidity in its musts and Jarrosuelto showed the highest berry weights.

A blueprint for managing vine physiological balance at different spatial and temporal scales in Champagne

In Champagne, the vine adaptation to different climatic and technical changes during these last 20 years can be seen through physiological balance disruptions. These disruptions emphasize the general grapevine decline. Since the 2000s, among other nitrogen stress indicators, the must nitrogen has been decreasing. The combination of restricted mineral fertilizers and herbicide use, the growing variability of spring rainfall, the increasing thermal stress as well as the soil type heterogeneity are only a few underlying factors that trigger loss of physiological balance in the vineyards. It is important to weigh and quantify the impact of these factors on the vine. In order to do so, the Comité Champagne uses two key-tools: networking and modelization. The use of quantitative and harmonized ecophysiological indicators is necessary, especially in large spatial scales such as the Champagne appellation. A working group with different professional structures of Champagne has been launched by the Comité Champagne in order to create a common ecophysiology protocol and thus monitor the vine physiology, yearly, around 100 plots, with various cultural practices and types of soil. The use of crop modelling to follow the vine physiological balance within different pedoclimatic conditions enables to understand the present balance but also predict the possible disruptions to come in future climatic scenarios. The physiological references created each year through the working group, benefit the calibration of the STICS model used in Champagne. In return, the model delivers ecophysiology indicators, on a daily scale and can be used on very different types of soils. This study will present the bottom-up method used to give accurate information on the impacts of soil, climate and cultural practices on vine physiology.

20-Year-Old data set: scion x rootstock x climate, relationships. Effects on phenology and sugar dynamics

Global warming is one of the biggest environmental, social, and economic threats. In the Douro Valley, change to the climate are expected in the coming years, namely an increase in average temperature and a decrease in annual precipitation. Since vine cultivation is extremely vulnerable and influenced by the climate, these changes are likely to have negative effects on the production and quality of wine.
Adaptation is a major challenge facing the viticulture sector where the choice of plant material plays an important role, particularly the rootstock as it is a driver for adaptation with a wide range of effects, the most important being phylloxera, nematode and salt, tolerance to drought and a complex set of interactions in the grafted plant.
In an experimental vineyard, established in the Douro Region in 1997, with four randomized blocs, with five varieties, Touriga Nacional, Tinta Barroca, Touriga Franca and Tinta Roriz, grafted in four rootstocks, Rupestris du Lot, R110, 196-17C, R99 and 1103P, data was collected consecutively over 20 years (2001-2020). Phenological observations were made two to three times a week, following established criteria, to determine the average dates of budbreak, flowering and veraison. During maturation, weekly berry samples were taken to study the dynamics of sugar accumulation, amongst other parameters. Climate data was collected from a weather station located near the vineyard parcel, with data classified through several climatic indices.
The results achieved show a very low coefficient of variations in the average date of the phenophases and an important contribution from the rootstock in the dynamic of the phenology, allowing a delay in the cycle of up to10-12 days for the different combinations. The Principal Component Analysis performed, evaluating trends in the physical-chemical parameters, highlighted the effect of the climate and rootstock on fruit quality by grape varieties.

Projected changes in vine phenology of two varieties with different thermal requirements cultivated in La Mancha DO (Spain) under climate change scenarios

The aim of this work was to analyze the phenology variability of Tempranillo and Chardonnay cultivars, related to the climatic characteristics in La Mancha Designation of Origin, and their potential changes under climate change scenarios. Phenological dates referred to budbreak, flowering, veraison and harvest were analyzed for the period 2000-2019. The weather conditions at daily time scale, recorded during the same period, were also evaluated. The thermal requirements to reach each of these phenological stages were calculated and expressed as the GDD accumulated from DOY=60. Changes in phenology were projected by 2050 and 2070 taking into account those values and the projected temperatures and precipitation, simulated under two Representative Concentration Pathway (RCP) scenarios –RCP4.5 and RCP8.5– using an ensemble of models. The average phenological dates during the period under study were, April 16th ± 6.6 days and April 5th ± 6.0 days for budbreak, May 31st ± 6.0 days and May 27th ± 5.3 days for flowering, July 26th ± 5.6 days and July 25th ± 5.8 days for veraison, and Ago 23rd ± 10.8 days and Ago 17th ± 9.0 days for harvest, respectively, for Tempranillo and Chardonnay. The projected changes in temperature imply an average change in the maximum growing season (April-August) temperatures of 1.2 and 1.9°C by 2050, and 1.6 and 2.6°C by 2070, under the RCP4.5 and RCP8.5 scenarios, respectively. A reduction in precipitation is predicted, which vary between 15% for 2050 under RCP4.5 scenario and up to 30% by 2070 under RCP8.5. The advance of the phenological dates for 2050, could be of 6, 7, 7, and 8 days for Tempranillo and 4, 6, 6 and 9 days for Chardonnay, respectively for budbreak, flowering, veraison and harvest under the RCP4.5 scenario. Under the RCP8.5 emission scenario, the advance could be up to 30% higher.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.