Valorization of agricultural residues in the development of biodegradable active packaging films

Abstract

The demand for sustainable and biodegradable packaging has urged the use of agricultural wastes in food packaging. Agricultural residues are good and cheap sources of biopolymers which are the major materials required for development of biodegradable films. These residues are generally subjected to the extraction of biopolymers which are further utilized for the preparation of biodegradable films. In the present research, orange peels were directly utilized for the development of biodegradable packaging films. Wheat straw and rice husk in different concentrations (i.e. 0%, 3%, 6%, 9% and 12%) were used as reinforcement material/filler in orange peel films. The effect of fillers on mechanical (thickness, tensile strength & elongation at break), structural (FTIR, SEM), optical, water barrier (WVP, water solubility, swelling index) active (DPPH antioxidant and antimicrobial activity) and biodegradation properties was evaluated. The results reported a significant increase in thickness, tensile strength and opacity in reinforced films compared to native orange peel films. However, the tensile properties increased upto 6% and decreased above this concentration due to agglomeration of filler particles in film matrix. Moisture contents, swelling index, solubility, WVP, biodegradability and elongation at break decreased with increasing filler concentration. FTIR results showed physical interaction between film components and fillers. SEM results revealed that the films reinforced with wheat straw and rice husk showed rough surface. Moreover, reinforcement also improved the active properties of orange peel films. RH and WS being rich sources of bioactive compounds, significantly enhanced DPPH scavenging activity and TPC. All films showed a clear inhibition against E. coli and S. aureus.