During HPP the pressure reaches up to 6,000 bar (87,000 psi). At this pressure, products will compress approximately 15% of their volume, meaning that HPP packaging must be waterproof, hermetically sealed, and include materials which are flexible to withstand compressions of at least 15%. For these reasons, different plastic materials have traditionally been a popular choice for HPP since many of these are flexible enough to allow containers to compress without breaking and elastic enough to retake their original shapes after the process. Additionally, several sustainable alternatives can be used with HPP such as rPET, PP, PLA and other biodegradable solutions.
Commonly used packaging and materials for HPP include bottles, cups, pouches, trays, in combination with various types of films or closures. Sealing surfaces for films need to be relatively wide, uniform and preferably flat. Sealability (heat seal strength) is an important element for packaging that is subjected to HPP. Cross-hatched patterns are not suitable as they can allow oxygen
diffusion into the packages that will contribute to oxidative deterioration of products.