Structural Feature\nof Salty/Saltiness-Enhancing Peptides\nDerived from <i>Coprinus comatus</i> and Their Stability\nduring Subsequent Thermal Treatment and Maillard Reaction

Through\na quantitative analysis of saltiness perception, favorable\nenzymatic hydrolysis parameters were confirmed for the preparation\nof saltiness-enhancing peptide mixtures from Coprinus\ncomatus. The enzymatic hydrolysate was fractionated\ninto four fractions (F1–F4) by gel chromatography, with F3\nexhibiting the strongest saltiness-enhancing effect (22% increase).\nLC-MS/MS analysis of F3 identified 36 peptides, and their secondary\nstructures and interactions with the TMC4 receptor were examined through\ncircular dichroism spectroscopy and molecular docking. Molecular docking\nanalysis revealed Asn588, Ser165, Asp5, and Arg168 as key amino acid\nresidues, with the peptide GDNVGF showing the lowest binding energy.\nSynthetic GDNVGF (0.01%) in 70 mmol/L NaCl enhanced saltiness by 17%.\nWhen 0.7% GDNVGF was added to the aqueous solution, its saltiness\nwas equivalent to that of 36.89 mmol/L NaCl, which suggested that\nGDNVGF functions both as a saltiness-enhancing peptide and a salty\npeptide. The taste changes of peptides during thermal reactions were\nfurther investigated. The thermal stability of <i>Coprinus comatus</i> peptides was good, but\ntheir saltiness-enhancing effect slightly reduced due to thermal degradation.\nThe Maillard reaction further diminished this effect, though the umami\nlevel remained satisfactory, offering new insights into using <i>Coprinus comatus</i> peptides\nas low-sodium salt substitutes.