NON-THERMAL TECHNOLOGIES FOR IMPROVE CHITOSAN EXTRACTION FROM SEAFOOD BY-PRODUCTS

The seafood processing industry generates large volumes of crustacean by-products that are commonly underutilized despite being rich in chitin, a valuable biopolymer that can be converted into chitosan for several applications. This study aimed to optimize the recovery of high-quality chitosan from crustacean by-products by integrating conventional extraction with innovative non-thermal technologies. Initially, by-products from different shrimp species were processed using an optimized thermochemical extraction method. Among the evaluated raw materials, Squilla mantis exhibited the highest chitosan yield (20.25%) and was selected for further investigation. The extracted biopolymer showed comparable or superior quality to commercial chitosan, presenting a higher degree of deacetylation (85.76%), high molecular weight (1859 kDa), whiteness index (88.07%), water holding capacity (828.86%), oil holding capacity (688.97%), and improved thermal stability. To further enhance process sustainability, pulsed electric fields (PEF), high hydrostatic pressure (HHP), and ultrasound (US) were evaluated as pretreatment technologies. PEF did not significantly affect extraction yield, whereas HHP increased chitosan recovery, reaching 20.66% at 500 MPa. The highest extraction efficiency was obtained using ultrasound-assisted extraction during the deproteinization step, achieving a chitosan yield of 24.91%, approximately 23% higher than the conventional process. Moreover, ultrasound reduced extraction time and alkali consumption while maintaining or improving the physicochemical and functional properties of the extracted biopolymer. Overall, ultrasound-assisted extraction proved to be the most promising strategy for pilot-scale implementation, combining higher extraction efficiency, lower environmental impact, and economic feasibility. These findings highlight the potential of combining conventional extraction with non-thermal technologies to transform crustacean by-products into high-value chitosan, providing an innovative approach for enhanced seafood by-products valorization within circular bioeconomy strategies.