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.

Ethnomedicinal, phytochemical and pharmacological investigations of Baccharis dracunculifolia DC. (ASTERACEAE)

“…For this, they lyophilized the extract and analyzed its antimicrobial and antioxidant characteristics before producing the film. The antimicrobial activity against Gram-positive bacteria, found by Casagrande et al (2021) , was better when compared to the liquid extract ( Casagrande et al, 2018 ). For S. aureus and B. cereus the MIC was 1.49 mg/ml, and 0.37 mg/ml, respectively.…”

“…The antioxidant activity of the DPPH, ABTS, and FRAP methods was better at 389%, 322%, and 533%, respectively, when compared to the liquid extract (Casagrande et al, 2018). The embedded film maintained the antioxidant action when analyzed by the DPPH method (Casagrande et al, 2021). Guimarães et al (2012) evaluated the antioxidant activity in vitro and hepatic mitochondria, isolated from rats, of the glycolic extract from the leaves of B. dracunculifolia.…”

“…Still, attention is drawn to the antimicrobial activity of the hydroalcoholic extract against Pseudomonas aeruginosa , with MIC and MBC of 51 mg/ml and resistance to ampicillin ( Casagrande et al, 2018 ). This same research group evaluated the addition of the hydroalcoholic extract at different concentrations in a film based on poly (vinyl alcohol) and starch ( Casagrande et al, 2021 ). For this, they lyophilized the extract and analyzed its antimicrobial and antioxidant characteristics before producing the film.…”

“…For P. aeruginosa , the MIC was higher than the concentrations analyzed. After being added to the film, the antimicrobial activity was reduced and even inhibited for the microorganisms mentioned above ( Casagrande et al, 2021 ).…”

“… Casagrande et al (2018) , evaluating hydroalcoholic extract and acetone extract, verified antioxidant activity by the methods of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2.2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), FRAP (ferric reducing/antioxidant power) which may be associated to the phenolic compounds in its composition, with ferulic acid (hydroxycinnamic acid) ( Supplementary Figure S4 ), being the main component ( Casagrande et al, 2018 ). Casagrande et al (2021) evaluated the same lyophilized hydroalcoholic extract as a pre-test for addition to a film based on poly (vinyl alcohol) and starch. The antioxidant activity of the DPPH, ABTS, and FRAP methods was better at 389%, 322%, and 533%, respectively, when compared to the liquid extract ( Casagrande et al, 2018 ).…”