Caracterização de filmes biodegradáveis de amido com extrato de erva mate

Abstract

Yerba Mate is a regional product, obtained through the leaves of the mate tree that belongs to the family Aquifoliaceae and has several compounds of food interest, such as phenolic compounds, antimicrobials and natural antioxidants. The antioxidant action of the yerba mate is due to the high content of the phenolic compounds present in the leaves. Thus, the use of bioactive compounds can promote health effects as well as prolong the shelf life of food, as ingredients and also as active packaging. Traditional food packaging, in general, has the function of protecting them, thus avoiding their degradation and also of possible losses through the migration of components. On the other hand, active packaging has the ability to interact with food retarding degradation and extending shelf life. Thus, it was aimed to elaborate starch films applying yerba mate extract, as well as to perform the physicochemical characterization. The extracts were made with different solvents (100% water, 100% ethanol and 50% water: 50% ethanol) at 50 °C followed by characterization by determination of density, chlorophyll and carotenoid content, phenolic compounds and antioxidant activity (ABTS•+ and DPPH•). Based on the results of the antioxidant activity, the best solvent for was selected, 50% of which was water: 50% ethanol. From this, films using cassava starch, glycerol and different concentrations of extract (0, 5%, 10%, 15%, 20%) were elaborated. In the films were characterized as thickness, water vapor permeability (PVA), mechanical properties solubility (tensile strength, percentage of elongation and Young modulus), phenolic compounds, antioxidant activity (DPPH•), color and opacity parameters and sorption isotherms. It was verify the films solubility increase with extract concentration increased, since the extract is water soluble. The starch films shown decrease in the tensile strength as the concentration of Yerba mate extract increased as well as extract promoted a plasticizing effect in cassava starch films, increasing the elongation. The Young maximum modulus was observed in the control film and reduced with the increase in the concentration of yerba mate extract. In addition, the behavior of the sorption isotherms was adjusted to the GAB model (R2> 0.96). The moisture absorption by the samples with 5, 10 and 15% were similar, being that they absorbed more humidity than the control. The objectives for the development and characterization of the biodegradable films were reached, being observed positive characteristics for the elaboration of active biodegradable films with the application of yerba mate extract.