Umami Peptides Research Articles

Isolation, taste characterization and molecular docking study of novel umami peptides from Lactarius volemus (Fr.)

This study aimed to understand the tasty flavor of wild Lactarius volemus (Fr.). The umami peptides from its aqueous extraction were purified by ultrafiltration, Sephadex G-25 gel filtration chromatography, and reversed-phase high-performance liquid chromatography. Sensory evaluation was used to identify the peptide fraction with the intense umami taste, and the peptides in the fraction were identified. Four umami peptides, namely EVAEALDAPKTT, AVLEEAQKVELK, AEDLSTLR, and KVDVDSLK, were virtually selected by molecular docking and umami taste active fragment frequency. The sensory evaluation and electronic tongue revealed that four screened peptides had umami taste features with umami identification thresholds in the range of 0.0625–0.250 mg/mL. Molecular docking results showed that the four umami peptides could be embedded into the binding pocket of the taste receptor T1R3 cavity. The major interactions forces were hydrogen bonding and hydrophobic interactions, and the key sites for T1R3 binding were Glu217, Glu148, and Glu45.

Identification, taste properties and molecular docking of novel umami peptides from Butyriboletus roseoflavus

Identification, taste properties and molecular docking of novel umami peptides from Butyriboletus roseoflavus

Virtual screening, molecular docking and identification of umami peptides derived from Oncorhynchus mykiss

Oncorhynchus mykiss is delicious and contains abundant flavor substances. However, few studies focused on umami peptides of O. mykiss. In the current work, umami peptides derived from O. mykiss were identified using virtual screening, molecular docking, and electronic tongue analysis. First, the O. mykiss protein was hydrolyzed using the PeptideCutter online enzymolysis program. Subsequently, water-soluble and toxicity screening were performed by Innovagen and ToxinPred software, respectively. The potential peptides were docked with umami receptor T1R1/T1R3. Furthermore, taste properties of potential peptides were validated by electronic tongue. Docking results suggested that the three tetrapeptide EANK, EEAK, and EMQK could enter the binding pocket in the T1R1 cavity, wherein Arg151, Asp147, Gln52, and Arg277 may play key roles in the production of umami taste. Electronic tongue results showed that the umami value of EANK, EEAK, and EMQK were stronger than monosodium glutamate. This work provides a new insight for the screening of umami peptides in O. mykiss.

A strategy for screening novel umami dipeptides based on common feature pharmacophore and molecular docking

To shorten the complex and tedious process of traditional umami peptide identification, a novel model based on common feature pharmacophore (HipHop, a ligand molecule-based screening method) and molecular docking (a receptor protein-based screening method) was established for umami peptide screening. In this study, HipHop was used to perform a preliminary screening of peptides. Dipeptides with potential umami activity were docked into the umami taste receptor T1R1/T1R3 for a second screening. Twenty previously unreported umami dipeptides identified through virtual screening were validated using sensory evaluation and electronic tongue analysis. All 20 dipeptides (HE, HD, KE, EH, ET, EQ, DH, DR, DQ, DN, DY, DM, DI, DV, QE, QD, NE, ND, CE, and SE) had umami taste with umami threshold values ranging from 0.094 to 1.517 mmol/L. Therefore, when we increased the screening criteria for docking energy to −60 kcal/mol, the virtual screening results had 100% accuracy. The T1R1-peptide complexes of the four dipeptides with the lowest umami threshold values were subjected to molecular dynamics (MD) simulations for 100 ns, and the results showed that the four umami dipeptides remained in the starting active cavity. Overall, this screening strategy could be applied to the rapid screening of umami peptides in food products.

Identification of novel umami peptides from Boletus edulis and its mechanism via sensory analysis and molecular simulation approaches

The study aimed to identify umami peptides from Boletus edulis and explore their umami mechanism. 421, 713 and 616 peptides identified by LC-MS/MS from control sample (CS), enzymatically extracted sample (EES) and high-pressure cooking sample (HPCS), respectively. According to molecular docking study, three potential umami peptides (DGF, KCGQ and HHYE) were chemically synthesized for sensory evaluation. DGF/HHYE had the lowest umami recognition threshold values in the absence (0.37 mmol/L for DGF)/presence (0.21 mmol/L for HHYE) of monosodium l-glutamate. KCGQ exhibited the strongest synergistic umami effect. Molecular dynamic simulation revealed that hydrogen bonds and hydrophobic interactions were the major intermolecular interaction forces and the charged amino acid residues (D1, E4 and K1) in umami peptides were dominate in the molecular recognition of umami peptides and the receptor. This study lays the groundwork for the efficient screening of umami peptides from edible fungi and contributes to the umami peptides structure–activity relationship research.

Taste peptides derived from Stropharia rugosoannulata fermentation mycelium and molecular docking to the taste receptor T1R1/T1R3.

This study identified the peptides in the fermentation mycelia of Stropharia rugosoannulata. The molecular weight of the peptides was below 3,000 Da. Heptapeptides to decapeptides were the main peptides in the fermentation mycelia of S. rugosoannulata. More than 50% of the peptides had salty and umami taste characteristics, and the long-chain peptides (decapeptides to 24 peptides) also played an essential role in the pleasant taste characteristics of mycelium. In the salty and umami peptide of S. rugosoannulata, the distribution of non-polar hydrophobic amino acids and polar-uncharged amino acids accounted for a relatively high proportion, and the proportion of polar-uncharged amino acids further increased, with the extension of the peptide chain. P, F, I, l, V, G, S, T, and D were the amino acids with a high proportion in the peptides. The taste peptides can bind to more than 60% of the active amino acid residues in the cavity-binding domain of the T1R1/T1R3 receptors. Hydrogen bond interaction was the primary mode of interaction between the peptides and the receptor. The first and second amino acid residues (such as S, V, E, K, G, and A) at the C-terminal and N-terminal of the peptides were easy to bind to T1R1/T1R3 receptors. Asp108, Asn150, Asp147, Glu301, Asp219, Asp243, Glu70, Asp218 in T1R1, and Glu45, Glu148, Glu301, Glu48, and Ala46 in TIR3 were the key active amino acid sites of taste peptides binding to T1R1/T1R3 receptors.

A novel intuitionistic fuzzy rough set model and its application to enhance umami peptide prediction

Datasets mainly consist of ambiguous objects, redundant and uncertain attribute values which increase complexity, time and cost in Knowledge Discovery in Databases (KDD) process. Rough set-based attribute reduction techniques deals with ambiguity but fails to handle uncertainty available in a real-valued dataset. Combining rough set with intuitionistic fuzzy set provides a great opportunity to the researchers working on attribute reduction of real-valued datasets as it provides better results when compared to the traditional fuzzy rough set theory. In this paper, we present a new intuitionistic fuzzy rough set model for attribute reduction to avoid misclassification and perturbation by handling hesitancy, ambiguity and uncertainty present in a dataset. We define an intuitionistic fuzzy tolerance relation between two objects along with lower and upper approximations based on that relation. Next, the concept of Degree of dependency is utilized to present attribute reduction by using model due to its better performing nature over other methods. The algorithm of the proposed technique is applied on benchmark datasets to perform a comparative study with recent approaches. We obtain the best result for the reduced Breast Cancer dataset by our proposed approach, with an accuracy of 98.96% along with 0.90 standard deviation by using SMO classifier. Finally, our proposed method is used to present a methodology to improve the prediction of umami peptides. Here, we record the best results with sensitivity, specificity, accuracy, AUC, and MCC of 96.8%, 93.6%, 97.7%, 0.988, and 0.899, respectively. From the experiments, it can be concluded that our method outperforms the existing methods.

Umami polypeptide detection system targeting the human T1R1 receptor and its taste-presenting mechanism

Umami is one of five basic tastes, the elucidation of its mechanism by the study of the interaction between umami polypeptides and hT1R1 umami receptors is of great significance. However, research on umami peptides targeting human T1R1 receptors is lacking, and the molecular mechanism remains elusive. Here, we successfully established a system to detect umami peptides targeting human T1R1 receptors by fluorescence spectroscopy, Surface Plasmon Resonance (SPR) and computational simulation. The sensory evaluation, calculated Kd value, and experimental affinity results between the four selected umami peptides (GRVSNCAA, KGDEESLA, KGGGGP, and TGDPEK) and glutamate were tested using this system, and all matched well. The maximum Ka value of GRVSNCAA was 479.55 M-1, and the minimum affinity of TGDPEK was 2.67 M-1. Computational simulations showed that the different peptide binding sites in the hT1R1 binding pocket occupied due to conformational changes are important factors for different taste thresholds, and that peptide hydrophobicity plays an important role in regulating affinity. Thus, our study enables rapid screening of high-intensity umami peptides and the development of T1R1 receptor-based umami detection sensors.

Umami peptides screened based on peptidomics and virtual screening from Ruditapes philippinarum and Mactra veneriformis clams

The existing technology used for screening umami peptides is time-consuming and labor-intensive, making it difficult to meet the requirements of rapid screening of peptides. In this study, a high-throughput screening method for umami peptides was established based on peptidomics and virtual screening including the mass spectrometry, iUmami-SCM, PeptideRanker, and T1R1/T1R3 receptor. Subsequently, they were characterized and validated using sensory evaluation and electronic tongue. Results showed that 18 potential umami peptides were screened from two clams. Among them, 16 peptides had umami characteristics with thresholds range 0.123–1.481 mmol/L, and the accuracy of the screening method was about 88.9%. Additionally, active sites such as Tyr143, Gly144, Ser146, Ala145, His121, Ser123, and Glu277 may play a critical role in flavor presentation by molecular docking with T1R1/T1R3. The paper could provide a fast and reliable method for screening umami peptides as well as lay the foundation for novel strategies for evaluating umami taste.

Umami and umami‐enhancing peptides from myofibrillar protein hydrolysates in low‐sodium dry‐cured Spanish mackerel (Scomberomorus niphonius) under the action of Lactobacillus plantarum

SummaryLactobacillus plantarum was involved in producing low‐salt (2%, w/w) dry‐cured Spanish mackerel, and its effect on the degradation of myofibrillar protein and production of umami peptides was investigated. Results showed that the dominant microbiome of the sample was Lactobacillus plantarum, accounting for 95.7% of the microbial community. The umami peptides in this dry‐cured mackerel were extracted and separated by ultra‐filtration and gel filtration chromatography and further identified by Nano‐LC–MS/MS. Five umami‐enhancing peptides, including TFYNELRV (1040 Da), TFYNELR (941 Da), TLFQPSF (838 Da), LYANNVL (805 Da) and FAGDDAPRAVFPS (1348 Da), were identified to be derived from myofibrillar protein, and the percentage of their hydrophobic amino acid were 42.85%, 33.33%, 57.14%, 57.14% and 53.84%, respectively. The synthetic peptides of these five umami peptides showed an umami‐enhancing threshold value ranging from 0.34 to 0.45 mg mL−1 through sensory evaluation. The SDS‐PAGE analysis exhibited that actin band intensity was decreased during the processing of dry‐cured mackerel. Therefore, Lactobacillus plantarum has the potential to improve the hydrolysis of myofibrillar protein to produce umami peptides in dry‐cured mackerel.

Characterization of Peanut Protein Hydrolysate and Structural Identification of Umami-Enhancing Peptides.

Umami peptides are naturally found in various foods and have been proven to be essential components contributing to food taste. Defatted peanut powder hydrolysate produced by a multiprotease (Flavorzyme, Alcalase, and Protamex) was found to elicit an umami taste and umami-enhancing effect. The taste profiles, hydrolysis efficiency, amino acids, molecular weight distribution, Fourier transform infrared spectroscopy (FT-IR), and separation fractions obtained by ultrafiltration were evaluated. The results showed that peanut protein was extensively hydrolyzed to give mainly (up to 96.84%) free amino acids and peptides with low molecular weights (<1000 Da). Furthermore, β-sheets were the major secondary structure. Fractions of 1–3000 Da and <1000 Da prominently contributed to the umami taste and umami enhancement. To obtain umami-enhancing peptides, these two fractions were further purified by gel filtration chromatography, followed by sensory evaluation. These peptides were identified as ADSYRLP, DPLKY, EAFRVL, EFHNR, and SDLYVR by ultra-performance liquid chromatography (UPLC), and had estimated thresholds of 0.107, 0.164, 0.134, 0.148, and 0.132 mmol/L, respectively. According to the results of this work, defatted peanut powder hydrolysate had an umami taste and umami-enhancing effect, and is a potential excellent umami peptide precursor material for the food industry.

Taste mechanism of umami peptides from Chinese traditional fermented fish (Chouguiyu) based on molecular docking using umami receptor T1R1/T1R3

Umami peptides formed during fermentation of Chouguiyu contribute to its unique taste. In this study, the umami taste of peptide extract from Chouguiyu was improved after fermentation, as determined by sensory evaluation. After umami peptide identification using peptidomics, molecular docking with T1R1/T1R3 was used to evaluate the likely taste mechanism. There were 400 umami peptides identified in Chouguiyu, most of which were significantly enhanced after fermentation. These peptides were hydrolyzed from 77 precursor proteins, mainly including myosin, troponin, and titin, at multiple locations. The umami structures in the six core umami peptides with the lowest binding energy were easy to connect with Ser, Glu, His, Gln, Arg and Lys residues in T1R3 through hydrogen bond and salt bridge. The hydrogen bond, hydrophilcity, aromatic interaction, and solvent accessible surface were the main interaction surface forces. This study provides important information of the unique taste formation in Chouguiyu based on umami peptides.

Novel insight into the formation mechanism of umami peptides based on microbial metabolism in Chouguiyu, a traditional Chinese fermented fish

Umami peptides formed by microbial metabolism play an important role in the umami taste of Chouguiyu. In this study, 138 umami peptides and 6 kinds of proteases in two categories from 35 microbial genera were identified from Chouguiyu during the fermentation process by peptidomics and metagenomics analysis, respectively. The interaction network maps between the umami peptides and protease-producing microbial genera in each protease classification were constructed based on Pearson’s correlation coefficient after a two-way orthogonal partial least squares (O2PLS) evaluation. The proteases classified in 34 clusters of orthologous groups (COG) from Vagococcus, Peptostreptococcus, Acinetobacter, Psychrobacter, and Enterococcus played a major role in the formation of umami peptides. The core umami peptides with the highest abundance and correlation were mainly derived from troponin and myosin in mandarin fish. The lactic acid bacteria contributed most to the hydrolysis preparation of these umami peptides. This study is beneficial to screen the proteases and related microbial strains to improve the umami taste of Chouguiyu.

Characteristics of umami peptides identified from porcine bone soup and molecular docking to the taste receptor T1R1/T1R3

To study the umami peptides derived from porcine bone soup, ultrafiltration fractions with molecular weight less than 1 kDa were screened by sensory analysis which showed higher umami intensity. Four potential umami peptides were identified from the screened fractions by Nano-LC-Q-TOF-MS/MS, among which FSGLDGAK, FAGDDAPR and FSGLDGSK were proved to have dominant umami taste by sensory evaluation and electronic tongue. The threshold of the three peptides ranged from 0.1 mM to 0.89 mM. In addition, FSGLDGSK had the highest umami intensity and exhibited a significant umami-enhancing effect in a 0.35% monosodium glutamate solution. The results of molecular docking simulation showed that the key binding sites of taste receptor type 1 member 1 (His71, Asp108 and Glu301) and taste receptor type 1 member 3 (Glu48, Ser104 and His145) were crucial to the interaction with the umami peptides. Besides, electrostatic interaction and hydrogen bond mainly contributed to the mechanism of umami taste.

Characterization of novel umami-active peptides from Stropharia rugoso-annulata mushroom and in silico study on action mechanism

Umami peptides can supplement and enhance the overall taste of food, making it more harmonious, soft, and full-bodied. Stropharia rugoso-annulata mushroom is famous for its umami and pleasant flavor, however, there were no report on its umami peptides. In this study, umami peptides from S. rugoso-annulata were isolated and characterized, as well as to analyze the action mechanism in silico molecular docking approach. By ultrafiltration, gel filtration chromatography, HPLC, and UHPLC-Q-Orbitrap-MS2, five peptides, EPLCNQ, SGCVNEL, PHEMQ, SEPSHF, and ESCAPQL were identified. According to the sensory evaluation and electronic tongue analysis, they had good umami activity and their umami threshold values were in the range of 0.167–0.390 mmol/L. EPLCNQ and SGCVNEL had higher umami intensity than others. Molecular docking of the identified peptides with the umami taste receptor T1R1/T1R3 indicated that the peptides can enter the binding pocket in the Venus flytrap domain of T1R3 cavity, wherein Glu45, Ser104, and His145 may play major roles in the binding interactions of peptides and receptor, forming more stable hydrogen bonds to producing strong umami taste. The study expands the source range of umami peptides and potential raw material of value-added umami-flavorings, and provides further insight into understanding the flavor mechanisms of mushrooms.

Research progress in the screening and evaluation of umami peptides.

Umami is an important element affecting food taste, and the development of umami peptides is a topic of interest in food-flavoring research. The existing technology used for traditional screening of umami peptides is time-consuming and labor-intensive, making it difficult to meet the requirements of high-throughput screening, which limits the rapid development of umami peptides. The difficulty in performing a standard measurement of umami intensity is another problem that restricts the development of umami peptides. The existing methods are not sensitive and specific, making it difficult to achieve a standard evaluation of umami taste. This review summarizes the umami receptors and umami peptides, focusing on the problems restricting the development of umami peptides, high-throughput screening, and establishment of evaluation standards. The rapid screening of umami peptides was realized based on molecular docking technology and a machine learning method, and the standard evaluation of umami could be realized with a bionic taste sensor. The progress of rapid screening and evaluation methods significantly promotes the study of umami peptides and increases its application in the seasoning industry.

Identification and comparison of umami-peptides in commercially available dry-cured Spanish mackerels (Scomberomorus niphonius)

Dry-cured Spanish mackerel (DSM; Scomberomorus niphonius) is a popularity worldwide dry-cured marine fish product due to its salty and umami flavor. Umami peptides from eight commercial DSMs were identified and compared, and their molecular mechanisms were evaluated via molecular simulation. The results showed that the sequence of peptides varied in different DSMs, wherein only ten sequences were repeated across multiple samples and the remaining 19 were detected in only one sample. The sensory characteristics of eight repeated peptides were evaluated, and four were found to exhibit umami taste and umami-enhancing effects, including Arg-Asp, Asp-Gly-Val, Asp-Arg, and Asp-Lys. They all had a strong affinity for umami receptors, and several amino acid residues of the receptors were mobilized as binding sites to form hydrogen bonds and hydrophobic bonds in ligand-receptor interactions. These results indicated that DSM was rich in umami and umami-enhancing peptides, but their sequence were different in different DSMs.

Isolation and screening of umami peptides from preserved egg yolk by nano-HPLC-MS/MS and molecular docking

The material basis leading to the rich umami flavor of preserved egg yolk is poorly understood. This study used nano-high-performance liquid chromatography − tandem mass spectrometry (nano-HPLC-MS/MS) to isolate, identify, and screen umami peptides from preserved egg yolk. Five novel umami peptides—AGFMPLP, APYSGY, PPMF, SLSSLMK, and VAMNPVDHPH—were identified. Molecular docking showed that Phe527 on the taste receptor T1R1/T1R3 (T1R1, taste receptor type 1 member 1; T1R3, taste receptor type 1 member 3) was the key interaction site. Hydrogen bonding, electrostatic interactions, and hydrophobic interactions were the main binding forces between T1R1/T1R3 and umami peptides. These results contribute to understanding the umami peptides in preserved egg yolk and the interaction mechanism between umami peptides and umami receptors.

Study on the Relationship between Structure and Taste Activity of the Umami Peptide of Stropharia Rugosoannulata Prepared by Ultrasound

Study on the Relationship between Structure and Taste Activity of the Umami Peptide of Stropharia Rugosoannulata Prepared by Ultrasound

In-silico investigation of umami peptides with receptor T1R1/T1R3 for the discovering potential targets: A combined modeling approach

Umami, providing amino acids/peptides for animal growth, represents one of the major attractive taste modalities. The biochemical and umami properties of peptide are both important for scientific research and food industry. In this study, we did the sequence analysis of 205 umami peptides with 2-18 amino acids, sought the active sites of umami peptides by quantum chemical simulations and investigated their recognition residues with receptor T1R1/T1R3 by molecular docking. The results showed the peptides with 2-3 amino acids accounting for 44% of the total umami peptides. Residues D and E are the key active sites no matter where they are in the peptides (N-terminal, C-terminal or middle), when umami peptides contain D/E residues. N69, D147, R151, A170, S172, S276 and R277 residues in T1R1 receptor were deemed to be the key residues binding umami peptides. Finally, a powerful decision rule for umami peptides was proposed to predict potential umami peptides, which was convenient and efficient.