Identification of transmembrane channel–like 4-targeting saltiness–enhancing peptides derived from chicken skin collagen and evaluation of their antioxidant abilities

Saltiness–enhancing peptides are a novel class of salt substituents capable of partially replacing sodium chloride (NaCl) in food products. The current study describes the isolation and identification of saltiness–enhancing peptides from chicken skin collagen hydrolysate. Six of the peptides, including GERGPKGPKGETGPT (GT15), GPAGPPGARGQAG (GG13), GPPGPTGPA (GA9), GPPGPTGPAGER (GR12), VGPTGPAGPR (VR10), and VGSP (VP4), were found to enhance the saltiness intensity of a 0.35 % (w/v) solution of NaCl. These six peptides exhibited an umami taste, with GT15 and GR12 additionally having a salty taste. Molecular dynamics simulation revealed that these peptides can stably bind to the salty taste receptor transmembrane channel–like 4 via hydrogen bonds. In vitro studies revealed that these peptides exhibited antioxidant activities. These six saltiness–enhancing peptides can therefore be potentially applied for augmenting the saltiness of NaCl solution and partially replacing salt in food products while preventing the oxidative damage typically caused by high amounts of salt.