Characterization and functional properties of novel nanocomposite sericin-based films incorporated with sericin nanoparticles

Abstract

Sericin is an interesting protein that can be formed into sericin films for biomedical and food applications. Moreover, sericin can be prepared as sericin nanoparticles (SNs) and incorporated to enhance the film barrier properties. The SNs had a size of 407 nm, as verified by dynamic light scattering. To improve the mechanical properties of sericin films, pectin was added at different ratios of sericin:pectin (w:w) (3:0, 3:1, 3:2, and 3:3). Additionally, various amounts of SNs (0, 5, and 10%) were incorporated to form nanocomposite sericin-based films. The addition of pectin and SNs led to lower solubility and higher water vapor permeability than sericin film alone. The Fourier-transform infrared results showed that the interaction between sericin and pectin molecules increased the tensile strength of the films. Furthermore, the differential scanning calorimetry results indicated that adding pectin to sericin films increased the melting temperature, resulting in improved thermal stability of the composite films. However, higher pectin content reduced the total phenolic content and antioxidant activity. Nonetheless, SNs incorporation helped increase the antioxidant activity of composite films. Thus, the nanocomposite sericin-based films could be an alternative for food packaging materials or biomedical applications.