Kokumi Taste Active Peptides Modulate Salt and Umami Taste.

Mee-Ra Rhyu,Yiseul Kim,Shobha Mummalaneni,Vijay Lyall,Jie Qian,Hee-Jin Son,Eun-Young Kim,Ah-Young Song,John R Grider

doi:10.3390/nu12041198

Abstract

Kokumi taste substances exemplified by γ-glutamyl peptides and Maillard Peptides modulate salt and umami tastes. However, the underlying mechanism for their action has not been delineated. Here, we investigated the effects of a kokumi taste active and inactive peptide fraction (500–10,000 Da) isolated from mature (FIIm) and immature (FIIim) Ganjang, a typical Korean soy sauce, on salt and umami taste responses in humans and rodents. Only FIIm (0.1–1.0%) produced a biphasic effect in rat chorda tympani (CT) taste nerve responses to lingual stimulation with 100 mM NaCl + 5 μM benzamil, a specific epithelial Na+ channel blocker. Both elevated temperature (42 °C) and FIIm produced synergistic effects on the NaCl + benzamil CT response. At 0.5% FIIm produced the maximum increase in rat CT response to NaCl + benzamil, and enhanced salt taste intensity in human subjects. At 2.5% FIIm enhanced rat CT response to glutamate that was equivalent to the enhancement observed with 1 mM IMP. In human subjects, 0.3% FIIm produced enhancement of umami taste. These results suggest that FIIm modulates amiloride-insensitive salt taste and umami taste at different concentration ranges in rats and humans.

Highlights

Mammals use G-protein-coupled receptors (GPCRs) expressed in Type II taste receptor cells (TRCs) to detect bitter, sweet, and umami taste stimuli
Much progress has been made in the identification of taste receptors and the downstream signalling mechanisms involved in the transduction of salty, sour, sweet, bitter and umami taste qualities
FIIm produced concentration-dependent biphasic effects on salt taste perception and at higher concentrations enhanced umami taste. These results suggest that FIIm modulates salty and umami taste in rodents and humans via similar mechanisms

Summary

Introduction

Mammals use G-protein-coupled receptors (GPCRs) expressed in Type II taste receptor cells (TRCs) to detect bitter, sweet, and umami taste stimuli. While amiloride-sensitive salt taste is detected by Type. 1 cells expressing epithelial Na+ channels, Type II and Type III cells mediate amiloride-insensitive salt taste. Otopetrin-1 proton selective channel expressed in Type III TRCs detects sour taste stimuli [1,2,3,4,5,6]. Much progress has been made in the identification of taste receptors and the downstream signalling mechanisms involved in the transduction of salty, sour, sweet, bitter and umami taste qualities. Umami peptides modulate bitterness by interfering with ligand binding to the human bitter taste receptor TAS2R16 [11]. Interactions between non-tastants and tastants can modulate taste intensity

Methods

Results

Conclusion