The objective of this study was to produce new active and intelligent high performance colorimetric films based on cellulose acetate (CA), and to evaluate the synergistic effect of thymol (THY) and anthocyanin (ANT). The colour films showed significant reactivity to pH change, and the films became thicker in the presence of glycerol (0.200 +/- 0.05). FTIR and SEM images showed a homogeneous distribution and new interactions created between THY, ANT and CA, which modified the thermal properties. This behaviour was also confirmed by XRD analysis, which showed a reduction in film crystallinity with increasing anthocyanin concentration. In addition, the incorporation of ANT improved the mechanical properties by reducing the tensile strength (0.075 +/- 0.021 MPa), the biodegradability of the films in the soil after 60 days and also the water vapor transmission rate (14.81 g mm-2 h-1). The films showed synergistic antibacterial activity and the application trials showed colour changes that were highly visible to the naked eye, with the deterioration of the fish, suggesting a promising application for these films as an indicator of fish freshness.

Intelligent packaging film has received more and more attention because it can help consumers obtain more intuitive information about the packaging, provide better preservation and advanced convenience. In this study, black rice anthocyanin (BRA) was added into composite film formed by starch (S) and esterified starch (ES). As the BRA content increased, the thickness and the total color difference of the S/ES-BRA film increased. The opacity of S/ES-BRA film decreased relative to that of the film without BRA, but increased with the increase of anthocyanin. Compared with S/ES film, the elongation at break of S/ES-BRA0.5 film increased from 33.1 % to 45.4 %, and the tensile strength decreased from 7.3 to 5.8 MPa. S/ES-BRA film had response to different pH values and underwent color changes in different buffer solutions. Intelligent color changing packaging film will used to monitor food quality, water quality and soil properties.