Development and characterization of wheat mill by-product films enriched with commercial rosemary extract

Abstract

This study aimed to develop and characterize an active film from a wheat mill by-product little explored, named Glue Flour (GF) enriched with a commercial rosemary extract (RE). First, RE was characterized by its antioxidant and antimicrobial properties. Subsequently, films were elaborated by the casting technique and characterized by the thickness, moisture content, solubility, mechanical and barrier properties, optical characteristics, and their bioactive activities. The RE concentrations tested in films were 1, 5, 10, and 20% (v⋅wwater-1). RE showed antioxidant potential and antimicrobial activity against Staphylococcus aureus and Aspergillus brasiliensis; however, it did not inhibit Escherichia coli growth. Film solubility and moisture were approximately 12 and 35%, respectively. The addition of RE weakened the films mechanical and barrier properties. As the color of RE is green, the films tended to this coloration, lost luminosity, and the opacity increase was proportional to the RE concentration. Low luminosity indicates better barrier properties against UV light. From Pearson's correlation test (p < 0.05), the films concentration of RE, antioxidant activity, and inhibition zone (IZ) demonstrated a positive and significant correlation. This study demonstrated a by-product and a commercial RE potential in developing active biodegradable films.