Filmes biodegradáveis contendo extrato de bagaço de malte: desenvolvimento e potencial antioxidante.

Abstract

There is a growing concern about the disposal of industrial waste and the consequence that this act brings to the environment. Thus the reuse of these wastes is a possible alternative for sustainability. The use of malt bagasse, which is a by-product of the brewing industry, becomes a possibility for this problem. This by-product is rich in phenolic compounds that have antioxidant action, and its use in cosmetic products to maintain skin health is interesting. This work aimed to develop biodegradable films formulated with cassava starch and poly (vinyl alcohol), glycerol and malt bagasse extract. Later, to evaluate the content of total phenolic compounds, antioxidant activity (ABTS•+), and (DPPH• ) of the extracts and the mechanical, optical and barrier properties of the films, as well as the release kinetics of total phenolic compounds from the biodegradable films. The extraction of bioactive compounds from malt bagasse was performed by the Soxhlet technique, using acetone as solvent. The antioxidant activity of malt bagasse extract evaluated by the ABTS•+ method showed IC50 results of 2.0 ± 0.6, meanwhile the antioxidant activity by the DPPH• method showed the result of 196.0 ± 18.6 for the IC50 The phenolic content for the extract was 310.1 ± 62.6 mg EAG/g. Regarding the characterization of the films, the increase in the proportion of malt bagasse extract resulted in denser films, recording higher density values for the 3% (0.063 ± 0.009 g/cm3 ) and 5% (0.058 ± 0.015 g/cm3 ) formulations. It was possible to notice that there was a release of phenolic compounds in the films evaluated, using acetone as a solvent, at both samples there was an increase in the content of phenolics released by the films as a result of time, reaching values of 217.8 mg GAE/mL for Film 3 % (m/m) and 201.6 mg GAE/mL for the 5% (m/m) Film at the end of 4 hours. In the aqueous medium, both the 3% film and the 5% film showed an increase in the content of phenolics released as the result of time. It was recorded values of phenolic compounds of 163.3 ± 20.9 mg GAE/mL for the 3% Film and 165.7 ± 23.6 GAE/mL for the 5% Film at the end of 4 hours. The microstructural analysis of the films indicated that the Standard Film presented a continuous, smooth, and homogeneous characteristic, without pores, cracks, or irregularities. With the inclusion of malt bagasse extract, the surface of the films became more heterogeneous, and an increase in roughness was observed, suggesting that higher concentrations of malt bagasse extract altered the regularity and homogeneity of the polymer matrix. The mechanical performance of biodegradable films was not significantly influenced by the inclusion of extracts as well as their permeability to water vapor. The inclusion of malt bagasse extract resulted in biodegradable films with promising physicochemical properties and antioxidant potential, which can represent an alternative to be applied to obtain anti-aging masks.