Formulação e caracterização de filmes biodegradáveis de fécula de mandioca incorporados com polpa de manga e extrato de erva-mate, e seu efeito na preservação de alimentos

Abstract

The great interest in developing biodegradable films is motivated by its contribution to environmental preservation, apart from being possible to produce them from renewable sources. Among the biopolymers, cassava starch have been considered as one of the most promising material for this purpose because it is inexpensive and available worldwide. The objective of this study was to evaluate the incorporation the mango pulp and yerba mate aqueous extract as a source of antioxidants compounds and plasticizer glycerol in cassava starch based edibles films using a response surface methodology design experiment. The storage of palm oil packed in films containing additives rich in active compounds (0-20% m/m of mango pulp and/or 0-30% m/m extract of yerba mate) was monitored for 45 days under accelerated oxidation (63% UR/30 º C). The total polyphenols (TP), total flavonoids (TF) and total carotenoids (TC) of films and total carotenoids (TC), peroxide index (PI), conjugated diene (CD) and hexanal (HE) content of the packaged product (palm oil) were periodically monitored. The same analysis also evaluated palm oil packed in low density polyethylene films (C1), palm oil with no package (C2), and palm oil packed in bio-based films without antioxidants additives (C3), all used as controls. The total solids, thickness, moisture, water vapor permeability, elongation and tensile strength of 11 formulations were also evaluated. From the study, it can be concluded that the flexible films developed with naturals additives in cassava starch matrix has a great antioxidant activity. However, those results were more expressive with the use of yerba mate extract, because the response surface graph indicates that the point of minimum increase of peroxide index corresponds to the maximum concentration of yerba mate. The incorporation of additives also caused changes in the physico-chemical and mechanical properties of films with variations in thickness (from -1.77 to +10.62%) in total solids (from -0.33 to -4.12%), moisture (from +2.59 to +32.68%), permeability to water vapor (from -33.26 to +11.05%), elongation (from -1.31 to - 21, 53%) and tensile strength (from -25.09 to -74.72%). Therefore, the incorporation of the mango pulp and yerba mate extract in biofilms of cassava starch resulted a pronounced protective effect against lipid oxidation, altering the physico-chemical and mechanical properties, with enphasis in permeability to water vapor and tensile strength reductions of biofilms.