Release of Active Agents from Food Packaging Materials

Active packaging (AP) is an innovative type of food packaging from which active compounds, such as antimicrobials or antioxidants, may be released in order to enhance food quality and safety and extend its shelf-life. The efficiency of the AP system depends on the release rate, since too high rates may lead to a premature loss of the AP activity, while too low rates may not be sufficient to prevent food deterioration. In this context, the study of the active agent release mechanisms and kinetics is pivotal to determining the performance of AP systems. Here we describe a general method to evaluate the release of an active compound from a (bio)polymeric film, including the protocol for the release test, the quantification methods, and the mathematical models used to estimate diffusivity and elucidate the release mechanism. As a showcase, we focus on the release of the antimicrobial natamycin entrapped in a biopolymeric matrix to a food simulant liquid medium (ethanol solution), and we provide suggestions and protocols that can be extended to other biopolymers and analytes.