The release kinetics of functional compounds from active packaging systems plays a crucial role in determining their efficiency, as it directly affects the availability of the incorporated agents and the extension of the product’s shelf life. Therefore, controlled release behaviour is essential for optimizing the functionality of such materials. In the present study, corona treatment was used as a surface modification technique to tailor the release behaviour of polyphenols—curcumin, quercetin, and rutin—from polylactic acid (PLA) films. Polyphenol release was performed in a model medium (3% acetic acid), and the experimental data were fitted using commonly applied kinetic models to elucidate the release mechanism. The results indicate that corona-treated films exhibit significantly accelerated release kinetics and higher cumulative release compared to untreated samples. To interpret the observed behaviour, different surface characterization techniques were applied. Scanning electron microscopy (SEM) revealed only minor changes in the morphology of the uncharged and charged samples, which are unlikely to account for the observed differences in the release behaviour. Fourier transform infrared spectroscopy (FT-IR) confirmed that corona treatment has led to formation of new peaks in PLA spectrum and change in the shape and intensity in PLA–polyphenol loaded films. Contact angle measurements demonstrated increased surface wettability after treatment. These changes are associated with enhanced polymer–medium interactions and improved mobility of the incorporated polyphenols, leading to accelerated release. These findings demonstrate that corona treatment is an effective strategy for tuning the release kinetics of PLA-based systems. The developed materials show strong potential for use in active packaging applications, where controlled release of antioxidant compounds is essential for extending product shelf life.
Marudova et al. (Tue,) studied this question.