Wet-heating induced Maillard reaction between abalone protein hydrolysates and pectin with degree of methoxylation:...

Low-methoxyl and high-methoxyl pectins were incorporated into abalone protein hydrolysates (APH) through physical mixing or Maillard reaction to form colloidal particles. The effects of degrees of methoxylation of pectin and the preparation methods of complexes were studied on the structural modifications and functional properties of APH. The results showed that glycation with high-methoxyl pectin (HP) decreased α-helix content to 11% and increased β-sheet content to 36%, accompanied by a marked enhancement in intrinsic fluorescence. Concurrent increases in surface hydrophobicity and hydrogen-bond network reconfiguration produced more flexible, amphiphilic protein-polysaccharide conjugates. Low-methoxyl pectin (LP) mainly improved APH solubility and dispersibility via electrostatic modulation, whereas HP promoted wettability through hydrophobic interactions. These structural modifications led to substantial improvements in emulsifying activity, emulsion stability, foaming capacity, foam stability, and oil-holding capacity, with the APH-HP-C conjugate exhibiting the most significant enhancement in functional properties. The findings demonstrate that by selecting the degree of methoxylation of pectin and controlling the preparation method of the complexes, the functionality of APH can be tailored, thereby providing practical design principles for modifying marine-derived proteins for high-quality nutritional food applications.