Nanoencapsulation and crosslinking of trans-ferulic acid in whey protein isolate films: A comparative study on release profile and antioxidant properties

Despite extensive research on incorporating nanocapsules into films, the efficiency of active compounds in affecting food and maintaining long-term packaging functionality remains a major challenge. Our study reports the fabrication of whey protein isolate (WPI) films via crosslinking and nanoencapsulation of trans-ferulic acid (TFA), respectively. Nanocapsules were prepared by ultrasonication, and their particle size and polydispersity index were determined. Results demonstrate that the incorporation of nanoencapsulated TFA significantly improves the antioxidant capacity of WPI films (5.18 %) during storage, maintaining up to 40 %, which is higher than crosslinking. The crosslinked TFA-WPI film exhibited enhanced oxygen barrier properties by 50 % owing to increased polymer density and crystallinity. The water vapor permeability significantly decreased by 77 % for both crosslinked and nanoencapsulated films owing to their polymer density and hydrophobicity, respectively. A controlled release test revealed nanoencapsulation of TFA in WPI film was beneficial for a higher released ratio of phenolic acids (99.55 %) and sustained antioxidant activity than crosslinking (73.77 %). The Higuchi model suggests that TFA are diffused from a homogeneous film matrix. Nanoencapsulation improved the water vapor barrier of WPI film and the long-term stability of TFA. Furthermore, improved oxygen barrier properties of WPI were observed due to the crosslinking while maintaining a mechanical strength higher than that of nano- encapsulation. Consequently, the WPI film demonstrates exceptional potential for food packaging applications due to its advanced gas barrier properties, the robust and sustained antioxidant activity of TFA, and the efficient release of TFA, without compromising functionality during storage.