Abstract
The aim of this study was to evaluate the volatile and phenolic profiles of three red and one rosé wines stored in bottles for 30 months. Four wines were provided by a winery located in South Tyrol (Kellerei Bozen, Bolzano, Italy), which included Merlot, Lagrein red, Lagrein rosé and St. Magdalener and were closed with different types of stoppers: a blend of natural cork microgranules and polymers without glue addition (Supercap Nature, Mombaroccio, Italy), a one-piece natural cork, agglomerated natural cork and a technical cork 1+1. Volatile compounds were extracted by head-space solid phase microextraction (HS-SPME) and then analysed by GC-MS, while the phenolic compounds were determined by HPLC-DAD-FLD. The type of stopper did not show significant differences on the chemical profiles of the wines. Instead, the interaction between the wines and the type of stoppers as well as the type of wines had a significant influence on the volatile and phenolic profiles. Regarding the volatile profile, significant differences were observed for ethyl butanoate and 2-hydroxyethylpropanoate which were present just in St. Magdalener and absent in Lagrein rosé wines, respectively. Also, 2-methylethyl butanoate and 3-methylethyl butanoate were not detected in both Lagrein red and rosé, whereas isopentyl acetate was found in Merlot wines at low concentration. On the other hand, 1-hexanol, ethyl hexanoate, ethyl octanoate and ethyl decanoate were found at high concentration in Lagrein rosé wine compared to the three red wines. Regarding the phenolic profile, results showed a low concentration of p-coumaric acid, protocatechuic acid, caftaric acid, (+)-catechin, (-)-epicatechin, S-glutathionyl caftaric acid (GRP) and syringic acid in Lagrein rosé wine with respect to the red wines. However, the concentration of gallic acid was higher in Merlot wine and differed significantly from the three others with the lowest value in the Lagrein rosé. The chemical profiles of the four wines were significantly influenced by the type of wine due to their grape variety and vinification processes. Conversely, the type of stopper did not show any significant differences in terms of volatile nor phenolic profile, due to the high technical quality of the closures under study.