Packaging functions and their role in technical development of food packaging systems: Functional equivalence in yoghurt packaging
Using examples of yoghurt packagings - 115 g pack for Polylactic acid (PLA) versus Polystyrene (PS) and 150 g pack for Polypropylene (PP) against PS - the following study elaborates on the interaction between the choice of packaging material and resulting technical performance in terms of food packaging functions such as: stackability, oxygen barrier and water vapor barrier. Stackability was the critical parameter for material substitution in both packagings while oxygen and water vapor barrier were not found to be relevant. In 115 g pack, less amount of PLA (mass factor of 0.79), with thinner cup sidewall of 105 µm against 159 µm, provided the same functionality as PS. Whereas, in 150 g pack, equivalent mass of PP shows to provide the same functionality as PS, however, with thicker sidewall of 149 µm against 128 µm and 30% higher compression force. Finally, aforesaid, functional equivalency factors are factored-in to estimate environmental impacts of the packaging materials, so far on a cradle-to-gate basis, and identify potential for further improvements in packaging design.