Ultrasound and Microwave Treatments to Produce Flexible Thermoplastic Starch–Brewers’ Spent Grain Composite Films

). SEM micrographs allow us to observe that the film surface appears rough, and the structure becomes increasingly porous as BSG % increases. The regression analysis indicates that the quadratic model effectively describes the relationships between the three factors and each of the most important properties of the films; it is suitable for predicting film behavior and optimizing their characteristics depending on the desired use.