Mitigating the adverse effect of pH on stability and antioxidant activity of phycocyanin via nanohydrogel encapsulation

Phycocyanin (PC) holds significant potential for application in food production and biomedicine. Nevertheless, the stability and antioxidant activity of PC are influenced by pH. Improving the stability of PC under various pH conditions is thus highly demanded. Herein, N-isopropyl acrylamide (NIPAM) and chitosan were used to prepare poly(NIPAM-co-chitosan) (PNC) nanohydrogels for encapsulation PC, aiming to mitigate the adverse effect of pH on the stability and antioxidant activity of PC. The stability and antioxidative activity of PC encapsulated in PNC nanogels were evaluated at different pH values by determining the pigment retention rate (PRR) and free radical scavenging ability, respectively. The results demonstrated that the PNC encapsulation improved the stability and antioxidant activity of PC.