Novel insights into Passito wines aroma typicality. Rationalizing the markers of varietal and geographical origin of Amarone DOCG

Abstract

Valpolicella is a famous Italian wine-producing region (Paronetto & Dellaglio, 2011), whose main characteristic is the extensive use of the post-harvest withering technique, which takes place in naturally ventilated rooms called ‘fruttai’ (Bellincontro et al., 2016). With this technique, three PDO red wines are produced: ‘Ripasso della Valpolicella’, ‘Recioto della Valpolicella’, and the most famous ‘Amarone della Valpolicella’. The withering process involves a range of physical, physiological, and biochemical changes that significantly impact the final quality of the grapes and the consequently wine (Barbanti et al., 2008; Zenoni et al., 2016). The aim of this study was to identify chemical volatile patterns of varietal and geographical typicality of Amarone wines. This study considers different sample sets: a set of experimental wines produced from withered grapes of different origins and vintages (2017-2019), a large dataset of 45 commercial Amarone wines from different vintages (2015, 2016, and 2019), and a data set of 33 samples from two commercial Amarone labels of the same winery from old vintages (1974 to 2016). An accelerated aging treatment protocol was employed: samples were stored at 40°C and 16°C for 30 days. Free volatile compounds and glycosidic precursors were analysed with different GC-MS techniques. Enological parameters of wines were analyzed by the mean of multiparametric analyzer with specific enzymatic kits. Sensory characteristics of the wines have been investigated through sorting tasks performed with semi-trained panel.

This study highlighted the importance of certain volatile compounds of different biochemical origins, including fermentative and varietal origins such as 1,4- and 1,8-cineole, norisoprenoids, esters and DMS. The occurrence of these compounds has been attributed to specific compositional parameters of grapes and wine, such as terpinen-4-ol, pH, and PAN (Primary Amino Nitrogen).

Concerning geographical typicality, application of multivariate data analysis techniques allowed to identify volatile chemical profile representing the chemical signature of the geographical origin. Main drivers of the geographical pattern were norisoprenoids and terpenes. The latter, showed different patterns of typicality according to wine aging periods. Also, Amarone wines from older vintages (1974-2016), despite the impact of different vintages and aging periods, showed specific volatile chemical patterns for each wine, even after major chemical modifications due prolonged aging treatments.

Acknowledgement

Azienda Agricola F.lli Tedeschi is acknowledged.

References

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