Pectin/sodium alginate-based active film integrated with microcrystalline cellulose and geraniol for food packaging applications

Biopolymer-based packaging films were prepared from pectin (PEC) and sodium alginate (SA), with the incorporation of 10 % MCC and different concentrations of geraniol (GER at 2.5, 5.0, 7.5, and 10.0 %). Rheological properties suggested that film-forming solutions and film-forming emulsions exhibited a shear-thinning or pseudo-plastic non-Newtonian behaviour. The dried films were crosslinked with 2.0 % CaCl₂. The addition of MCC into PEC/SA film enhanced the TS but reduced it with the impregnation of GER without influencing the EAB and toughness of the film. The water solubility of the films significantly reduced with the rise in the GER levels but enhanced the water vapor and oxygen barrier attributes. TGA demonstrated that incorporating MCC reduced the film's thermal degradation (44.92 % to 28.81 %), but GER had an insignificant influence on the thermal stability. FTIR spectra revealed that hydrogen bond formation was positively linked with the GER addition in the film formulation. X-ray diffractograms showed that prepared films were predominantly amorphous. Antimicrobial studies showed a complete reduction of Escherichia coli and Bacillus cereus in 24 h. Overall, the composite film displayed excellent physical and active properties and PEC/SA/MCC/5.0 %GER/CaCl₂ film was considered the best formulation for food packaging applications.