Bacterial cellulose/kappa-carrageenan polymeric films incorporated with algae extracts (K. alvarezii and P. boergesenii) and the effects of gamma irradiation

This study aimed to develop and characterize active films of the bacterial cellulose and kappa-carrageenan (BC/KC) incorporated with aqueous extracts from two seaweed species: Padina boergesenii (EP) and Kappaphycus alvarezii (EK). The extracts demonstrated moderate antioxidant activity, particularly in the ABTS + assay, with EP showing superior performance (54.63%). Chromatographic analysis confirmed the presence of phenolic compounds such as cinnamic acid, gallic acid, chlorogenic acid, and rutin, with EP displaying a higher total phenolic content (25.50 μg/mL) than EK (8.60 μg/mL). Both extracts also exhibited antimicrobial activity. The films were subjected to gamma radiation at a dose of 25 kGy, and FTIR and XRD analyses indicated that neither the incorporation of extracts nor the irradiation altered the films' chemical structure. Incorporation of the extracts improved the thermal stability, antioxidant and antimicrobial properties, and decreased the water vapor permeability of the films. Among all samples, the irradiated EP4-S film stood out with enhanced functional performance, including a supportive antioxidant function, selective antimicrobial effect, thermal stability up to 280 °C, and an effective water vapor barrier. These results support the potential application of BC/KC films enriched with seaweed extracts as sustainable and functional active packaging. Further studies should address their mechanical behavior, real food preservation performance, and biodegradability.