Mixture Design for the Development of Biodegradable Active Strands Based on Acetylated Cassava Starch, Chitosan and Oregano Essential Oil

The extrusion of biopolymers allows the generation of a wide range of innovative and environmentally friendly products presenting multiple advantages for the food packaging sector. Additionally, the incorporation of antimicrobial agents such as oregano essential oil (OEO) promotes improvements in the functional, mechanical and barrier properties of films. In this context, a mixture design (simplex-centroid) of three components was carried out: Base Mixture (BM, acetylated cassava starch and glycerol), chitosan (CH) and OEO. The mechanical and antimicrobial properties against bacterial contamination of Enterococcus faecium were evaluated. The results of the special cubic model adjustments showed R2 values greater than 0.9963 for all evaluated responses. It was observed that all the components evaluated had significant effects on the responses. In particular, the system with the same amount of CH and OEO (8% w/w) showed high values of Young modulus (24 ± 2 MPa) and stress at rupture (0.92 ± 0.09 MPa) and minimum deformation values (27 ± 3%) indicating that a more resistant material is obtained. On the other hand, from the measurement of the inhibition zones, maximum values (14.1 ± 0.1 cm2) were obtained for the system with 85%BM/9.33%CH/5.33%OEO. Based on the results obtained, it is concluded that these formulations are attractive to be implemented in active food packaging.