Characterization and modeling of diffusion kinetics of rosemary oleoresin extract from gellan gum-based film

Fresh food products are highly prone to oxidation and microbial attack, rendering them unsuitable for consumption. Thus, active food packaging was developed to protect and prolong food shelf-life. Zein/gellan gum (GG) based active film is developed by incorporating rosemary oleoresin extract (ROE) (0-20%). The films were characterized by their barrier and antioxidant properties. The release behavior of ROE in fatty and hydrophilic food stimulants was investigated via mathematical modeling. The active films incorporated with 20% ROE have significantly higher oxygen barrier and oxygen transfer is reduced by 20% compared to the control. A tortuous path is created with ROE, which impedes oxygen movement across the film. ROE addition improved water resistance performance by reducing the active film swelling ratio by 31%. This improvement is attributed to the hydrophobic nature of ROE. FTIR shows that the interaction between ROE and the active film is primarily hydrogen bonding and electrostatic interactions. Active film exhibits excellent antioxidant activity, with high TPC, DPPH scavenging activity, and FRAP. Mathematical modeling revealed a higher diffusivity (D) of ROE in fatty food stimulants at 24 °C, attributed to high polarity and solubility in fatty food stimulants. Overall, this active film has an excellent antioxidant effect and could potentially be used as food packaging for high-fat food products to prevent oxidation.