PREPARATION, CHARACTERIZATION AND ANALYSIS OF NANOSCALE MORPHOLOGY OF POLY(VINYL ALCOHOL) FILMS ASSOCIATED WITH SILK FIBROIN FUNCTIONALIZED WITH COPAÍBA OLEORESIN

Abstract

Biodegradable films based on poly(vinyl alcohol) (PVA) and bioactive substances have been receiving great attention in the food industry, as they offer an eco-friendly alternative to conventional packaging. In this context, we synthesized PVA (PVAF) films containing silk fibroin (SF) formulations functionalized with copaiba oleoresin (CO) for use as bioactive packaging. Four different formulations were prepared using the casting method, varying the SF-CO concentrations from 0 to 15% (v/v) in the PVA matrix. The samples were characterized regarding morphology, nanotexture, physicochemical, and barrier properties. SEM images revealed the uniform morphology of the films, and AFM data allowed the quantification of surface characteristics such as uniformity and homogeneity, confirming the uniform distribution of SF-OC in the PVA matrix. All films showed high water absorption power (more than twice their mass weight), and the incorporation of SF-CO did not change the water vapor permeability rate of PVAF. In contrast, the solubility of PVAF decreases with SF-CO content. FTIR and UV-vis spectra confirmed the presence of SF-CO in PVAF and indicated possible intermolecular interactions between PVA and SF-CO. Finally, our findings suggest that the incorporation of SF-CO into the PVA matrix is a viable alternative for producing eco-friendly packaging.