Filmes biopoliméricos de quitosana e nanofibras de celulose incorporados com papaína para a aplicação em carnes

Abstract

The objective of this work was to develop and characterize chitosan films with cellulose nanofibers incorporated with papain to improve the softness of bovine meat. The films were developed by the casting technique following a 3x4 complete factorial design with 3 levels of NFC (0, 4 and 8%) and 4 levels of papain (0, 2, 6 and 10%). The obtained films were characterized with respect to the mechanical, thermal, barrier properties, optics, water solubility, infrared spectroscopy (FTIR), X-ray diffraction, scanning electron microscopy and proteolytic activity. The study of the papain diffusion through the films was performed in films with 2% papain. The films were applied to beef steaks (M. Longissimus thoracis et lumborum -) for a period of 21 days storage at 2 °C to evaluate the softening effect of the package. Meat analyzes were: meat proteolytic activity, shear force (WBsSF), myofibrillar fragmentation index, color, pH and cooking loss. The results of the characterization analysis of the films indicated that films with up to 6% of papain and 4% of NFC showed improvements in most of the studied properties. The release study showed that the diffusion of papain in the chitosan films follows the Fickian mechanism and that the presence of NFC in the chitosan matrix acted to reduce the release of papain in aqueous medium. With the results obtained in the application of the films in the beef, it was observed that the films with 6% of papain were sufficient to promote an improvement in the tenderness of the beef stored for 21 days, when compared to the meat packaged with a commercial packaging.