###### Abstract  
Flavour scalping in wine is a well-known phenomenon that is defined as the sorption of flavour compounds on wine closures. While the impact of closure type was the object of several studies, no research has addressed the impact of wine closure permeability on flavour scaling. For that purpose, the adsorption of volatile sulphur compounds (VSCs) on four micro-agglomerated wine cork closures was investigated by soaking them in model and Shiraz wines for 7 days. From a kinetic point of view, most of the VSCs were quickly scaled after 1 h soaking, and this effect increased after 6 h until reaching a plateau. Most importantly, no significant impact of the closure on the kinetics and adsorption rates of the VSCs was found. As to the quantitative aspects, VSC sorption on closures accounted for 1% to 5% of the initial VSCs present in the wines only, meaning that the impact was negligible under enological conditions. volatile sulphur compounds; wine closure; scaling; sorption +
Footnote †: journal: Medical  
than for technological and natural cork closures (from 20% to 30% sorption). However, no case of scalping was observed for screw cap closures in the same study. For 2-phenylethyl acetate, higher levels were found in wines bottled with natural corks compared to synthetic closures, suggesting a higher scalping effect for synthetic closures due to the polyolefinic material used for its production [10]. 3-alkyl-2-methoxypyrazines, another flavour family, are also subjected to adsorption at the closure's surface [7]. These compounds, such as 3-isobutyl-2-methoxypyrazine (IBMP), 3-_sec_-butyl-2-methoxypyrazine (SBMP), and 3-isopropyl-2-methoxypyrazine (IPMP) were perceived as green and vegetative notes in wine [11; 12]. This study, performed on Riesling and Cabernet Franc wines, showed that scalping had the greatest impact on IBMP [7], but all molecules had a higher concentration scalped in bottles closed with synthetic closures compared to natural cork and screwcap closures. The same conclusion was reached on a Chardonnay wine, in which various cork products were soaked for 140 h [13]. Indeed, synthetic cork closures most affected wine concentrations in IPMP, IBMP, and SBMP (decreases of 77%, 70%, and 89%, respectively), followed by agglomerate and natural cork closures. SBMP was the most affected by scalping in this article. Other works suggested that cork could sorb volatile phenolic compounds [8; 9]. The investigation of seven phenolic compounds (guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-propylguaiacol, 4-vinylguaiacol, 4-ethylphenol, and 4-(2-propenyl)guaiacol) showed that all of them could be adsorbed on a cork's surface, with a higher sorption coefficient for the most hydrophobic molecules (from 125 mg/kg for guaiacol to 306 mg/kg for 4-(2-propenyl)guaiacol). The same study suggested that volatile phenols were trapped via weak interactions at the cork's surface. Moreover, the second study demonstrated the role of suberin, the major component of cork, as the component that had a higher sorption rate with volatile phenols compared to cork. This study, performed on two spoiled wines, showed that a large amount of the initial concentrations of 4-ethylguaiacol and 4-ethylphenol (49.2% and 44.6% for wine A and 66.8% and 71.2% for wine B, respectively) was sorbed by suberin. The adsorption of chloroanisoles by corks has been studied for a long time [14]. Indeed, during bottle ageing, natural cork closures can adsorb 2,4,6-trichloroanisole, 2,3,4,6-tetrachloroanisole, pentachloroanisole, 2,4-dichloroanisole, and 2,6-dichloroanisole from wine in an extremely slow way. These results were relatively identical to coated and uncoated corks. 1,1,6-trimethyl-1,2-dihydromethane (TDN) was observed to follow the same behaviour as volatile phenols: after 2 years of storage of a white wine, there was a higher scalping effect from a synthetic closure (96% and 98% of adsorbed TDN) compared to natural and technical cork closures (50% and 70% of adsorbed TDN, respectively) [6].