Optical, Mechanical, Antioxidant and Antimicrobial Properties of Starch/Polyvinyl Alcohol Biodegradable Film Incorporated with Baccharis dracunculifolia Lyophilized Extract

Abstract

Biodegradable active films incorporated with lyophilized extract of Baccharis dracunculifolia, source plant of Brazilian green propolis, were prepared by casting method. The extraction conditions of the bioactive compounds were optimized to generate a lyophilized product that was added to the starch: poly(vinyl alcohol) (1:1 w/w) film at concentrations of 0%, 1.0%, and 1.5% (w/w). The addition of B. dracunculifolia extracts promotes a reduction in the mechanical properties and an increase in the opacity of the active biodegradable films, directly related to the B. dracunculifolia contend added. For the migration tests in the films, using different food simulants solvents, the antioxidant activity (DPPH) and the TPC were performed, and ranged from 71.64 to 215.06 μmol Trolox and from 14.57 to 40.95 mg GAE (Gallic acid equivalent), per gram of film, respectively. The active biodegradable films were efficient against the pathogenic microorganisms Escherichia coli and Salmonella enterica subsp. enterica. The HPLC analysis showed that the major components in B. dracunculifolia extract were catechin, followed by ferulic acid. According to the characteristics presented, B. dracunculifolia lyophilized extract is a promising product for incorporation in food or pharmaceutical formulas, or as an active food packaging, due to its antioxidant and bactericidal activities.