Design, Synthesis, and Antimicrobial Activity of Biodegradable Sodium Alginate/COF Polymeric Films for Smart Monitoring of Food Spoilage and Active Food Packaging

As the human population increases very rapidly, it is necessary to develop an efficient biodegradable packaging material to increase the shelf life of food, guarantee food safety, and reduce spoilage from extreme conditions. To overcome all of these problems, herein, we synthesize smart sensing strips and antimicrobial active food packaging films to prevent molding. For smart sensing of food spoilage, covalent organic frameworks (COFs) were synthesized from 2,4,6-triformylphloroglucinol (TFP) and p-phenylenediamine. Thereafter, COF was incorporated into a sodium alginate polymeric material to obtain sensing strips with highly colorimetric response and augmented mechanical properties. Smart sensing strips were demonstrated on packaged poultry meat. The sensing strips are highly pH-responsive and color changes according to the pH of the surrounding. Sensing responses of COF were also studied for the biogenic amines that evolve during the spoilage of meat using cyclic voltammetry. The SA/COF film was characterized through different techniques including atomic force microscopy, field emission scanning electron microscopy, Brunauer-Emmett-Teller, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and powder X-ray diffraction. In addition to this antimicrobial citral was incorporated into the SA/COF film to prepare an active packaging film, which reduces food spoilage from high humidity, molding, and high-temperature conditions. The active packaging film was applied to the peanuts to avoid mold formation, which increases their shelf life and reduces food wastage. Based on the above research, we designed a polymeric film for smart sensing and packaging of food.