Impact of dextran conjugation on physicochemical and gelling properties of sweet potato protein through Maillard reaction

Covalently linked sweet potato protein (SPP)-dextran conjugates were produced through Maillard reaction, and the effects of this conjugation on physicochemical and gelling properties of SPP were studied. Formation of SPP-dextran-conjugated product was confirmed with increase in browning intensity and molecular weight, with concomitant reduction in free amino group content of the protein. Dry-heating period of 0, 1, 3, 5 and 7 days gave rise to 0%, 12.8%, 19.0%, 25.2% and 22.8% degree of conjugation (DC), respectively. High molecular weight protein polymer with polydispersed band above 50 kDa was formed. FTIR spectroscopic analysis showed that the C-O (amide I) and C-N (amide II) stretching bands were modified by the Maillard reaction. Conjugation of SPP with dextran reduced its denaturation temperature. SPP-dextran conjugate gels' network structures were sustained by both physical interactions and covalent bonds. SPP-dextran conjugates' gels had significantly improved hardness and resilience in comparison with the unmodified SPP (P< 0.05).