Design and validation of antibacterial and pH response of cationic guar gum film by combining hydroxyethyl cellulose and red cabbage pigment.

A simple and feasible method was adopted to construct the antibacterial and pH response of cationic guar gum (CGG) composite films (CGG-HEC, RC) through using hydroxyethyl cellulose (HEC) as an enhancer and red cabbage (RC) as a smart active substance. The effect of different HEC content on the binary composite films (CGG-HEC) performance shows that the highest tensile strength (51.59 MPa) can be obtained by adding 10% HEC due to the good compatibility between CGG and HEC. The ternary composite film (RC3) with 10% HEC and 3% RC addition has good performance in all aspects, such as high tensile strength (65.41 MPa), appropriate water vapor transmission coefficient (1.08), and good thermodynamic stability. In addition, RC3 has good antibacterial properties against E. coli and Staphylococcus aureus, taking advantage of the antibacterial properties of CGG and RC. RC3 can respond to changes in environmental pH and has a significant color change, and also has a significant color change when detecting the deterioration of pork and soy milk. Therefore, the ternary composite film (RC3) has good mechanical properties, antibacterial and intelligent response characteristics, and may be used in intelligent antibacterial packaging.