Analysis of mechanical traction in biofilms chitosan and clay aiming fruits coating Analise de tração mecânica em biofilms de quitosana argila visando revestimento de frutas

A new concept of food packaging has been studied and developed in order to meet the application needs of the market. The application of such biofilms coating is directly related to its characteristics and possible interactions of these with the product and the environment. There is evidence that chitosan is a viable alternative to be applied in the coating for fruit characteristics antifungal, antibacterial and its direct action as a barrier to water vapor, which is the latest aging fruit. The clay, besides increasing permeability to water vapor, enables a greater adhesion of the film on the fruit surface. This paper presents the results that were obtained from the development of chitosan films aimed at applying the coating of fruit. It were made tensile test with films using different chitosan and clay concentrations. The tests followed the standards of ASTM D882/02. The best results were obtained for the coating of chitosan in 2% acetic acid, which showed a plastic strain of 4.4% and a maximum stress at rupture of 50.2 MPa. The results were lower for the films with the addition of clay; the best result was observed for this coating with chitosan to 2% clay plus 2% acetic acid, with plastic deformation of 2.9% and maximum stress at rupture 18.9 MPa.