Effect of dielectric barrier discharge atmospheric cold plasma treatment on structural, thermal and techno-functional characteristics of sodium caseinate

The present work aimed to study the effect of dielectric barrier discharge (DBD) atmospheric cold plasma (CP) on the structure-function relationship of sodium caseinate. The caseinate powder was subjected to CP for 0, 2.5, 5 and 10 min, and its physicochemical, structural, thermal, emulsifying and film-forming properties were investigated. The FTIR spectra revealed a higher β-structures and a diminished-random coil conformation after CP treatment. The DSC profiles confirmed higher glass transition in CP-processed caseinates. The CP-treated caseinates exhibited higher interfacial activity and developed emulsions with smaller particle size and higher physical stability. The SEM images and mechanical analysis of produced caseinate film showed that CP treatment up to 5 min promoted the formation of a more uniform microstructure and reinforced the tensile strength. These findings propose that CP treatment may be efficiently employed to mildly modify caseinate structure and improve its techno-functional properties. Industrial relevance: Cold plasma (CP) is an emerging eco-friendly efficient technology, which has gained increasing attention in the food and pharmaceutical industries. It is a potent and outstanding technique for non-thermal microbial decontamination, enzyme deactivation, surface modification, functionalization, and etching of coating materials. The CP may provide opportunities in a targeted modification of the structure and interfacial performance of biopolymers. This work demonstrates the potential of CP for mild modification of the structure, emulsifying and film-forming properties of sodium caseinate powder while maintaining its appearance features. Sodium caseinate treated by plasma can develop an emulsion with significantly higher physical stability and edible film with augmented mechanical strength, opening a wide range of promising applications in food and pharmaceutical industries such as the development of tailor-made protein-based films, coatings, emulsions, and emulsion films.