Effect of Glycosylation on the Physicochemical Properties, Structure and Iron Bioavailability of Ferritin Extracted from Tegillarca granosa

Iron deficiency anemia (IDA) is a major global health problem. Tegillarca granosa has been considered as an excellent source of iron given its high content of iron-binding protein, ferritin. The aim of the present study was to determine the physicochemical properties, protein structures, and iron uptake of ferritin extracted from T. granosa , and to evaluate the potential impacts of chitosan glycosylation on these characteristics. Based on Box-Behnken design and response surface methodology, the optimal conditions for glycosylation included a ferritin/chitosan mass ratio of 4:1, a pH of 5.5, a reaction time of 10 min, and a reaction temperature of 50 °C. Glycosylation caused decreased surface hydrophobicity and elevated water-holding capacity of ferritin due to the introduction of hydrophilic groups. Additionally, glycosylation improved antioxidant capacity of ferritin by 20.69%–189.66%, likely owing to the protons donated by saccharide moiety to terminate free radical chain reaction. The in vitro digestibility of ferritin was elevated by 22.56%–104.85% after glycosylation, which could be associated with less β-sheet content in secondary structure that made the glycosylated protein less resistant to enzymatic digestion. The results of the iron bioavailability in Caco-2 cells revealed that ferritin (78.85–231.77ng mg −1 ) exhibited better iron bioavailability than FeSO 4 (51.48–114.37 ng mg −1 ) and the values were further elevated by glycosylation with chitosan (296.23–358.20 ng mg −1 ), which may be related to the physicochemical properties of ferritin via glycosylation modification. These results provide a basis for the development of T. granosa derived ferritin and its glycosylated products, and can promote the utilization of aquatic resources.