Umami Intensity Research Articles

Non-destructive assessment of equivalent umami concentrations in salmon using hyperspectral imaging technology combined with multivariate algorithms

This study utilized equivalent umami concentrations (EUC) to characterize umami intensity in salmon with different freeze–thaw times. A rapid and non-destructive method was established to determine EUC values in salmon which is based on hyperspectral imaging (HSI) system combined with multiple characteristic variable screening methods. The established CARS-PLS model showed greater advantages in correlating the reference values of spectral data with EUC in salmon with Rc of 0.9012, Rp of 0.9009, RMSECV of 0.82, and RMSEP of 0.88. The model was employed pixel-wise to visualize the distribution of EUC with different freeze–thaw times, which demonstrated the reduction of EUC value with the increasing of freeze–thaw times. Therefore, this reseearch showed hyperspectral imaging (HSI) system combined with chemometrics possesses a substantial capability to predict and visualize the EUC of salmon, which would provide an intuitive understanding of salmon quality prediction and detection.

Protein Hydrolysates from Pleurotus geesteranus Modified by Bacillus amyloliquefaciens γ-Glutamyl Transpeptidase Exhibit a Remarkable Taste-Enhancing Effect

Long-term high salt intake exerts a negative impact on human health. The excessive use of sodium substitutes in the food industry can lead to decreased sensory quality of food. γ-Glutamyl peptides with pronounced taste-enhancing effects can offer an alternative approach to salt reduction. However, the content and yield of γ-glutamyl peptides in natural foods are relatively low. Enzyme-catalyzed synthesis of γ-glutamyl peptides provides a feasible solution. In this study, Pleurotus geesteranus was hydrolyzed by Flavourzyme to generate protein hydrolysates. Subsequently, they were modified by Bacillus amyloliquefaciens γ-glutamyl transpeptidase to generate γ-glutamyl peptides. The reaction conditions were optimized and their taste-enhancing effects were evaluated. Their peptide sequences were identified by parallel reaction monitoring with liquid chromatography-tandem mass spectrometry and analyzed using molecular docking. The optimal conditions for generation of γ-glutamyl peptides were a pH of 10.0, an enzyme condition of 1.2 U/g, and a reaction time of 2 h, which can elicit a strong kokumi taste. Notably, it exhibited a remarkable taste-enhancing effect for umami intensity (76.07%) and saltiness intensity (1.23-fold). Several novel γ-glutamyl peptide sequences were found by liquid chromatography-tandem mass spectrometry, whereas the binding to the calcium-sensing receptor was confirmed by molecular docking analysis. Overall, γ-glutamyl peptides from P. geesteranus could significantly enhance the umami and salt tastes, which can serve as promising taste enhancers.

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.

Application of efficient pre‐treatment by physical fields for improving the taste and flavor of processed chicken enzymatic hydrolysate

In the condiment industry, people usually use enzymatic hydrolyzate to improve the umami of the product, and there are few reports on the umami intensity of the enzymatic hydrolysate. To explore the differences in taste and flavor of the samples pretreated with different physical fields, the chicken was pretreated by ultrasound (US, 600 W, 30 min), infrared radiation (IR, 90°C, 30 min), and radio frequency (RF, 120 mm, 30 min), respectively, and followed by a two-step enzymatic hydrolysis. Results revealed that the chicken enzymatic hydrolyzate after RF pretreatment (120 mm, 30 min) had the best overall taste and stronger umami. The sample treated with 90°C IR has a richer flavor, while there were no significant changes in taste of the 600 W ultrasound treatment group compared with the “control.” Therefore, RF pretreatment (120 mm, 30 min) is more suitable for industrial to produce low cost and high umami chicken enzymatic hydrolyzates. Practical applications In the condiment food industry, people usually use umami-rich enzymatic hydrolysates to improve the umami taste of products. The 120 mm plate spacing radio frequency pretreatment proposed in this study for 30 min before enzymolysis can significantly improve the taste characteristics of the chicken enzymolysate, significantly enhance its saltness and umami, and make the overall taste more harmonious. It provides a certain theoretical basis for the industrial production of low-cost umami-enhancing enzymatic hydrolysis products.

Umami compounds present in umami fraction of acid-hydrolyzed Spirulina (Spirulina platensis)

Spirulina (Spirulina platensis) has been used in food as a protein-rich source. Its umami taste led to the application in meat products, pasta, biscuits and extrusion products. Spirulina hydrolysate has a more intense umami taste. Umami compounds in acid-hydrolysate of the spirulina were investigated in this present study. The spirulina hydrolysate was proven to have a higher umami intensity compared to unhydrolyzed one. Its ultrafiltration fraction with molecular weights <3000 Da was further separated by Sephadex G-25 chromatography, to obtain an umami fraction. The umami fraction was containing succinic acid and free L-glutamic acid at concentrations much higher than their umami taste thresholds. Di- and tripeptides identified as glutamyl peptides were also found abundantly in the fraction.

Insight into the characteristics of cider fermented by single and co-culture with Saccharomyces cerevisiae and Schizosaccharomyces pombe based on metabolomic and transcriptomic approaches

This study aimed to explore the effect of single and co-culture with Saccharomyces cerevisiae and Schizosaccharomyces pombe on the quality of cider. It was found that the interaction effect was observed in co-culture fermentation (CF) of cider with S. cerevisiae CICC 31084 and S. pombe CICC 1760. Meanwhile, aroma and taste quality of CF was significantly improved involving increase of fruity and floral aroma, which might result from the balance of esters, higher alcohols and terpenes. Moreover, the umami intensity of CF was enhanced, and the taste of sourness and astringency became weaker, which could be due to the higher content of umami amino acid and deacidification of malate. Additionally, a combined metabolic and RNA sequencing analyses revealed a clearer association between flavor quality of cider and gene expression of yeasts. Bioinformatic analysis revealed that the varying genes and metabolites were mainly involved in pathways of carbohydrate, amino acids, energy and terpenes backbone metabolism. Finally, a metabolic pathway visualized the changes of significantly changed metabolites and differentially expressed genes in single and co-culture ciders. This study provided new insights into cider production and facilitated the application of co-culture fermentation technology in fruits cidermaking.

Evaluation of beef steak flavor development in vacuum rollstock packaging under two lighting sources

The objective of this study was to determine the influence of lighting type and display duration on flavor development in multiple beef muscles. Paired beef top sirloin butts, strip loins, and tenderloins were collected from USDA Low Choice carcasses (Small00 to Small100 marbling score, n = 16). Subprimals were wet-aged in the absence of light for 7 d post-mortem at 0 to 4⁰C before being fabricated into 2.54 cm steaks representing the Gluteus medius (GM), Longissimus lumborum (LL), and Psoas major (PM). Steaks were packaged individually in vacuum rollstock packaging (VRP), and assigned to either light-emitting diode (LED) or fluorescent (FLUR) display cases for a display period of 0, 2, 6, or 10 d. All steaks were assigned to either trained descriptive panel analysis (n = 384) or volatile compound analysis (n = 384) and cooked to a medium degree of doneness (71⁰C). Trained descriptive panelists evaluated samples for beef flavor identity, brown/roasted, bloody/serumy, fat-like, liver-like, oxidized, umami, sweet, salty, bitter, sour, overall tenderness, and overall juiciness attributes. Two-way interactions occurred between lighting type and display duration, showing increased tenderness sooner during display for LED steaks, and lower umami intensity in FLUR steaks after 10 d (P &amp;lt; 0.001). Lighting and muscle type showed more tender LL and PM steaks in LED lighting (P ≤ 0.001). Lighting and display duration interactions also showed increased concentrations of 2,3- Butanedione under FLUR light and ethyl benzene under LED display (P ≤ &amp;nbsp;0.043), while lighting and muscle type showed greater concentrations of alcohols and carboxylic acids in LL steaks under LED lighting (P ≤ 0.046). Discriminate function analyses were also used to evaluate relationships between trained sensory attributes and volatile flavor compounds. Nonetheless, lighting type showed no clear impact on beef flavor and volatile compounds of individually packaged beef steaks.

The enhancement of the perception of saltiness by umami sensation elicited by flavor enhancers in salt solutions

Health concerns related to the intake of salt have encouraged the investigation into sodium reduction by examining the taste-taste interaction between the perception of saltiness and umami. The effect of saltiness enhancement and sodium reduction of four kinds of umami carrier (WSA, MSG, IMP, and I + G) in a salt model solution with different salt concentrations (2.03–13.94 g/L) were investigated using the two-alternative forced-choice (2-AFC) and generalized Labeled Magnitude Scale (gLMS). The saltiness difference thresholds (DT) under different umami carrier were further explored using the constant stimuli method. The results showed that umami carriers had effective effects of saliness enhancement in the salt solutions with different concentrations, and higher enhancemen levels were obtained at larger salt concentrations. The level of saltiness enhancement were varied between the different umami intensity and carriers, and WSA carrier with moderate intensity had the maximum sodium reduction percentages which reached to 24.25%. Besides, the DT values of saltiness taste were increased under umami carrier, which means that more salt can be reduced without evoking a variation in saltiness. The present work not only provided insight into the effect of umami chemicals on the saltiness perception and saltiness DT values but also presented valuable information regarding flavor when developing low sodium foods and contributing to the development of more healthful products that meet current nutritional recommendations.

Insights into ultrasonic treatment on the mechanism of proteolysis and taste improvement of defective dry-cured ham

To investigate the effects of ultrasonic treatment on proteolysis and taste development of defective dry-cured ham, sensory attributes, enzyme activities, protein degradation and free amino acids were evaluated after different ultrasonic treatments. The ultrasonic treatment of 1000 W & 50 °C significantly increased the intensities of overall taste, umami, sweetness and richness, and decreased bitterness values compared with other groups. The residual activities of DPP I and cathepsin B + L in 1000 W & 50 °C maintained 48.71% and 24.94% of control group, respectively; the intense degradation of structural proteins was observed by label-free proteomics, accordingly. The contents of total free amino acids from 4522.64 mg/100 g muscles in control group increased to 5838.75 mg/100 g muscles in 1000 W & 50 °C; the largest increase of sweet and umami amino acids observed in 1000 W & 50 °C was responsible for the improvement of taste quality of defective dry-cured ham.

Preparation and Taste Characteristics of Kokumi N-Lactoyl Phenylalanine in the Presence of Phenylalanine and Lactate.

N-l-Lactoyl phenylalanine (N-l-lactoyl-Phe) has been identified as a taste-active contributor in many fermented foods. However, its preparation, taste property, and content in foodstuffs are little known to date. In the current study, two preparation technologies of N-l-lactoyl-Phe including heating and enzymatic methods were investigated. Other investigations include its taste property and quantification in several fermented foods. The results indicated that the heating preparation and enzymatic preparation only produced N-l-lactoyl-Phe instead of N-d-lactoyl-Phe in the presence of l-lactate/d-lactate and l-phenylalanine (Phe). A high yield (58.0% ± 0.7%) of N-l-lactoyl-Phe was achieved under the following conditions: Phe, lactate, CaO, and water at molar ratios of 1:8:0.3:9 kept at 100 °C for 3 h. With nine enzymes, a maximum yield of 21.2% ± 0.3% was achieved in the aqueous solution under mild operating conditions: 0.18 M Phe, 0.90 M lactate, 5 g/L Debitrase HYW 20, pH 8, and 55 °C for 24 h. The sensory evaluation revealed that N-l-lactoyl-Phe in water enhanced the salty and umami intensity. It also enhanced the thickness, mouthfulness, and continuity of salt solution, model broth, and chicken broth, revealing that N-l-lactoyl-Phe was a kokumi-active compound. The kokumi thresholds of N-l-lactoyl-Phe in these solutions were 50, 50, and 25 mg/L, respectively. N-l-Lactoyl-Phe was quantified in traditional Chinese fermented foods as 30.12 ± 0.28 mg/kg in preserved pickles, 14.11 ± 0.14 mg/kg in soybean paste, 4.87 ± 0.16 mg/kg in fermented bean, 0.71 ± 0.11 mg/kg in rice vinegar, and 20.34 ± 0.18 mg/kg in soy sauce. These results revealed the potential of N-l-lactoyl-Phe as a taste enhancer, presenting a new opportunity for the food industry.

Determination of umami compounds in edible fungi and evaluation of salty enhancement effect of Antler fungus enzymatic hydrolysate

The demand for low-salt foods is increasing due to their health benefits. Umami is known to enhance salty, and a large amount of umami components have been identified in edible fungi. 5′-nucleotides and umami amino acids from nine species of edible fungi were quantified. The equal umami concentration (EUC) in nine edible fungi was within the range of 37.7–1317.72 g MSG/100 g, and umami intensity as determined by electronic tongue and sensory evaluation was within the range of 11.22–13.53 and 2.85–5.55, respectively. Antler fungus had the highest umami intensity. Umami amino acids and nucleotides could increase salty intensity of NaCl at medium and high concentrations. The enzymatic hydrolysate of Antler fungus at higher concentrations could more effectively enhance salty taste of NaCl at lower concentration. This synergistic effect between umami and salty indicates that Antler fungus can potentially be used as an ingredient in low-salt foods.

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.

Optimization of extrusion cooking conditions for seasoning base production from sea mustard (Undaria pinnatifida)

Sea mustard (Undaria pinnatifida), an important edible seaweed belonging to the brown algal family of Alariaceae, contains copious physiologically active substances. It has long been popular in Korea as a food and is frequently consumed in the form of soup. It is also commercially available as a home meal replacement. In this study, we developed a seasoning key base with a high degree of sensory preference from sea mustard using the extrusion cooking process. Extrusion cooking conditions were optimized through response surface methodology. Barrel temperature (X1, 140°C–160°C) and screw speed (X2, 158–315 rpm) were set as independent variables, and overall preference was determined as the dependent variable (Y, points). An optimal condition was obtained at X1 = 148.5°C and X2 = 315 rpm, and the dependent variable (Y, overall acceptance) was 7.95 points, similar to the experimental value of 7.81. Umami taste had a relationship with the overall acceptance of sea mustard seasoning. In the electronic nose and tongue, increased sourness and umami intensities were associated with the highest sensory score. The samples were separated well by each characteristic via principal component analysis. Collectively, our study provides imperative preliminary data for the development of various seasonings using sea mustard.

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.

Biomimetic ion nanochannels for sensing umami substances

Umami is one of the basic taste sensing, and represents the recognition of N-containing compounds capable of evaluating the nutritious contents of food. Although several sensors have been developed, the assessment of umami intensity remains challenging due to the limitations of sensor specificity, sensitivity, and performance stability. Here we present a biomimetic conical nanochannels system integrated with Venus flytrap (VFT) domain from human umami receptor T1R1 subunit to meet the concern. By taking advantage of sensitive transmembrane ionic flux change, the functional nanochannels could precisely distinguish umami substances from other tastants. Detailed mechanism analysis reveals that specific binding between T1R1 and umami substances triggers local conformation change and surface charge redistribution of the protein, which modulates the ionic current. This study initiates the application of nanochannel device in taste perception, which could help to disclose umami perception mechanism and screen new umami substances.

Characterization and molecular docking study of taste peptides from chicken soup by sensory analysis combined with nano-LC-Q-TOF-MS/MS

Dynamic quantitative descriptive analysis and temporal dominance of sensations were used to analyze the data of sensory evaluation and characterize the taste profiles of chicken soup. The results showed that umami and saltiness were the dominant taste of the chicken soup and chicken soup with ginger. Nine taste peptides were identified by Nano-LC-Q-TOF-MS/MS and evaluated by sensory evaluation and electronic tongue. Among the identified peptides, AGPSIVH, IKDPHVD and TPPKID were characterized by umami. Besides, IKDPHVD, FAGDDAPR and NALNDITSL showed umami-enhancing effects. The results of molecular docking suggested that the key binding sites were crucial to the docking, such as His71, Ser107 and Glu301 of taste receptor type 1 member 1 and Asp216, Ser104, His145 and Ala302 of taste receptor type 1 member 3. Considering the ranking of sensory analysis, the interaction with taste receptor type 1 member 3 was more likely to relate to the umami intensity of peptides.

Effect of Yellowing Duration on the Chemical Profile of Yellow Tea and the Associations with Sensory Traits.

The yellowing process is the crucial step to form the characteristic sensory and chemical properties of yellow tea. To investigate the chemical changes and the associations with sensory traits during yellowing, yellow teas with different yellowing times (0–13 h) were prepared for sensory evaluation and chemical analysis. The intensities of umami and green-tea aroma were reduced whereas sweet taste, mellow taste and sweet aroma were increased under long-term yellowing treatment. A total of 230 chemical constituents were determined, among which 25 non-volatiles and 42 volatiles were the key chemical contributors to sensory traits based on orthogonal partial least squares discrimination analysis (OPLS-DA), multiple factor analysis (MFA) and multidimensional alignment (MDA) analysis. The decrease in catechins, flavonol glycosides and caffeine and the increase in certain amino acids contributed to the elevated sweet taste and mellow taste. The sweet, woody and herbal odorants and the fermented and fatty odorants were the key contributors to the characteristic sensory feature of yellow tea with sweet aroma and over-oxidation aroma, including 7 ketones, 5 alcohols, 1 aldehyde, 5 acids, 4 esters, 5 hydrocarbons, 1 phenolic compound and 1 sulfocompound. This study reveals the sensory trait-related chemical changes in the yellowing process of tea, which provides a theoretical basis for the optimization of the yellowing process and quality control of yellow tea.

Detection of Umami Substances and Umami Intensity Based on Near-Infrared Spectroscopy

Detection of Umami Substances and Umami Intensity Based on Near-Infrared Spectroscopy

Interactions of umami with the four other basic tastes in equi-intense aqueous solutions

Previous research has shown that the addition of equi-intense concentrations of taste compounds leads to mixture suppression, with sweetness being the least suppressed taste while being the strongest suppressor of the other taste stimuli. However, perceived intensity of umami (savoury taste) within complex mixtures is less defined. Since maintaining savoury taste of foods at reduced salt levels is a growing need, this study investigated the role of umami in complex taste systems. Initially the concentrations of single tastants were adjusted until a trained sensory panel rated them as equi-intense using general labelled magnitude scales (gLMS). In order to evaluate the impact of umami taste on other tastes, and vice versa, three sample sets were prepared as binary and quinary systems. The first two sets utilised monosodium glutamate (MSG) as the umami tastant; one set without balancing the sodium level in MSG and another set accounting for it by the addition of sodium at an equivalent molarity. The third set used monopotassium L-glutamate monohydrate (MPG) as the source of umami to overcome the confounding influence of sodium. All samples were rated by trained sensory panellists. The results of the three studies conclude that umami taste does not enhance or suppress the perception of any other taste in binary aqueous taste systems (p > 0.05); whereas sweet, salty, sour and bitter significantly suppress the perception of umami in both binary and quinary systems (p < 0.05). Where glutamate and sodium chloride were used together, both umami and salty taste were maintained.