IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Using 1H-NMR combined with chemometrics to discriminate the effect of different cuts and toasting of woods used for grape pomace distillate ageing

Using 1H-NMR combined with chemometrics to discriminate the effect of different cuts and toasting of woods used for grape pomace distillate ageing

Abstract

The purpose of this research study is to consider new solutions for distillate ageing, in alternative to conventional oak chips or barrels in particular sliced wood and peeled wood were compared to oak cubes, normally employed during both wine and distillate ageing. All three formats have been toasted using a “in lab” protocol at three different level of intensity: strongly toasted, lightly toasted and not toasted.
NMR spectroscopy was used to assess the differences, in and the chemical fingerprint among experimental distillates, aged using woods with different cuts and toasting levels.
NMR spectrometry is widely used in food analysis for metabolomic studies and for the evaluation of samples that have undergone different treatments. NMR allows to obtain a complex fingerprint spectrum characterised by the chemical species of the samples. The advantages of high resolution 1H-NMR are absolute reproducibility and laboratory-to-laboratory transferability, compared to other method currently used in food analysis. The region between 11 and 6 ppm of 1H-NMR spectra was chosen focussing on the range where main structural differences related to xylovolatile compounds, namely phenols, aldehydes and aromatic groups were present.
The obtained 1H-NMR data sets were firstly analysed by chemometric multivariate unsupervised methods, that showed a good separation between the control sample (i.e. distillates aged without oak) and all other samples, as well as between the different sample groups. In particular, principal components analysis (PCA), Anova-Simultaneous components analysis (ASCA) and hierarchical cluster analysis (HCA) were calculated and compared. This approach showed that samples refined with strongly, lightly or not toasted wood present a different molecular profile. A group separation was observed based on the wood cut type (i.e. sliced, peeled or cubes). Moreover, a non-negligible effect of the interaction between cut type and the toasting level was noticed.
Hence, the results confirmed the ageing process, that affects the chemical profile of grape pomace distillates, can be effectively monitored by NMR analysis. This provides a promising tool for distinguishing the different ageing conditions of spirits and assessing their quality

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Portesi Chiara1, Mandrile Luisa1, Asproudi Andriani2, Bonello Federica2, Chiarabaglio Pier Mario3, Rosso Laura3 and Petrozziello Maurizio2

1INRiM – Istituto Nazionale di Ricerca Metrologica, Politecnico di Torino
2CREA, Research Centre for Viticulture and Enology
3CREA – Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Centro di Ricerca Foresta e Legno 

Contact the author

Keywords

Toasting process, wood chips, NMR, grape pomace distillate, chemometrics

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Influence of weather and climatic conditions on the viticultural production in Croatia

The research includes an analysis of the impact of weather conditions on phenological development of the vine and grape quality, through monitoring of four experimental cultivars (Chardonnay, Graševina, Merlot and Plavac mali) over two production years. In each experimental vineyard, which were evenly distributed throughout the regions of Slavonia and The Croatian Danube, Croatian Uplands,

Variations of soil attributes in vineyards influence their reflectance spectra

Knowledge on the reflectance spectrum of soil is potentially useful since it carries information on soil chemical composition that can be used to the planning of agricultural practices. If compared with analytical methods such as conventional chemical analysis, reflectance measurement provides non-destructive, economic, near real-time data. This paper reports results from reflectance measurements performed by spectroradiometry on soils from two vineyards in south Brazil. The vineyards are close to each other, are on different geological formations, but were subjected to the same management. The objective was to detect spectral differences between the two areas, correlating these differences to variations in their chemical composition, to assess the technique’s potential to predict soil attributes from reflectance data.To that end, soil samples were collected from ten selected vine parcels. Chemical analysis yield data on concentration of twenty-one soil attributes, and spectroradiometry was performed on samples. Chemical differences significant to a 95% confidence level between the two studied areas were found for six soil attributes, and the average reflectance spectra were separated by this same level along most of the observed spectral domain. Correlations between soil reflectance and concentrations of soil attributes were looked for, and for ten soil traits it was possible to define wavelength domains were reflectance and concentrations are correlated to confidence levels from 95% to 99%. Partial Least Squares Regression (PLSR) analyses were performed comparing measured and predicted concentrations, and for fifteen out of 21 soil traits we found Pearson correlation coefficients r > 0.8. These preliminary results, which have to be validated, suggest that variations of concentration in the investigated soil attributes induce differences in reflectance that can be detected by spectroradiometry. Applications of these observations include the assessment of the chemical content of soils by spectroradiometry as a fast, low-cost alternative to chemical analytical methods.

Anthocyanin profile is differentially affected by high temperature, elevated CO2 and water deficit in Tempranillo (Vitis vinifera L.) clones

Anthocyanin potential of grape berries is an important quality factor in wine production. Anthocyanin concentration and profile differ among varieties but it also depends on the environmental conditions, which are expected to be greatly modified by climate change in the future. These modifications may significantly modify the biochemical composition of berries at harvest, and thus wine typicity. Among the diverse approaches proposed to reduce the potential negative effects that climate change may have on grape quality, genetic diversity among clones can represent a source of potential candidates to select better adapted plant material for future climatic conditions. The effects of individual and combined factors associated to climate change (increase of temperature, rise of air CO2 concentration and water deficit) on the anthocyanin profile of different clones of Tempranillo that differ in the length of their reproductive cycle were studied. The aim was to highlight those clones more adapted to maintain specific Tempranillo typicity in the future. Fruit-bearing cuttings were grown in controlled conditions under two temperatures (ambient temperature versus ambient temperature + 4ºC), two CO2 levels (400 ppm versus 700 ppm) and two water regimes (well-watered versus water deficit), both in combination or independently, in order to simulate future climate change scenarios. Elevated temperature increased anthocyanin acylation, whereas elevated CO2 and water deficit favoured the accumulation of malvidin derivatives, as well as the acylation and tri-hydroxylation level of anthocyanins. Although the changes in anthocyanin profile observed followed a common pattern among clones, such impact of environmental conditions was especially noticeable in one of the most widely distributed Tempranillo clones, the accession RJ43.

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.

The plantation frame as a measure of adaptation to climate change

The mechanization of vineyard work originally led to a reduction in planting densities due to the lack of machinery adapted to the vineyard. The current availability of specific machinery makes it possible to establish higher planting densities. In this work, three planting densities (1.40×0.80 m, 1.80×1 m and 2.20×1.20 m, corresponding to 8928, 5555 and 3787 plants/ha respectively) were studied with four varieties autochthonous of Galicia (northwestern Spain): Albariño and Treixadura (white), Sousón and Mencía (red). The vines were trained in a vertical shoot positioning system using a single Royat cordon, and pruned to spurs with two buds each. Agronomic data (yield, pruning wood weight, Ravaz index) and oenological data in must were collected. The higher planting density (1.40×0.80 m) had no significant effect on grape yield per vine in white varieties, although production per hectare was much higher due to the greater number of plants. In red varieties, this planting density resulted in a significantly lower production per vine, compensated by the greater number of plants. In addition, it significantly reduced the Brix degree in the must of the Albariño, Treixadura and Sousón varieties, and increased the total acidity in the latter two and Mencía. It also caused an increase in extractable and total anthocyanins and IPT in red grapes. The effects of high planting density on grapes are of great interest for the adaptation of varieties in the context of climate change. In the future, it could be advisable to modify the limits imposed by the appellations of origin on the planting density of these varieties in order to obtain more balanced wines.