Films were made by blending either unripe banana or rice flour with sodium montmorillonite (MMT) by means of the casting method. Structural characterization by X-ray diffraction was performed to explain the interactions of the components between MMT and flour components. The effects of storage time on structure and mechanical properties of the films by X-ray diffraction, tensile at break and elongation were evaluated. Storage of the films produced reorganization of starch components (amylose and amylopectin). Addition of MMT modified the reorganization process, which was observed by X-ray diffraction pattern and mechanical properties of the films. Reorganization process was affected by flour type due to that starch present in those flours has different structural characteristics (e.g., granule size).