Potencial antioxidante em filmes copoliméricos produzidos a partir de PVA e gelatina incorporados com quercetina como protótipo para embalagens ativas

Abstract

Due to multiple functions, packaging plays a main role in food. Many packaging systems have been developed to interact in the desirable manner with the product – the so called active packaging - changing the packaging conditions to increase the shelf life and to improve the security or sensory properties of the product, while maintaining its quality. Films incorporated with antioxidant agents are being widely used in this sense, because they act as a way to improve the stability of products that are prone to oxidation. The goal of this work was to evaluate the potential activity of PVA/gelatin films incorporated with quercetin for further study of their properties, as well as quercetin controlled release. Such films were prepared by the casting method and the obtained films were characterized by means of TG/DSC, FT-IR spectroscopy and optical microscopy and swelling index. Antioxidant properties were evaluated with DPPH, ABTS and FRAP assays and profile release study of quercetin was also performed. In order to simulate different types of food, standard solvent solutions were prepared. Ethanol:water (95:5; v/v) was used to simulate fatty foods, ethanol:water (10:90; v/v) simulated alcoholic and acetic acid:water (3:97; v/v) simulate acidic foods. According to the results, the thermal characterization showed that the film was stable up to 68°C and completely degraded at 632°C and with FT-IR spectroscopic analysis it was observed that there were physical interaction between the quercetin and the polimeric film. Optical microscopy indicated the existence of homogeneity and uniformity in the film. The study of release profile of quercetin, showed that ethanol:water (95:5; v/v) system proved to be a better option, because this is the system with higher extraction capacity compared to others. The 30 min extraction showed to be the better option for release profile and can perform reading from 20 min of reaction between DPPH and antioxidant. The film showed DPPH and ABTS radicals potential activity and potential iron reduction activity (FRAP), especially when analyzed in the ethanol:water (95:5; v/v) system. Hence, it is concluded that PVA/gelatin films incorporated with quercetin have properties that allow a potential application in active packaging systems, as a way to delay oxidative process in food, especially those with higher lipid content.