Scalping of ethyloctanoate and linalool from a model wine into plastic films Fabio Licciardello a , Matteo Alessandro Del Nobile b , Giovanni Spagna a , Giuseppe Muratore a, * a Section of Food Technologies, DOFATA, University of Catania, via Santa Sofia 98, 95123 Catania, Italy b Department of Food Science, University of Foggia, via Napoli 25, 71100 Foggia, Italy article info Article history: Received 25 July 2008 Received in revised form 27 December 2008 Accepted 8 January 2009 Keywords: MHS-SPME Multilayer structures Polarity Scalping Wine aroma abstract The scalping of aroma compounds may affect the sensory properties of wines packed in plastic, such as those commercialized in aseptic multilayer packages, by reducing the intensity and changing the char- acter of the original aroma. Up to date, no study has focused on the scalping of wine aroma compounds. The present study aimed at determining the sorption kinetics of two wine volatiles, chosen on the basis of their low threshold and high odor activity value, in linear low density polyethylene (LLDPE) and cast polypropylene (CPP), from a model solution simulating wine composition. The experimental data were satisfactorily fitted by the Fick’s Second Law, as to prove an ideal Fickian transport diffusional character of the phenomenon. Sorption was determined by means of MHS-SPME, a technique recently developed to quantify volatile compounds from solid matrices. Ethyloctanoate was sorbed more into CPP than LLDPE, and at much higher extent than linalool, as a consequence of the different polarity of the molecules. The amount of ethyloctanoate lost at the steady state determines a significant variation of its odor activity value and the imbalance of the original aroma composition. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction The transfer of food constituents into the packaging (scalping), as well as the transfer of contaminants from the packaging to the food (migration) often causes the loss of quality of the packed produce. On one hand, migration influences the safety of the packed food, whereas scalping affects its sensorial properties. Scalping, as well as permeation, result in the loss of the aroma of the product and, more in detail, it can determine the loss of aroma intensity and/or the change in aroma profile. This latter phenomenon is explained by the affinity that different aroma compounds, usually belonging to different chemical species, have for the plastic phase, therefore some compounds can be absorbed and/or permeate at a higher extent than others, causing the change of the original ratios between volatiles and, consequently, the change in the character of the aroma (Kwapong & Hotchkiss, 1987). The scalping of volatiles not only affects the properties of the contained product, but can also determine changes in the performance of the plastic material itself, such as the enhance- ment of the permeability to aroma compounds and oxygen (Sadler & Braddock, 1990; Togawa, Kanno, Horiuchi, & Kobayashi, 2001), or delamination of multilayer structures (Schroeder, Harte, Giacin, & Hernandez, 1990). Sadler and Braddock (1991) made a difference between the two approaches which can be used to study the sorption of aroma compounds, one is based on the loss of aroma from a solution put in contact with plastic, the other is based on the determination of the volatiles sorbed by the plastic phase. Early studies have mainly exploited the former approach. However, some concern exists about the reliability of such studies, as the loss of the aroma compounds could, in some cases, be due to degradation of the volatile itself more than to sorption by the contact material. Moreover, such studies do not give information about the nature of the sorption phenomenon (ad- or ab-sorption – i.e. the adhesion of the aromatic compounds on the surface of the polymer, or a proper diffusion of the molecules through the thickness of the material), about the solubility and diffusion coefficient of the aroma into the polymer (Sadler & Braddock, 1991). No study concerning the sorption of aroma compounds into plastic considers the odor threshold (i.e. the minimum concen- tration required for the odorant to be perceived) and odor activity value (i.e. the ratio between the concentration of the aroma and its odor threshold) of volatiles: this approach helps focus on the most sensorially important interactions among all, and can help quantify the changes in the aroma composition. Researches focusing on the sorption of wine volatiles into plastic are lacking: on a recent review on scalping of flavors in packed foods, no study can be found concerning wine aroma compounds (Sajilata, * Corresponding author at: Section of Food Technologies, DOFATA, University of Catania, via Santa Sofia 98, 95123 Catania, Italy. Tel.: þ39 95 758 0210; fax: þ39 95 714 1960. E-mail address: g.muratore@unict.it (G. Muratore). Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt 0023-6438/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.lwt.2009.01.007 LWT - Food Science and Technology 42 (2009) 1065–1069