Effect of dual-modified cassava starches on intelligent packaging films containing red cabbage extracts

This study aimed to develop intelligent packaging films possessing pH-sensitive and mechanical stability for cassava starch-based substrates using red cabbage extracts by a simple casting technique. It also investigated the effect of native and different dual-modified [oxidized hydroxypropyl starch, acetylated distarch phosphate (ADSP), and oxidized-acetylated starch] cassava starches on the morphological, physical, and pH-sensitive properties of intelligent films. Dual-modified cassava starch films presented better transparency, water-resistance, water vapor barrier ability and tensile strength than native cassava starch films. Scanning electron microscopy observation revealed the compactness of the films was improved by the modification. The addition of new groups was confirmed after the dual-modification of cassava starch in the films by infrared spectroscopy. The ADSP films had the best thermal stability compared to the other three films. Notably, all films produced intense naked-eye detectable colorimetric response to pH variation (2-12) and volatile ammonia, and exhibited different color reversibility properties. Anionic cassava starch formed stable complexes with anthocyanins through electrostatic interactions and hydrogen bonding, thus enhancing the stability of anthocyanins. Therefore, cassava starch-based films have promising potential for applications in intelligent food packaging.