# Chemical Migration from Wine Contact Materials
## 2 Wine Packaging Materials  
Food packaging serves several roles, the most important of which is the protection and preservation of the quality of the food or beverage content. It is anticipated to protect the beverage from any chemical, physical, or biological hazard and preserve its composition to be stable throughout its shelf-life. Food packaging has been evolving for thousands of years. From ancient amphoras dating back to 1500 BC [8] to modern active packaging containers [9] and composite paper bottles, wine packaging has come a long way. Glass and cork are still regarded as the most commonly used packaging materials; however, alternative packaging solutions such as lightweight glass, bag-in-box packaging systems, polyethylene terephthalate (PET) bottles, aseptic cartons, and aluminum cans are now sought after. Glass is considered the oldest and most traditional wine container. The popularity of glass lies mainly in its physical and chemical properties but also in its added value on consumer-perceived wine quality [10]. Among other advantages, glass forms a barrier against vapors and gases; it is odorless and chemically inert, can be manufactured in various formats, and can protect wine from UV radiation if treated properly. Wine in glass bottles has been traditionally sealed with natural cork (_Quercus Suber_ L) stoppers. In order to meet increasing stakeholder requirements in both economic and environmental aspects, agglomerated closure solutions have been employed. The latter closures are comprised of cork granules with typically 2-5% of binding factors, including phthalates and adjpates [11]. Cork-based closures undergo a surface treatment with food-grade paraffin and silicone to improve barrier properties and facilitate insertion and removal of the cork [4]. Apart from natural cork-based closures, other materials are also currently employed. These include closures made of aluminum and PET, tin, and plastic, mainly Low-Density Polyethylene (LDPE) with limited quantities of High-Density Polyethylene (HDPE) or Polypropylene (PP) [12; 13]. Plastic closures are designed to look like natural cork and are produced as compressed plastic. For that reason, they are much cheaper than natural cork. Unfortunately, this type of closure consists of a non-biodegradable material [14]. The polymers that are usually used for food are LDPE for co-extruded stoppers and styrene-butadiene-styrene (SBS) or styrene-ethylene-butylene-styrene (SEBS) for molded ones [15]. Although glass presents significant advantages for bottling wine, the increased energy requirements associated with glass production, the high transportation costs related to its heavy weight despite the adoption of lightweight glass, and the glass's susceptibility to breakage constitute its major drawbacks [16]. The latter has given rise to the increasing adoption of alternative wine packaging. One of these alternatives concerns bag-in-box systems, which appeared as a packaging alternative in the food industry in the late 50s and were first adopted for packaging wine in bulk around the 1970s. This type of container enabled wine packaging in larger formats, facilitated transport and stockage, and significantly contributed to the lowering of wine production's carbon footprint [17]. Bag-in-box systems consist of a flexible, welded composite \"bag\" equipped with a polypropylene valve fitting for pouring the wine and an outer rectangular paperboard \"box\" serving for mechanical protection. The inner layer of the bag is mainly produced from either ethylene vinyl acetate (EVA) or LDPE [18]. The outer layer, which can vary in composition with aluminum, polyethylene, polyamide, or linear LDPE being the most commonly used materials, serves as the high barrier layer [19]. The FCMs are commonly polyethylene or linear LDPE [19]. The packaging procedure consists of pre-evacuation of air through a vacuum, filling the bag with wine, and inert gas addition to remove the remaining headspace oxygen. As the container is emptied, the bag collapses, protecting the wine from oxygen.