Responsive Bio‐Composites from Magnesium Carbonate Filled Polycaprolactone and Curcumin‐Functionalized Cellulose Fibers

Abstract Development of responsive bio‐based and biodegradable materials is particularly important in food preservation and monitoring technologies. Although replacing conventional plastic products with sustainable alternatives is still a challenge, promising advances have been reported. In this work, the fabrication of responsive bio‐composite films from polycaprolactone (PCL) and magnesium carbonate (MgCO₃), known as food additive E504 with melt impregnation into cellulose, is reported. Cellulose fibers are stained/coated with ethanoic curcumin solutions, primarily to protect them against oxidative degradation. The films demonstrate a strong antioxidant effect against fatty and aqueous food simulants with improved oxygen gas barrier properties. Interestingly, the natural chelation of curcumin with magnesium within the composites improves the bioavailability and antioxidant potency of curcumin. Moreover, the composites show reversible color change response detectable by the naked eye in basic solutions or vapors. This response is tested by placing the composite film inside a sealed plastic container containing shrimp at room temperature, but not in direct contact. Due to spoilage, a noticeable color change in the bio‐composites is recorded. These simple, cost‐effective, non‐toxic, and paper‐like flexible bio‐composites can be fabricated on large scale and be used in diverse applications ranging from sustainable packaging to medical applications and freshness indicators.