Abstract
This study aimed to encapsulate shrimp head protein hydrolysate (SPH) derived from Litopenaeus vannamei using composite alginate/chitosan hydrogels for potential food applications. SPH-loaded microparticles were produced via ionic gelation of 3% (w/v) alginate and 0.25% (w/v) chitosan in the presence of calcium lactate, achieving the highest encapsulation efficiency of 61% and an average diameter of ~1.5 mm. These beads exhibited pH-responsive behavior during in vitro digestion. They could withstand gastric conditions and showed a burst protein release of > 72% upon transition to the intestinal phase, resulting in ~95% recovery of SPH in simulated small intestinal fluid. Air-drying at 50°C for 18 h preserved both the structural integrity of the beads and the bioactivities of encapsulated SPH, making it a viable strategy for prolonging the beads' shelf-life. Air-dried beads (~4% moisture content) possessed swelling capacity and stability at both acidic and alkali pH levels, but disintegrated rapidly at pH 7.0. Antioxidant, anti-hypertensive, and anti-obesity activities of the encapsulated SPH were significantly better maintained over 4 weeks of refrigeration compared to its non-encapsulated counterpart, highlighting the protective role of the alginate/chitosan matrix during storage of the beads. These results support the valorization of shrimp-processing wastes as a source of functional ingredients for incorporation into food and pharmaceutical products. Future research should focus on characterizing the bioactive peptide profiles of SPH and elucidating their interactions within encapsulation matrices. In vivo studies are also needed to validate the current findings and inform the rational design of targeted delivery systems for specific food-related applications.