ABSTRACT
The design of packaging systems has a crucial significance for the useful utilization of high pressure processing (HPP) of food. In the first part, chapter 4 summarizes the general requirements on food packages for HPP including the flexibility (enabling the transfer of pressure from the pressure transmitting fluid to the food inside the package), perfect integrity, proper barrier characteristics, resistance to the total volume changes, etc. The suitable flexible and/or semi-rigid packages comprise the polymer bottles (made of polyethylene terephthalate or high density polyethylene) or the packages formed from layered polymer films (e.g. sachets, thermoformed or semi-rigid trays sealed with a film). Flexible packaging materials include mostly laminated films formed with a sealable layer (polyolefin), a barrier ply (polyamides, polyesters, metalized polymer films, aluminium foil, films with silicone deposit, polyvinyl dichloride, ethylene vinylalcohol copolymers) and sometimes with a mechanically resistant outside layer (polyamides, polyesters).
The second part of the chapter is focused on the influence of HPP on functional properties of polymer packages, i.e. their thermal resistance, mechanical properties and film delamination, barrier properties, migration parameters and aroma scalping. All reviewed information indicates that most of packaging films commonly utilized for food with extended shelf life (food products packaged in modified atmosphere, dried, pasteurized and/or sterilized products, etc.) are suitable for foodstuffs preserved by HPP. The HP resistance of polymer based packaging materials depends on particular conditions of HPP treatments and properties of the chosen packaging material (i.e. characteristics of its component layers including applied adhesives). In any case, the packaging system design for HPP food products must secure the safety of food production. It is generally recommended to omit packages combining layers of polymer and inorganic materials.
