Study of Malvasia di Candia Aromatica shelf-life: effect of time and temperature on aroma compounds through an HS-SPME GCxGC-Ms approach

Abstract

Young white wines should be consumed within a short time after bottling to avoid loss of their fresh, fruity attributes. Shelf-life of white wines can be extended if they are stored under suitable conditions of time and temperature prior to consumption¹. The acidic environment plays a major role on the evolution of wine bouquet, promoting several reactions such as formation and hydrolysis, oxidation and cyclization. The aim of this study was to evaluate the effect of time and temperature on the aromatic composition of white wines (Malvasia di Candia Aromatica) coming from different vigor zones (High (HV);Low (LV);control) of the same vineyard.

After the vigor determination along the season², a prescription map was used for a mechanical selective harvesting. For each vigor zone, 30 kg of grape were sampled, stored in cool anoxia until processing. At the end of the fermentation, the wines were stored for 12 months at 5,15,25°C and sampled at 0,3,6,9,12 months. The Aromatic profile was performed by a SPME-HS-GC×GC-MS system. Data analysis was performed by MetaboAnalyst 6.0.

At the harvest, the LV grape showed the highest level of sugars and lowest total acidity than the C and HV, while for pH value no significant differences were detected among the treatments. Therefore, the LV wines showed the highest alcohol content and pH values, and lowest total acidity compared to HV and C. A pool of 78 volatile compounds were quantified. The LV wines showed higher concentrations of terpenes respect to HV and Control wines³. To evaluate the effect of time and temperature, OPLS-DA were applied, then the VIPs behavior was defined with FC analysis. For storage time, the most characterizing compounds were terpenes and were mainly down-accumulated over the time. On the other hand, 1,3,8-p-Menthatriene, p-Mentha-1,5,8-triene and β-Myrcene were up-accumulated. For the temperature, more heterogenous results were obtained: both terpenes and esters characterized the change of aromatic profile and both down and up-regulated compounds were recorded. Among terpenes, a general reduction (Linalool;Geraniol; β-Myrcene) coupled with the increase of their oxidated and derivates forms (Nerol oxide;Linalool oxide) was recorded. These preliminary data confirmed the expected differences in aroma composition among wines (LV;HV;C), especially for terpenes¹. According to the data, the aroma compounds follow the available literature, especially when stored for a long time at higher temperatures⁴.

References

[1] Slaghenaufi et al., (2018). Frontiers in chemistry, 6, 66.

[2] Gatti, M. et al., (2016). Sensors, 16(12), 2009.

[3] Bramley, R. G. V. (2022). Precision Viticulture: Managing vineyard variability for improved quality outcomes. In Managing wine quality. Woodhead Publishing.

[4] Waterhouse, A. L. et al., (2024). Understanding wine chemistry. John Wiley & Sons.