Delving the potential of quercetin-grafted chitosan from a technological and environmental perspective

The transition to a sustainable bioeconomy requires the development of advanced materials with improved functional properties, in particular bio-based products that could have a low environmental impact. Chitosan, derived from crustacean chitin, is a biodegradable biopolymer with multiple applications in the pharmaceutical, cosmetic and food sectors. Similarly, quercetin is a bio-based flavonoid extracted from plants with potent antioxidant and antimicrobial activities. However, its poor solubility, bioavailability and rapid degradation limit its use. This manuscript proposes a synergistic action for the formulation of a bioactive biopolymer based on the enzymatic oxidation of quercetin and its enzymatic grafting onto chitosan. This biopolymer protects the active ingredients from chemical, enzymatic, thermal and light degradation and increases their bioavailability. In addition, other advantages such as vectorization and controlled release are envisaged. This production scheme was modeled using the SuperPro Designer® tool to estimate operational data to be used as a Life Cycle Inventory for environmental assessment and Green Chemistry score determination. The Life Cycle Assessment (LCA) methodology was used to assess the environmental impacts, while the Greenness Grid (G2) tool allows the assessment of safety, efficiency, productivity and renewability aspects related to sustainability. The results showed that electricity is the main hotspot of the environmental profile, with an average value of 74.22 %, while the contribution of chemicals is less significant, between 15 % and 40 % of the total impact. Sensitivity analyses were proposed to improve the profile, where the use of renewable electricity represents the largest reduction of the total impact. Moreover, Monte Carlo analysis has also been developed for assessing uncertainty in the scores obtained. For the G2 tool, the final score is 11.55 out of 15, which means that the production model is in the “sustainable potential” range. • Chitosan functionalization with quercetin by grafting process. • Process modeling considering enzymatic oxidation and grafting stages. • Life Cycle Assessment of the chitosan-quercetin production scheme. • Analysis considering principles of Green Chemistry. • Potential sustainable strategy for waste valorization and functionalization.