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Results for “Umami peptides”

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13 recordsLinked to original sources

PubMed1999

Effect of the umami peptides on the ligand binding and function of rat mGlu4a receptor might implicate this receptor in the monosodium glutamate taste transduction.

1. The effect of several metabotropic ligands and di- or tripeptides were tested on the binding of [3H]-L(+)-2-amino-4-phosphonobutyric acid ([3H]-L-AP4) on rat mGlu4 receptor. For selected compounds, the functional activity was determined on this receptor using the guanosine-5'[gamma-35S]-thiotriphosphate [gamma-35S]-GTP binding assay. 2. Using the scintillation proximity assay, [3H]-L-AP4 saturation analysis gave binding parameters K(D) and Bmax values of 150 nM and 9.3 pmoles mg-1 protein, respectively. The specific binding was inhibited concentration-dependently by several mGlu receptor ligands, and their rank order of affinity was established. 3. Several peptides inhibited the [3H]-L-AP4 binding with the following rank order of potency: glutamate-glutamate>glutamate-glutamate-leucine=aspartate - glutamate>>glutamate - glutamate-aspartate>lactoyl-glutamate>>aspartate-aspartate. Aspartate-phenylalanine-methyl ester (aspartame) was inactive up to 1 mM and guanosine-5'-monophosphate and inosine-5'-monophosphate were inactive up to 100 micronM. 4. The [gamma-35S]-GTP binding functional assay was used to determine the agonist activities of the different compounds. For the rat mGlu4 agonists, L-AP4 and L-glutamate, the correlation between their occupancy and activation of the receptor was close to one. The peptides, Glu-Glu, Asp-Glu and Glu-Glu-Asp failed to stimulate the [gamma-35S]-GTP binding at receptor occupancy greater than 80% and Glu-Glu-Leu appeared to be a weak partial agonist. These peptides did not elicit a clear dose-dependent umami perception. However, Glu-lac showed a good correlation between its potency to stimulate the [gamma-35S]-GTP binding and its affinity for displacement of [3H]-L-AP4 binding. These data are in agreement with the peptide taste assessment in human subjects, which showed that the acid derivatives of glutamate had characteristics similar to umami.

Adult↗

PubMed2026

Molecular mechanisms underlying umami taste perception: A DIA-based proteomic analysis of Agrocybe aegerita peptides.

The mechanisms underlying the modulation of the salivary perception of umami peptides remain poorly understood. Herein, three umami peptides (DDL, DEL, and ENG) obtained from Agrocybe aegerita were used to investigate the regulatory role of saliva in umami taste perception via a combined approach involving sensory evaluation and proteomics analysis based on 4D-DIA technology. The results revealed that umami intensity peaked at 10 s after ingestion and was accompanied by a significant increase in saliva secretion (p < 0.05). Further proteomics analysis revealed that lactotransferrin and proline-rich proteins are closely associated with the sensory perception of umami peptides. Differentially expressed proteins were mainly enriched in pathways related to saliva secretion and proteasome function. This study provides new insights from the perspectives of salivary proteomics and dynamic salivary secretion, contributing to a deeper understanding of the mechanisms by which saliva regulates umami perception.

Humans↗

PubMed1999

Isolation of peptides from an enzymatic hydrolysate of food proteins and characterization of their taste properties.

Soybean protein, casein, bonito protein and chicken protein, each as foodstuff protein, were hydrolyzed with four proteinases; namely, pepsin, trypsin, alpha-chymotrypsin and bromelain. Since the chicken protein hydrolysate with bromelain possessed the most favorable umami taste, eleven peptides were isolated from the chicken protein hydrolysate by successive chromatography on ODS, Amberlite IR-120B, Amberlite IRA-410 and AG-50W; their structures were Asp-Ala, Asp-Val, Glu-Glu, Glu-Val, Ala-Asp-Glu, Ala-Glu-Asp, Asp-Glu-Glu, Asp-Glu-Ser, Glu-Glu-Asn, Ser-Pro-Glu, and Glu-Pro-Ala-Asp. Many of them did not show any umami taste by themselves, but Glu-Glu, Glu-Val, Ala-Asp-Glu, Ala-Glu-Asp, Asp-Glu-Glu, and Ser-Pro-Glu were recognized to enhance the umami taste of 0.02% 5'-inosine monophosphate (IMP). A combination of these peptides, especially 0.5% each of Glu-Glu, Glu-Val, Asp-Glu-Glu and Glu-Glu-Asn, with 0.02% IMP produced a delicious "full" umami taste.

Animals↗

PubMed2004

Sourness-suppressing peptides in cooked pork loins.

This study was conducted to identify the sourness-suppressing peptides in cooked pork and to clarify the mechanism of sour taste suppression by the peptides. An extract prepared from pork loins vacuum-cooked at 60 degrees C for 6 hours after conditioning at 4 degrees C for 20 days was separated into three fractions: under MW 500 (Fraction I), MW 500-1,000 (Fraction II), and over MW 1,000 (Fraction III). The Fraction I content was largest. As judged by sensory evaluation, the addition of Fraction II was capable of suppressing stronger sourness than the other fractions. Fraction II also enhanced umami and saltiness. Three peptides (APPPPAEVHEVV, APPPPAEVHEVVE, and APPPPAEVHEVHEEVH) in Fraction II increased greatly during conditioning. A common peptide, APPPPAEVHEV, in the amino acid sequences of the three peptides suppressed the sour taste. The mechanism of sourness suppression by the peptide was concluded to comprise inhibition of the binding of sour taste substances to the membranes of the tongue.

Amino Acid Sequence↗

PubMed1995

Role of basic and acidic fragments in delicious peptides (Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala) and the taste behavior of sodium and potassium salts in acidic oligopeptides.

The role of the acidic fragment (Asp-Glu-Glu) in delicious peptides was investigated in detail by using the Na+ or K+ salts of acidic oligopeptides so that amount of Na+ or K+ intake of peptides composed of acidic amino acids could be varied by changing their sequences. The taste of these peptides was confirmed to vary with Na+ or K+ intake. Additionally, in order to study the role of basic (Lys-Gly) and acidic (Asp-Glu-Glu) fragments in delicious peptides for producing the taste, five delicious peptide analogs, Ser-Leu-Ala-Lys-Gly-Asp-Glu-Glu, Ser-Leu-Ala-Asp-Glu-Glu-Lys-Gly, Lys-Gly-Ser-Leu-Ala-Asp-Glu-Glu, Lys-Gly-Asp-Glu-Glu, and Glu-Glu-Asp-Gly-Lys, were synthesized. The intensity of the umami and/or salty taste of these peptides and their Na salts was almost the same, despite their chemical structures being different. These results indicate that the acidic fragment as well as the basic fragment plays an important role in the taste production and intensity of delicious peptides, and that an umami or salty taste can be produced by the localization of the cation of the basic fragment and the anion of the acidic fragment.

Amino Acid Sequence↗

PubMed2001

Determination of taste-active compounds of a bitter Camembert cheese by omission tests.

The taste-active compounds of a Camembert cheese selected for its intense bitterness defect were investigated. The water-soluble fraction (WSE) was extracted with pure water and fractionated by successive tangential ultrafiltrations and nanofiltration. The physicochemical assessment of these fractions led to the construction of a model WSE which was compared by sensory evaluation to the crude water-soluble extract, using a panel of 16 trained tasters. As no significant difference was perceived, this model WSE was then used directly or mixed with other cheese components for omission tests. Among the main taste characteristics of the WSE (salty, sour, umami and bitter), bitterness was found to be due to small peptides whose mass distribution was obtained by RPHPLC-MS (400-3000 Da) and whose taste properties are discussed.

Amino Acids↗

PubMed1996

Tastes produced by peptides containing ionic groups and by related compounds.

The typical tastes imparted by ionic groups are salty-like of sodium chloride and umami-like of monosodium glutamate, but the relationship between the taste and chemical structure has not previously been elucidated. One of the reason for the difficulty in understanding the taste-structure relationship is the presence of the ambiguous and unfavorable tastes of neutral salts. We define the strange tastes of neutral salts (TNS) collectively in a specific category, and then the tastes due to ionic groups. Sour, salty, and umami tastes and TNS were studied for different acidic and basic groups and various combinations of both groups to elucidate the taste characteristics of the ionic groups. The results reveal that the tastes due to ionic groups have common characteristics, being different from bitter and sweet tastes.

Alkalies↗

PubMed2006

Elucidation of the role of peptide linker in calcium-sensing receptor activation process.

Family 3 G-protein-coupled receptors (GPCRs), which includes metabotropic glutamate receptors (mGluRs), sweet and "umami" taste receptors (T1Rs), and the extracellular calcium-sensing receptor (CaR), represent a distinct group among the superfamily of GPCRs characterized by large amino-terminal extracellular ligand-binding domains (ECD) with homology to bacterial periplasmic amino acid-binding proteins that are responsible for signal detection and receptor activation through as yet unresolved mechanism(s) via the seven-transmembrane helical domain (7TMD) common to all GPCRs. To address the mechanism(s) by which ligand-induced conformational changes are conveyed from the ECD to the 7TMD for G-protein activation, we altered the length and composition of a 14-amino acid linker segment common to all family 3 GPCRs except GABA(B) receptor, in the CaR by insertion, deletion, and site-directed mutagenesis of specific highly conserved residues. Small alterations in the length and composition of the linker impaired cell surface expression and abrogated signaling of the chimeric receptors. The exchange of nine amino acids within the linker of CaR with the homologous sequence of mGluR1, however, preserved receptor function. Ala substitution for the four highly conserved residues within this amino acid sequence identified a Leu at position 606 of the CaR critical for cell surface expression and signaling. Substitution of Leu(606) for Ala resulted in impaired cell surface expression. However, Ile and Val substitutions displayed strong activating phenotypes. Disruption of the linker by insertion of nine amino acids of a random-coiled structure uncoupled the ECD from regulating the 7TMD. These data are consistent with a model of receptor activation in which the peptide linker, and particularly Leu(606), provides a critical interaction for the CaR signal transmission, a finding likely to be relevant for all family 3 GPCRs containing this conserved motif.

Amino Acid Motifs↗

PubMed1997

Flavor characteristics of glutathione in raw and cooked foodstuffs.

The flavor of glutathione (gamma-L-glutamyl-L-cysteinylglycine, GSH) was examined by several sensory evaluations. The measurement of a point of subjective equality (PSE) showed that the peptide increases the flavor characteristics but did not affect the intensity of basic tastes, such as sweetness, saltiness, sourness, and umami. However, the threshold value of GSH decreased significantly in an umami solution containing 0.05% each of monosodium glutamate (MSG) and disodium inosinate (IMP). This suggests that GSH interacts with the umami substance and has a certain effect on the flavor. GSH had a characteristic kokumi flavor, such as continuity, mouthfulness, and thickness in the umami solution as well as in a model beef extract constructed from analyzed components at a concentration of 0.02% w/v. Some foodstuffs, including meat, were found to contain GSH above its threshold value, which implicates the contribution of GSH to the flavor. The thermal degradation study suggested that a part of GSH have changed into its disulfide, pyroglutamic acid (PCA), and cyclocysteinylglycine in cooked foodstuffs.

Cooking↗

PubMed2001

Behavioral taste similarities and differences among monosodium L-glutamate and glutamate receptor agonists in C57BL mice.

Monosodium L-glutamate (MSG) and 5'-ribonucleotides elicit umami taste in humans and probably in some species of animals. Previous studies suggest that taste-mGluR4 and NMDA receptor may be involved in taste transduction for umami, but behavioral responses in rats do not support the involvement of NMDA receptor. In the present study, behavioral similarities and differences among MSG, mGluR4 agonist L(+)-2-amino-4-phosphonobutyrate (L-AP4), and NMDA receptor agonist N-methyl-D-aspartate (NMDA) were compared in C57BL mice by using a conditioned taste aversion paradigm. Mice conditioned to avoid either MSG or 10 mM L-AP4 appeared to avoid MSG, disodium 5'-inosinate (IMP), a mixture of MSG and IMP, and L-AP4, but not NMDA. Aversive conditioning to either sucrose or NMDA was generalized only to a mixture of MSG+IMP or NaCl. However, aversive conditioning to L-AP4 at 1 mM was generalized to NMDA and the umami substances. Lick rates for L-AP4 increased by mixing with (RS)-alpha-cycloprophy-4-phosphonophenylglycine (mGluR4 antagonist) when animals were conditioned to avoid MSG or L-AP4. Lick rates for NMDA also either decreased or increased by mixing with glycine (NMDA receptor coagonist) or D(-)-2-amino-5-phosphonopentanoic acid (NMDA receptor antagonist) when animals were conditioned to avoid L-AP4 or NMDA. In sucrose-conditioned mice. gurmarin (a sweet inhibiting peptide) suppressed the avoidance of sucrose and a mixture of MSG and IMP, but not L-AP4 and NMDA. The results suggest the possibility that to C 57BL mice MSG may taste similar to L-AP4 but different from NMDA, although both types of glutamate receptors as well as gurmarin-sensitive sweet receptor may be involved in perception of umami taste.

Animals↗

PubMed1999

Analyses of taste nerve responses with special reference to possible receptor mechanisms of umami taste in the rat.

Umami substances such as monopotassium L-glutamate (MPG) and 5'-inosine monophosphate (IMP) elicit a unique taste called 'umami' in humans. To elucidate the umami receptor mechanism in rats, we examined taste responses of the chorda tympani nerve by using three ionotropic glutamate receptor agonists, NMDA, KA and AMPA, a mGluR4 agonist, L-AP4, and a specific mGluR4 antagonist, MAP4, and an anti-sweet peptide, gurmarin. When IMP was added, synergistic responses were shown only for MPG and L-AP4, but not for NMDA, KA and AMPA. MAP4 enhanced the responses to MPG and L-AP4. Gurmarin suppressed the synergistic responses to mixtures of MPG and IMP or L-AP4 and IMP. These results suggest that glutamate and L-AP4 bind both the sweet-responsive macromolecule and mGluR4, but the synergism occurs only on the macromolecule.

Animals↗

PubMed2006

Proteomic analysis of human whole and parotid salivas following stimulation by different tastes.

Whole and parotid salivas, collected after stimulation with tastants, were analyzed by 2D electrophoresis and mass spectrometry. In whole saliva, the number of proteins affected by taste stimulation increased in the order sweet < umami < bitter < acid. Annexin A1 and calgranulin A, involved in inflammation, were over-represented after umami, bitter, and sour stimulations. Their low abundance or absence in parotid saliva after bitter stimulation suggested that they originated from other oral glands or tissues.

Annexin A1↗

PubMed2002

Analysis of taste-active compounds in an enzymatic hydrolysate of deamidated wheat gluten.

Hydrolyzed plant proteins are widely used as ingredients in culinary products for their glutamate-like ("umami") taste. Three hydrolysates were prepared from wheat gluten using different enzymatic approaches. Comparison of their taste profiles revealed the enzymatic hydrolysate of an acid-deamidated wheat gluten (WGH-3) to be the least bitter of all and to elicit an intense glutamate-like taste. Its umami taste intensity was similar to that of an enzymatic hydrolysate in which glutaminase had been employed to convert free glutamine to glutamic acid and which had a 3-fold higher concentration of free glutamate. Reconstitution studies based on the results of the chemical analysis of WGH-3 and sensory comparison of the model solution and WGH-3 indicated that other components in addition to glutamate and organic acids contribute to its glutamate-like taste. WGH-3 was fractionated by gel permeation chromatography and reversed phase high-performance liquid chromatography, and two fractions with a pronounced glutamate-like taste were obtained. In one of them four pyroglutamyl peptides were tentatively identified: pGlu-Pro-Ser, pGlu-Pro, pGlu-Pro-Glu, and pGlu-Pro-Gln. Apparently, these peptides were formed by cyclization of the N-terminal glutamine residues during the preparation of the hydrolysates.

Adult↗