Tailoring chitosan from black soldier fly waste: Impact of deacetylation degree on physicochemical properties and active packaging potential

The upcycling of agro-industrial waste presents a sustainable approach to reducing waste and creating valued biomaterials. In this study, chitin was extracted from Black Soldier Fly (BSF) shells, as a major byproduct of alternative protein production, using two protocols: a conventional method with organic solvents and an organic solvent-free method employing sodium hypochlorite-based depigmentation. Chitin was transformed into chitosan with a controlled degree of deacetylation (DDA) to tailor material properties using freeze–thaw-assisted process. Varying DDA between 9% and 83% enabled a systematic investigation of DDA's influence on physicochemical properties of chitosan such as solubility, rheology, thermal stability, and film-forming ability. The performance of BSF chitosan as packaging material for food preservation was examined on proof-of-concept set up using fresh-cut pumpkin model. BSF chitosan demonstrated improved antimicrobial activity and food's color preservation compared to crustacean chitosan and polyester-based commercial package Topaz B-235. By day 5, aerobic counts of fresh-cut pumpkin stored in BSF chitosan reached 0.9 log CFU/g compared to 4.2 log CFU/g in crustacean chitosan and 6.6 log CFU/g in Topaz B-235, while fungal/yeast counts reached 0.9 log CFU/g versus 3.1 and 6.2 log CFU/g, respectively. Overall, the results highlight the feasibility of producing chitosan from BSF waste and its promise as a sustainable packaging material. • Chitin/chitosan from waste of alternative protein industry black fly soldier (BSF) • Chitin/chitosan were produced by sustainable method without organic solvents • Tuning deacetylation degree led to series of materials with controlled properties • BSF-derived chitosan was applied as active package of fresh-cut pumpkin • BSF chitosan overcame crustacean chitosan by ∼3.3 log CFU/g in antimicrobial protection