Abstract
Closure systems ensure the sealing and a proper conservation of winery products. Up to date, no study has investigated the effect of stoppers on distillates. An interaction study was conducted on grappa (Italian fermented grape pomace brandy). This research aimed at determining the effect of the stopper material (synthetic stoppers and micro-granulated cork stoppers) on the volatile and sensory profiles of grappa bottles over 12 months of storage.
Volatile compounds were determined by gas chromatography-mass spectrometry (GC-MS) and the sensory profile was evaluated by a trained panel using quantitative descriptive analysis (QDA®). The variables considered for PCA were further analysed by two-way ANOVA (p<0.01) to evaluate the time of storage (T) and stoppers (S) as factors.
Higher alcohols and esters were the main volatile compounds in all the samples. Compounds up to 8 carbon atoms (2-methyl-1-propanol, 3-methyl-1-butanol, 1-hexanol, ethyl acetate, 3-methyl-1-butanol acetate and ethyl hexanoate) displayed a partial decrease after 6 months, then an increase up to 12 months. The storage time factor had a significant effect on clarity, color, floral and caramelized aromas, whereas no effect was found for stopper factor. Moreover, the interaction (TxS) was significant for color. PCA showed a temporal trend with an increase of several aroma descriptors (spicy, dried vegetative, caramelized and tree fruit) over time. The stoppers were clustered according to the time of storage, with exception for the micro-granulated cork stopper after 12 months, which mostly correlated with off-odor compared to the other stoppers.
The data obtained in this study can help producers to make decisions in terms of packaging, especially closure material, as a parameter that could impact the overall sensory quality and evolution of distillates into the bottle.