Effects of cassia gum and konjac glucomannan on the structural and functional properties of Maillard-modified fungal protein concentrate from Mucor

Wet-heating Maillard conjugation improved FPC solubility and stability. • CG and KGM induced distinct structural changes in Mucor FPC. • FPC-CG showed greater functional improvement than FPC-KGM. • The 20:3 FPC/polysaccharide ratio gave the best overall performance. Fungal protein concentrate (FPC) is a promising sustainable protein ingredient, but its poor solubility and limited interfacial stability restrict its food applications. In this study, Mucor-derived FPC was conjugated with cassia gum (CG) or konjac glucomannan (KGM) by wet-heating Maillard reaction at different mass ratios. Compared with native FPC and physical-mixture controls, both conjugates showed evident structural modification and improved functionality, with the best overall performance at an FPC/polysaccharide ratio of 20:3. At this ratio, the degree of glycation reached 38.86% for FPC-CG and 29.62% for FPC-KGM, while surface hydrophobicity decreased from 254.68 to 146.11 and 179.43, respectively. Intrinsic fluorescence showed red shifts from 315 nm to 318 nm (FPC-CG) and 319 nm (FPC-KGM), and ordered secondary structure decreased by 12.20% and 10.54%, respectively. These structural changes were associated with enhanced solubility, emulsifying properties, foam stability, water- and oil-holding capacities, and DPPH radical-scavenging activity. Overall, CG produced stronger improvements than KGM, indicating that polysaccharide structure is critical for designing functional fungal protein-polysaccharide conjugates.