Tesi etd-03102025-190737
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Tipo di tesi
Dottorato
Autore
LITTARRU, ELEONORA
URN
etd-03102025-190737
Titolo
The impact of canopy management and environmental factors on aromatic and phenol compound profiles of Sangiovese and Moscato Bianco grapes and wines
Settore scientifico disciplinare
AGR/03
Corso di studi
Istituto di Scienze della Vita - PHD IN AGROBIOSCIENZE
Commissione
relatore Prof. TONUTTI, PIETRO
Parole chiave
- Nessuna parola chiave trovata
Data inizio appello
10/07/2025;
Disponibilità
completa
Riassunto analitico
The grapevine (Vitis vinifera) is one of the most economically and culturally significant fruit crops worldwide, with global wine production reaching 237 million hectolitres in 2023 and an export value of approximately 36 billion euros. Wine quality is intrinsically linked to berry composition, which is shaped by genetic diversity, environmental conditions and viticultural practices. These factors are all encompassed within the concept of terroir, which ties the typicity of a wine to the unique characteristics of its growing environment. However, the wine industry is currently facing unprecedented challenges. Over the past 50 years, climate change has significantly altered grapevine development, advancing the harvest date by nearly one month. This shift is disrupting traditional growing conditions, accelerating sugar accumulation, delaying phenolic ripening, and altering aroma profiles. Coupled with evolving consumer preferences for lighter wines with moderate alcohol content, distinct and recognizable traits of the grapes variety/ies, sustainable production practices, all these changes need a combination of adaptation and mitigation strategies to adapt viticulture and winemaking to a rapidly changing environment and market. A range of traditional and innovative approaches, both short- and long -term, can be employed, including selecting appropriate varieties, clones and rootstocks, exploring new growing regions, and diversifying wine production, also through a better characterization of the grapes (and the resulting wines) produced within a defined macro-area, or even within the same wine farm. A better knowledge of the impact of natural resources (e.g. soil type, vineyard slope exposure) in a specific grape growing area is essential to optimize agronomical practices, in particular, harvest time to produce in highly vocated areas, top quality/cru wines. Considering agronomical practices, in addition to soil management and, if applied, irrigation strategies, canopy management represents an important factor modulating grape composition and quality at harvest. This is the case of practices such as leaf removal and cluster thinning which, by changing the leaf/fruit ratio and the microclimate around grape clusters may affect berry development and ripening-related processes .
The accurate monitoring of berry ripening is a crucial step for top quality viticulture and wine making. Non-destructive analytical techniques (NDAT) tools, such as NIR spectroscopy and e-nose systems, may enable rapid, real-time assessment of grape composition, supporting decisions on harvest timing and winemaking strategies. Their future integration into traditional practices depends on the development of specific and targeted devices, that must be optimized for these purposes and application.
These topics have been addressed in the present dissertation which specifically reports results regarding: (1) the effects of canopy management protocols (basal leaf removal, cluster thinning) on aroma compounds, particularly monoterpenes, in Moscato Bianco grapes; (2) the impact of different soils and vineyard slope exposures on Sangiovese grapes and wines in the Chianti Classico area, and (3) the integration of advanced monitoring technologies to optimize the vinification processes.
The first addresses the issue of the decline in monoterpenes, key aroma compounds in Moscato Bianco grapes and wines, as observed by winemakers and viticulturists in the Asti DOCG area of Piedmont. To tackle this issue, the impact of canopy management techniques -specifically basal leaf removal at veraison and at post-berry set and cluster thinning at veraison- on the accumulation of monoterpenes was investigated. Conducted over two growing seasons in two distinct vineyards at different altitudes within the Asti DOCG region, this research highlights the importance of microclimatic modifications in shaping grape composition and preserving the aromatic quality of Moscato d’Asti and Asti Spumante wines. In the vineyard located at lower altitude, leaf removal at veraison (VER) and cluster thinning (THIN) significantly enhanced the accumulation of monoterpenes particularly at the time T2 (corresponding to the commercial harvest for Moscato d’Asti wine production). Conversely, in the higher-altitude vineyard, the effects of the treatments were less pronounced at the timeT1 (harvest for Asti Spumante) and showed limited benefits at T2, highlighting the importance of site-specific management of the applied protocols. These findings underscore the role of microclimatic conditions, such as light exposure and thermal variability, in shaping aroma compound accumulation and the need for tailored viticultural practices to achieve desired aromatic profiles.
The second reports data, collected in two consecutive years on the influence of soil type and vineyard slope exposure on Sangiovese grapes grown in the same wine farm located in the Chianti Classico area. Three different types of soil were taken into consideration, one predominantly sandy and two predominantly clayey, corresponding to three distinct Sangiovese cru (FZ7, M17, ML6), having the same clone (R24) and the same rootstock (1103P), with south and north slope exposure, respectively. Transcriptomic analysis and metabolomic profiles were monitored weekly at three time points prior to the harvest date. Clay-rich soils were associated with higher concentrations of tri-substituted anthocyanins, such as malvidin derivatives, which contribute to color stability. In contrast, sandy soils produced grapes characterized by disubstituted anthocyanins and wines with lower content of total anthocyanins. North facing slope preserved higher acidity and malic acid levels in both grapes and wines. The year effect in the sandy cru appeared to be less pronounced probably due to better drainage and resilience of this soil to variable rainfall. Transcriptomic analysis revealed distinct and differential gene expression patterns associated with different soils and vineyard slope exposures, providing insights into the physiological mechanisms underlying these differences. These results further emphasize the importance of environmental factors , even within the same wine farm in shaping grape and wine quality with distinctive regional characteristics.
The third focuses on the role of advanced monitoring technologies in optimizing vinification processes. Near-infrared (NIR) spectroscopy and electronic nose (e-nose) systems were employed to monitor must composition during fermentation. NIR spectroscopy effectively predicted key parameters such as polyphenols, anthocyanins, and sugar content, while e-nose systems distinguished different fermentation stages and predicted the concentration of volatile compounds such as C6 alcohols, ketones, and terpenes. These (NDAT) offer rapid, cost-effective real-time data that enable continuous monitoring of key fermentation parameters. When supported by robust calibration models built from extensive multi-year datasets, these approaches offer exceptional reliability and precision that, in perspective and with the specific adjustments, could also be adapted for a monitoring of specific ripening-related parameters of the berries in the field.
The accurate monitoring of berry ripening is a crucial step for top quality viticulture and wine making. Non-destructive analytical techniques (NDAT) tools, such as NIR spectroscopy and e-nose systems, may enable rapid, real-time assessment of grape composition, supporting decisions on harvest timing and winemaking strategies. Their future integration into traditional practices depends on the development of specific and targeted devices, that must be optimized for these purposes and application.
These topics have been addressed in the present dissertation which specifically reports results regarding: (1) the effects of canopy management protocols (basal leaf removal, cluster thinning) on aroma compounds, particularly monoterpenes, in Moscato Bianco grapes; (2) the impact of different soils and vineyard slope exposures on Sangiovese grapes and wines in the Chianti Classico area, and (3) the integration of advanced monitoring technologies to optimize the vinification processes.
The first addresses the issue of the decline in monoterpenes, key aroma compounds in Moscato Bianco grapes and wines, as observed by winemakers and viticulturists in the Asti DOCG area of Piedmont. To tackle this issue, the impact of canopy management techniques -specifically basal leaf removal at veraison and at post-berry set and cluster thinning at veraison- on the accumulation of monoterpenes was investigated. Conducted over two growing seasons in two distinct vineyards at different altitudes within the Asti DOCG region, this research highlights the importance of microclimatic modifications in shaping grape composition and preserving the aromatic quality of Moscato d’Asti and Asti Spumante wines. In the vineyard located at lower altitude, leaf removal at veraison (VER) and cluster thinning (THIN) significantly enhanced the accumulation of monoterpenes particularly at the time T2 (corresponding to the commercial harvest for Moscato d’Asti wine production). Conversely, in the higher-altitude vineyard, the effects of the treatments were less pronounced at the timeT1 (harvest for Asti Spumante) and showed limited benefits at T2, highlighting the importance of site-specific management of the applied protocols. These findings underscore the role of microclimatic conditions, such as light exposure and thermal variability, in shaping aroma compound accumulation and the need for tailored viticultural practices to achieve desired aromatic profiles.
The second reports data, collected in two consecutive years on the influence of soil type and vineyard slope exposure on Sangiovese grapes grown in the same wine farm located in the Chianti Classico area. Three different types of soil were taken into consideration, one predominantly sandy and two predominantly clayey, corresponding to three distinct Sangiovese cru (FZ7, M17, ML6), having the same clone (R24) and the same rootstock (1103P), with south and north slope exposure, respectively. Transcriptomic analysis and metabolomic profiles were monitored weekly at three time points prior to the harvest date. Clay-rich soils were associated with higher concentrations of tri-substituted anthocyanins, such as malvidin derivatives, which contribute to color stability. In contrast, sandy soils produced grapes characterized by disubstituted anthocyanins and wines with lower content of total anthocyanins. North facing slope preserved higher acidity and malic acid levels in both grapes and wines. The year effect in the sandy cru appeared to be less pronounced probably due to better drainage and resilience of this soil to variable rainfall. Transcriptomic analysis revealed distinct and differential gene expression patterns associated with different soils and vineyard slope exposures, providing insights into the physiological mechanisms underlying these differences. These results further emphasize the importance of environmental factors , even within the same wine farm in shaping grape and wine quality with distinctive regional characteristics.
The third focuses on the role of advanced monitoring technologies in optimizing vinification processes. Near-infrared (NIR) spectroscopy and electronic nose (e-nose) systems were employed to monitor must composition during fermentation. NIR spectroscopy effectively predicted key parameters such as polyphenols, anthocyanins, and sugar content, while e-nose systems distinguished different fermentation stages and predicted the concentration of volatile compounds such as C6 alcohols, ketones, and terpenes. These (NDAT) offer rapid, cost-effective real-time data that enable continuous monitoring of key fermentation parameters. When supported by robust calibration models built from extensive multi-year datasets, these approaches offer exceptional reliability and precision that, in perspective and with the specific adjustments, could also be adapted for a monitoring of specific ripening-related parameters of the berries in the field.
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