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…

Adaptability of grapevines to climate change: characterization of phenology and sugar accumulation of 50 varieties, under hot climate conditions

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

Assessing the climate change vulnerability of European winegrowing regions by combining exposure, sensitivity and adaptive capacity indicators

Winegrowing regions recognized as protected designations of origin (PDOs) are closely tied to well defined geographic locations with a specific set of pedoclimatic attributes and strictly regulated by legal specifications. However, climate change is increasingly threatening these regions by changing local conditions and altering winegrowing processes. The vulnerability to these changes is largely heterogenous across different winegrowing regions because it is determined by individual characteristics of each region, including the capacity to adapt to new climatic conditions and the sensitivity to climate change, which depend not only on natural, but also socioeconomic and legal factors. Accurate vulnerability assessments therefore need to combine information about adaptive capacity and climate change sensitivity with projected exposure to new climatic conditions. However, most existing studies focus on specific impacts neglecting important interactions between the different factors that determine climate change vulnerability. Here, we present the first comprehensive vulnerability assessment of European wine PDOs that spatially combines multiple indicators of adaptive capacity and climate change sensitivity with high-resolution climate projections. We found that the climate change vulnerability of PDO areas largely depends on the complex interactions between physical and socioeconomic factors. Homogenous topographic conditions and a narrow varietal spectrum increase climate change vulnerability, while the skills and education of farmers, together with a good economic situation, decrease their vulnerability. Assessments of climate change consequences therefore need to consider multiple variables as well as their interrelations to provide a comprehensive understanding of the expected impacts of climate change on European PDOs. Our results provide the first vulnerability assessment for European winegrowing regions at high spatiotemporal resolution that includes multiple factors related to climate exposure, sensitivity, and adaptive capacity on the level of single winegrowing regions. They will therefore help to identify hot spots of climate change vulnerability among European PDOs and efficiently direct adaptation strategies.

Ecophysiological performance of Vitis rootstocks under water stress

The use of rootstocks tolerant to soil water deficit is an interesting strategy to cope with limited water availability. Currently, several nurseries are breeding new genotypes, but the physiological basis of its responses under water stress are largely unknown. To this end, an ecophysiological assessment of the conventional 110-Richter (110R) and SO4, and the new M1 and M4 rootstocks was carried out in potted ungrafted plants. During one season, these Vitis genotypes were grown under greenhouse conditions and subjected to two water regimes, well-watered and water deficit. Water potentials of plants under water deficit down to < -1.4 MPa, and net photosynthesis (AN) <5 μmol m-2 s-1 did not cause leaf oxidative stress damage compared to well-watered conditions in any of the genotypes. The antioxidant capacity was sufficient to neutralize the mild oxidative stress suffered. Under both treatments, gravimetric differences in daily water use were observed among genotypes, leading to differences in the biomass of root, shoot and leaf. Under well-watered conditions, SO4 and 110R were the most vigorous and M1 and M4 the least. However, under water stress, SO4 exhibited the greatest reduction in biomass while M4 showed the lowest. Remarkably, under these conditions, SO4 reached the least negative stem water potential (Ψstem), while M1 reduced stomatal conductance (gs) and AN the most. In addition, SO4 and M1 genotypes also showed the highest and lowest hydraulic conductance values, respectively. Our results suggest that there are differences in water use regulation among genotypes, not only attributed to differences in stomatal regulation or intrinsic water use efficiency at the leaf level. Therefore, because no differences in canopy-to-root ratio were achieved, it is hypothesized that xylem vessel anatomical differences may be driving the reported differences among rootstocks performance. Results demonstrate that each Vitis rootstock differs in its ecophysiological responses under water stress.

Bioclimatic shifts and land use options for Viticulture in Portugal

Land use, plays a relevant role in the climatic system. It endows means for agriculture practices thus contributing to the food supply. Since climate and land are closely intertwined through multiple interface processes, climate change may lead to significant impacts in land use. In this study, 1-km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS)