C: Food Chemistry Effect of the Closure Type on the Evolution of the Physical-Chemical and Sensory Characteristics of a Montepulciano d’Abruzzo Ros´ e Wine Massimo Guaita, Maurizio Petrozziello, Silvia Motta, Federica Bonello, Maria Carla Cravero, Concezio Marulli, and Antonella Bosso Abstract: The present work studied the effect of the kind of closure (a screw cap, a natural cork, and 2 synthetic closures) on the evolution of the oxygen content and on the physical-chemical and sensory characteristics of a Montepulciano d’Abruzzo ros´ e wine during the 1st 12 mo of bottle aging. The chemical analyses concerned the parameters more involved in the oxidative reactions (SO 2 , acetaldehyde, phenols, wine color), as well as the main fermentative volatile compounds. The kind of closure influenced the oxygen content in wines, free and total SO 2 concentration, and wine color (color intensity and hue). During bottle aging, free and total SO 2 concentration was significantly and negatively correlated with absorbance at 420 nm (A420), whereas the correlations with A520 were weak. Probably, the limited extent of the variations in red color (A520), when varying SO 2 concentration, were due to the low pH of this ros´ e wine. No effect of the kind of closure on phenols and the main fermentative volatile compounds was observed. The wines bottled with cork closures (N trials), after 12 mo of storage, had higher color intensity and hue, measured by spectrophotometry, and were visually distinguished from the other trials for the more intense pink reflections. On the whole, under the conditions of this work, all the used closures guaranteed a good preservability to the ros` e wines during the 1st year of bottle aging, and the changes in composition did not significantly affect wine sensory characteristics. Therefore, these synthetic closures can represent an alternative to the cork closures for a medium to long term bottle aging of these wines. Keywords: bottling, closures, dissolved oxygen, headspace oxygen, oxygen transfer rate, Ros´ e wines Introduction Traditionally, the oenological research has been searching for winemaking techniques aimed at optimizing the physical-chemical and sensory characteristics of wines. More recently, an increasing number of studies is focusing on the preservation of wine qualita- tive characteristics during bottle aging (Ugliano and others 2009; Dimkou and others 2011). One of the main causes of wine qual- ity drops during bottle aging is the oxidative phenomena: in this respect, SO 2 still remains irreplaceable for preserving wine quality. During a wide study on Semillon wines regarding the comparison between different types of closure, Godden and others (2001) no- ticed a strong correlation between wine color (absorbance at 420 nm), measured after 18 mo of bottle aging, and the concentration of free SO 2 after 6, 12, and 18 months. The concentration of free SO 2 after 6 mo could even allow to predict the browning level that wines reached after 18 mo of bottle aging. According to these authors, 10 mg/L of free SO 2 can be considered the limit below which white wines start to show oxidized characters (off- odors, browning,. . . ). Other authors (El Hosry and others 2009), working with Lebanese white wines, proved that the tendency MS 20120767 Submitted 6/1/2012, Accepted 11/22/2012. Authors Guaita, Petrozziello, Motta, Bonello, Cravero, and Bosso are with Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per l’Enologia – via Pietro Micca 35 – 14100 Asti, Italy. Author Marulli is with Cantina Ciccio Zaccagnini – Contrada Pozzo -65020 Bolognano, Pescara, Italy. Direct inquiries to author Bosso (E-mail: antonella.bosso@entecra.it). to browning was related to various physical-chemical parameters such as pH, total phenols, and free SO 2 . The level of free SO 2 in bottled wines depends on its concentra- tion at bottling and, later, on the extent of its losses by oxidation: it is currently accepted that 1 mg/L of dissolved oxygen (DO) can consume 4 mg/L of free SO 2 . When wine is correctly managed before bottling by limiting its exposure to oxygen, the losses of free SO 2 will mainly depend on the amount of oxygen that en- ters the bottle during the bottling operations, that remains in the headspace immediately after sealing, and that will later permeate through the closures during bottle aging. Furthermore, due to their porous nature, cork closures contain O 2 which is adsorbed on the pores inside the cork and is in part released gradually into the headspace during the 1st months after bottling (Dimkou and others 2011; Ugliano and others 2011). Regarding bottling operations, Gibson and O’Brien (2006) proved that the gas that remains in the bottle headspace after sealing is the main source of oxygen exposure for bottled wine. In fact, bottle flushing with inert gas prior to filling cannot guarantee an oxygen-free headspace: both the bottle headspace and, when using screw-caps, the underside of the cap itself must be flushed with inert gas before sealing. Regarding the oxygen that permeates through the closures dur- ing bottle aging, it is well known how only a flame-sealed glass bulb is completely impermeable to oxygen. On the contrary, the different kinds of commercial closures are permeable to oxygen to an extent varying with the kind: the permeability of each kind of closure is measured as oxygen transfer rate (OTR: μg/day) (Lopes and others 2007). C  2013 Institute of Food Technologists R  C160 Journal of Food Science  Vol. 78, Nr. 2, 2013 doi: 10.1111/1750-3841.12022 Further reproduction without permission is prohibited