A pH and NH3 sensing intelligent film based on Artemisia sphaerocephala Krasch gum and red cabbage anthocyanins anchored by carboxymethyl cellulose sodium added as a host complex

The aim of this work was to prepare an intelligent Artemisia sphaerocephala Krasch. gum (ASKG)-based film capable of anchoring the natural dye extracted from red cabbage (RCA). For this purpose, carboxymethyl cellulose sodium (CMC center dot Na) was selected as a host complex. Zeta-potential, Fourier-transform infrared spectroscopy, X-ray diffraction, rheology, and release results revealed that RCA interacted with CMC center dot Na through electrostatic interactions and altered the complicated spatial structure and crystal structure between ASKG and CMC center dot Na. The tensile strength, light-transmission and transparency of the films decreased after adding RCA, while elongation at break and water-vapor permeability increased. The RCA solution exhibited a color change from pink to green along with pH variations ranging from 3.0 to 10.0. Additionally, the RCA-containing ASKG/CMC center dot Na-blended films responded to buffer solutions (from rose-bengal to aquamarine) and NH3 (from yellow-green to yellow). The films containing RCA content > 5% were more suitable for practical applications, because they are detectable by the human eye over a wide pH range. These results indicated that RCA-containing ASKG/CMC center dot Na-blended films exhibited potential as intelligent packaging and gas-sensing labels.