Kinetical approach of release and antioxidant performances of ι-carrageenan-based films modified by sodium alginate and Ca2+ and incorporating sea fennel essential oil and its major components.

Understanding whether antioxidant efficiency in active films is governed by release kinetics or intrinsic radical-scavenging reactivity remains insufficiently explored in hydrophilic biopolymer networks. This study investigates the coupling between release mechanisms and antioxidant reaction kinetics in ι-carrageenan-based films loaded with bioactive (chlorogenic acidor d-limoneneor sea fennel essential oil) to evaluate their release behavior and antioxidant activity. Release experiments were conducted in food simulant D1 (50% ethanol) over 48 h, while antioxidant activity (AA%) was monitored using the DPPHin the same simulant. Diffusion coefficients (D), kinetic rate constants, and times to reach 50% release (t50% release) or 50% antioxidant activity (tAA50%) were mathematically modeled. The originality of this work lies in quantitatively and qualitatively correlation between release and antioxidant activity kinetics. Interpenetrated ι-carrageenan-alginate and Ca2+-crosslinked ι-carrageenan networks enable discrimination between release-controlled and antioxidant reaction-controlled. Chlorogenic acid exhibited the fastest release (≈27% after 48 h; D ≈ 32 × 10-15 m2.s-1) and radical-scavenging activity, reaching high AA% (46%), indicating a predominantly release-controlled system. In contrast, d-limonene and sea fennel essential oil displayed significantly lower diffusivity (from 4 to 17 times lower), lower and slower AA (AA% from 2 to 3 times lower; tAA50% from 3 to 5 times higher) reflecting mass-transfer limitations and more complex reaction behavior within the matrix. Ca2+ crosslinking further modulated diffusivity and antioxidant performance by changing polymer network density. These findings provide mechanistic insights into how structural properties of hydrophilic polymer networks govern the balance between release and reactivity rates, offering a rational framework for designing active films with predictable and tunable antioxidant functionality.