The role of tannic acid in developing pea protein isolate-based active food packaging films

The interaction between plant-based proteins and polyphenols holds great promise for developing active films derived from renewable sources. This work aims to develop pea protein isolate (PPI) films incorporated with 2 %, 6 %, and 10 % tannic acid (TA) for potential use in active food packaging. The SEM images showed films with a compact microstructure and with no apparent pores. Incorporating 10 % TA into the PPI films enhanced their tensile strength from 3.86 MPa to 6.45 MPa, reflecting a 67 % improvement. Despite reduced elongation at break compared to the control film, the 10 % TA incorporation maintained over 500 % elongation, as many commercial thermoplastics used in packaging. Moreover, the films containing TA exhibited significantly reduced water vapor permeability, with the 10 % TA formulation showing an 87.9 % decrease compared to the control sample. The films also demonstrated increased hydrophobicity, indicating enhanced moisture resistance, while simultaneously improving their optical properties through greater UV-light barrier efficiency. The incorporation of 10 % TA enhanced the antioxidant capacity of up to 61 % DPPH radical scavenging and created a 12.98 mm inhibition zone against Staphylococcus aureus. Therefore, the findings suggest that PPI-based films incorporating 10 % TA are promising candidates for sustainable active food packaging solutions.