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The excessive consumption of sodium-containing seasonings has led to an increased burden on individuals' cardiovascular system and adversely affected their health. Recently, an innovative salt-reducing strategy utilizing salty peptides has emerged with promising prospects. In this study, Porphyra haitanensis salty peptides (PHSPs) was obtained through hydrolysis and ultrafiltration. The salty taste of 30 mg/mL PHSPs was comparable to that of about 40 mM NaCl. The higher proportion of umami and sweet amino acids in PHSPs was found, which contributed to the salty and umami taste. Factors affecting the flavor of PHSPs were also investigated. CaCl 2 exhibited the excellent synergistic enhancement with PHSPs on the salty taste, while the bitter taste of CaCl 2 was masked in the presence of PHSPs, which was attributed to the chelation between calcium and peptides. Above all, it is expected that PHSPs can be further developed and support the emerging salt-reducing strategy in food engineering. • Salty peptides from Porphyra haitanensis was obtained using green hydrolysis. • The combination of PHSPs and CaCl 2 exhibited effective saltiness-enhancing effect. • The chelation was innovatively proposed as an important way to enhance the flavor. • PHSPs provides effective support for the development of Na+-less seasoning products. [ABSTRACT FROM AUTHOR]

Porphyra sensu lato, a highly valuable edible seaweed renowned for its distinctive umami taste, undergoes significant taste variations during the harvest cycle, affecting product quality and pricing. In this study, umami-related metabolites in Pyropia haitanensis were investigated at different harvesting times using GC–MS metabolomic, targeted LC-MS analysis, and an electronic tongue taste evaluation. High concentrations of compounds, including glutamic acid, aspartic acid, and inosine 5′-monophosphate, were identified as the main contributors to the overall umami profile. The concentrations of the compounds and umami-enhancing substances, such as sugars, were negatively correlated as the harvesting period extended. The early harvested P. haitanensis exhibited a superior umami taste, which gradually decreased with subsequent harvest time. Proline, a known cold-resistance metabolite, accumulated as the seawater temperature decreased and the harvest period progressed. These findings provide insights into the optimal cultivation and harvesting practices for maintaining umami quality in P. haitanensis products. • Porphyra sensu lato is highly valued for its umami taste, driving significant economic value. • Early harvests exhibited superior umami taste, which gradually decreased over successive harvest periods. • Glutamic acid, aspartic acid, and inosine 5′-monophosphate were the main umami taste contributors. • Key umami substances contribute to guide harvest strategies for high-quality nori. • Changes in umami metabolites were negatively correlated with the harvesting period. [ABSTRACT FROM AUTHOR]

In order to guide manufacturers or consumers to choose frozen chicken wings (CWS) reasonably for roasting, the changes of sensory quality and physicochemical properties of CWS with different freezing storage time (0-12 months) after roasting were studied. The results showed that juiciness, fat flavor, meat flavor, and saltiness were the most important dominant attributes of roasted CWS, and their dominance rate gradually decreased from the ninth month. Increased (P < 0.05) TBARS value and water loss result in poor juiciness. According to the results of GC-IMS, the decrease of the dominant rate of meaty may be related to the decrease of the contents of 2-ethyl-5-methylpyrazine, benzene and thiazole. In addition, the accumulation of 1-octen-3-ol, n-hexanol, and hexanal caused by long-term freezing (> 9 months) give chicken wings a fishy and metallic taste. Therefore, CWS that have been frozen for more than 9 months are not ideal ingredients for roasting., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Minerals are reported to dominate the electrical properties of honey and indicate its botanical and geographical origins. In this study, Electrochemical Impedance Spectroscopy (EIS) was used to assess the relation between mineral elements, electrical properties and botanical origin using three honey varieties - Citrus sp., Eucalyptus sp., and Erica sp. These varieties are identified through pollen analysis and market labelling. Flame atomic absorption and emission spectroscopies were used to quantify the concentrations of eight elements (potassium, sodium, calcium, magnesium, manganese, zinc, copper, and iron). Among all the mineral elements, potassium showed a consistent correlation with impedance. The potassium estimation in honey and standard solutions (calibration curve) had similar sensitivities of 153.43 nF/mM and 132.68 nF/mM, respectively. Additionally, the analysis revealed that potassium dominates the mineral composition, with the other species present in minimal quantities. The EIS technique showed high sensitivity to potassium and other ionisable species, making it possible to classify the botanical origin of these three honey types. The EIS technique proved to be both time and cost effective, yielding a classification rate higher than that achieved by analysing mineral composition. [Display omitted] • Potassium is the predominant element influencing the electrical properties of honey. • Electrochemical impedance measurements provide a quantitative assessment of potassium concentration in honey. • An impedance-based sensor classifies honey samples according to their botanical origin. • The impedance-based sensor is time and cost-effective, when compared with mineral composition analysis. [ABSTRACT FROM AUTHOR]

• Acidification can occur during storage of Congou black tea. • Aroma enhancement process (AEP) accelerates acidification of black tea during storage. • AEP promotes conversion of Phenylalanine and glucose to oxalic acid, quinic acid, etc. • AEP also changes tea soup composition and increases acidification during storage. Acidification of aroma-enhanced black tea during storage was studied. UPLC-Q-TOF/MS (Ultra Performance Liquid Chromatography and Quadrupole-Time of Flight Mass Spectrometer) and HPLC (High-Performance Liquid Chromatography) analysis of non-volatile substances and organic acids revealed a decrease of soluble sugars and amino acids in aroma-enhanced black tea, while an increase in organic acids such as oxalic acid, malic acid and quinic acid. Further in vitro experiments indicated that the acidification of aroma-enhanced tea during storage can be attributed to decomposition of sugars and amino acids by heating, oxidation of aromatic aldehydes. Meanwhile, the amino acids, catechins, soluble sugars and flavonoids that constitute the taste of black tea are further reduced, changing the taste composition of tea infusion and further increasing its acidity. This study revealed the reasons for black tea acidification during aroma enhancement and storage and provided a theoretical basis for improving black tea quality. [ABSTRACT FROM AUTHOR]

• The contents of each component of quinoa extract were determined. • The structure of chenopodium saponins was analyzed. • The evaluation between electronic tongue and sensory evaluation was compared. • The source of quinoa's bitter taste was studied. While it is widely reported that saponins are the main source of the bitter taste in quinoa, this work found that some saponin compounds in quinoa husks elicit an umami response. The saponins were analyzed qualitatively and quantified by mass spectrometry (UPLC-MS). Two quinoa saponin compounds RT 46 (3-O-β- d -glucopyranosyl-(1 → 3)-α- l - arabino -pyranosyl-phytolaccagenic acid 28-O-β- d - gluco -pyranosyl), and RT 53 (3-O-β- d -glucopyranosyl-(1 → 4)-β- d -glucopyranosyl-28-O-hederagenin) were isolated from quinoa husks through separation and purification. According to eletronic tongue, the main taste response for those compounds was umami. It was found that the two quinoa saponins could bind to sweet and umami receptors. Besides saponins, various flavonoids and polyphenols also appeared in the UPLC-MS spectrum of crude saponins. The electronic tongue and sensory evaluation revealed that flavonoids and polyphenols showed obvious bitterness and astringency at very low concentrations. The study inferred that flavonoids and polyphenols are the main compounds that generate quinoa's bitter taste. [ABSTRACT FROM AUTHOR]

[Display omitted] • Over-fired drying can significantly improve the quality of LAGP tea. • LC–MS, HPLC and GC–MS revealed the taste and aroma compounds due to TSD and PLD. • A total of 5 compounds related to taste were selected by DOT > 1. • Concentrations of volatiles were 45.46% higher after PLD treatment. Lu'an Guapian (LAGP) tea, a representative Chinese roasted green tea, undergoes significant changes in taste and aroma during over-fired drying. However, limited studies have been conducted on these effects. This study employed metabolomics and sensory histology techniques to analyze non-volatile and volatile compounds the second drying and pulley liquefied gas drying (PLD) samples. The results revealed that after PLD, the samples exhibited lower umami, bitterness, and astringency; whereas floral, sweet, roasted, cooked corn-like, and cooked chestnut-like aromas became stronger. Among them, the content of (−)-epigallocatechin gallate, glutamic acid, and theogallin, which were closely related to taste, decreased by 4.5 %, 12.3 %, and 10.4 %, respectively. Eight key aroma components were identified as the main contributors to the sample aroma changes: (E)- β -ionone, dimethyl sulfide, (E,E)-2,4-heptadienal, geraniol, linalool, benzeneacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, and hexanal. This study provides a theoretical basis for enhancing the quality of LAGP teas. [ABSTRACT FROM AUTHOR]

• The quality and flavor of Noni during ripening were analyzed by different methods. • The optimum stage of nutrient accumulation was 7M−8M. • The volatile odor changed markedly from 8M to 9M. • The sour, astringent and fresh tastes contributed to the dominant taste. • The shared and unique compounds can be used as references for ripeness markers. Different ripeness plays a key role in the final quality and flavor of Noni products, but the variations of quality and flavor during Noni ripening are still unclear. In this study, physicochemical analysis combined with electronic nose, electronic tongue and gas chromatography-mass spectrometry (GC–MS) were used to investigate the effect of different ripeness levels on Noni fruit quality and flavor chemistry. The results showed that the optimum stage of nutrient accumulation is 7–8 ripe (7M−8M), in which especially the higher contents were 144Mg/100 g vitamin C, 11.08 g/kg polyphenols, 15.32 g/kg flavonoids and 2420Mg/kg potassium. Octanoic acid and hexanoic acid with an unfriendly odor began to decrease significantly after 8 ripe (8M), the lowest contents were 256.76 and 231.26 ng/g at 9 ripe (9M). Sour, astringent and fresh tastes are the dominant tastes of Noni fruit. Therefore, the optimum harvesting time of Noni fruit is 8M. [ABSTRACT FROM AUTHOR]

[Display omitted] • A method for identifying umami peptides was established with computer assistance. • Four novel umami peptides were discovered and validated. • Mechanism of umami peptide binding to T1R1/T1R3 was analyzed by computer simulation. • Amino acid types and residues in T1R1 that bind umami peptides were discovered. Umami peptides are an important component of food flavoring agents and have high nutritional value. This work aimed to identify umami peptides from tuna skeletal myosin using a new model method of computer simulation, explore their umami mechanism, and further validate the umami tastes with sensory evaluation. Umami peptides LADW, MEIDD, VAEQE, and EEAEGT were discovered, and all of them bound to taste type 1 receptor 1 and receptor 3 via hydrogen bonds and van der Waals forces to form stable complexes. LADW exhibited the best affinity energy and binding capability. Sensory evaluation and electronic tongue confirmed that all peptides possessed an umami taste, and LADW exhibited the strongest umami intensity. This study not only explored four novel umami peptides to improve the value of tuna skeletal myosin but also provided a new method for the rapid discovery of umami peptides. [ABSTRACT FROM AUTHOR]

• E-tongue discern Z. rouxii -contaminated apple juice at early stage. • E-tongue was more sensitive than test panel evaluation in detection of the spoilage. • PLSR enabled correlations between e-tongue data and contamination levels. Apple juice spoilage by Zygosaccharomyces rouxii could scarcely be identified at early stage. It is crucial to recognize the spoilage at early stage to prevent waste of products. In present study, electronic tongue was applied to detect the spoilage of Z. rouxii in apple juice, using taste evaluation by panelists as reference. Combined with linear discriminant analysis, identification of the contaminated juice was fulfilled after 12 h, equivalent to yeast population of less than 2.0 lg colony forming units/mL. At the level, panelists were not capable of discerning the spoilage. Sensors HA, ZZ, BB and BA were relatively more sensitive to the changes in overall taste of apple juice. Moreover, cell number of Z. rouxii could be properly quantified by partial least squares regression models with high determination coefficient of 0.98–0.99. Electronic tongue appears to be a powerful approach to realize early detection of contamination of Z. rouxii. [ABSTRACT FROM AUTHOR]

Highlights • A bioET combining biosensors sensitive to phenols and sugars has been developed. • The use of Ppy/AuNPs as electron mediator improves the performance of the sensors. • The bioET is able to predict the IPT and sugar content of grapes. • The bioET is able to predict the IPT and alcoholic degree of wines. • The bioET can correlate the quality of grapes with that of wines obtained from them. Abstract A bioelectronic tongue (bioET) based on combinations of enzymes (tyrosinase and glucose oxidase) and polypyrrole (Ppy) or polypyrrole/AuNP (Ppy/AuNP) composites was build up and applied to the analysis and discrimination of musts and wines. Voltammetric responses of the array of sensors demonstrated the effectiveness of polymers as electron mediators and the existence of favorable synergistic effects between Ppy and the AuNPs. Using Principal Component Analysis and Parallel Factor Analysis it was possible to discriminate musts according to the °Brix and TPI (Total Polyphenol Index), and wines according to the alcoholic degree and TPI. Partial Least Squares provided good correlations between the bioET output and traditional chemical parameters. Moreover, Support Vector Machines permitted to predict the TPI and the alcoholic degree of wines, from data provided by the bioET in the corresponding grapes. This result opens the possibility to predict wine characteristics from the beginning of the vinification process. [ABSTRACT FROM AUTHOR]

Highlights • Tea quality was jointly detected by E-nose, E-tongue and E-eye. • The signals of E-nose, E-tongue and E-eye were fused for analysis. • PLSR, SVM and RF were applied for qualitative and quantitative assessment. • The efficiency of the fusion signals outperformed that of independent signals. • RF based on the fusion signals performed perfectly in tea quality detection. Abstract Electronic nose (E-nose), electronic tongue (E-tongue) and electronic eye (E-eye) combined with chemometrics methods were applied for qualitative identification and quantitative prediction of tea quality. Main chemical components, such as amino acids, catechins, polyphenols and caffeine were measured by traditional methods. Feature-level fusion strategy for the integration of the signals was introduced to integrate the E-nose, E-tongue and E-eye signals, aiming at improving the performances of identification and prediction models. Perfect results with an accuracy of 100% were obtained for qualitative identification of tea quality grades, based on fusion signals by support vector machine and random forest. Quantitative models were established for predicting the contents of the chemical components based on independent electronic signals and fusion signals by partial least squares regression, support vector machine and random forest. Random forest based on the fusion signals achieved the best performance in predicting the concentration of those chemical components. [ABSTRACT FROM AUTHOR]

Highlights • Bitter peptide fraction had more positive charges, but less umami peptide residues. • HPH peptide fractions significantly inhibited quinine bitterness. • The least bitter peptide fractions had the most bitter-inhibitory effect. • HPH peptides are the blockers of human T2R4, T2R7, and T2R14. • HPH fraction is a rich T2R antagonist source. Abstract Bitter sensation is mediated by various bitter taste receptors (T2Rs), thus T2R antagonists are actively explored. Our objective was to look for novel T2R blockers in hen protein hydrolysate (HPH). We screened the least bitter HPH fractions using electronic tongue, and analyzed their peptide sequences and calcium mobilization in HEK293T cells expressing T2Rs. The results showed that the HPH fractions with higher bitterness intensity had higher hydrophobicity, more hydrophobic amino acids, and more positively charged peptides, but fewer known umami peptides. The peptide fractions from the least bitter HPH fraction significantly inhibited quinine bitterness (P < 0.05), and also significantly inhibited quinine- or diphenhydramine-dependent calcium mobilization of HEK293T cells expressing human T2R4, T2R7, or T2R14 (P < 0.05). Among them, the first eluted (least bitter) peptide fraction showed the strongest bitter-inhibitory effect. In conclusion, HPH peptides are the blockers of T2R4, T2R7, and T2R14. [ABSTRACT FROM AUTHOR]

Highlights • Identification of six novel umami and umami-enhancing peptides from PPIH. • RGENESEEEGAIVT was the first discovered umami and umami-enhancing tetradecapeptide. • Peptides could enhance the overall taste of chicken soup and soy sauce. • E-tongue has the potential to distinguish taste attributes of peptide solutions. Abstract Six novel peptides were separated from peanut protein isolate hydrolysate (PPIH) using ethanol precipitation and gel chromatography, and identified as DQR, NNP, EGF, EDG, TESSSE and RGENESEEEGAIVT by UPLC–ESI–QTOF–MS/MS. On the basis of sensory results, all peptides were perceived umami with threshold values from 0.39 to 1.11 mM and had umami-enhancing abilities simultaneously with threshold values from 0.33 to 0.82 mM. RGENESEEEGAIVT was the first discovered tetradecapeptide with umami and umami-enhancing ability. The dose–response test revealed that umami-enhancing activities of identified peptides were different: TESSSE and RGENESEEEGAIVT imparted better umami intensity when equimolar monosodium glutamate (MSG) was added into 0.5 g/L MSG solution. Taste profile analyses of complex mixtures with/without synthetic peptides were determined by both electronic tongue and human panellists, suggesting that umami peptides influence multiple tastes and electronic tongue has the potential to replace sensory test to distinguish taste attributes of foods rich in peptides. [ABSTRACT FROM AUTHOR]

Highlights • Drying process effects on roasted coffee bean quality properties were measured. • Volatile and taste components were profiled by E-nose, E-tongue, and HS-SPME-GC-MS. • Three dimensional datasets plus statistical modelling clearly discriminated samples. • Heat pump drying best preserved volatiles, producing high quality dried coffee. Abstract In this study, room-temperature drying, solar drying, heat pump drying (HPD), hot-air drying, and freeze drying were applied to investigate the volatile profiles and taste properties of roasted coffee beans by using electronic nose, electronic tongue, and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results indicated that the drying process markedly affected pH, total titratable acidity, total solids, and total soluble solids. Significant differences existed among all samples based on drying method; and the HPD method was superior for preserving ketones, phenols, and esters. Principal component analysis (PCA) combined with E-nose and E-tongue radar charts as well as the fingerprint of HS-SPME-GC-MS could clearly discriminate samples from different drying methods, with results obtained from hierarchical cluster analysis (the Euclidean distance is 0.75) being in agreement with those of PCA. These findings may provide a theoretical basis for the dehydration of coffee beans and other similar thermo-sensitive agricultural products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Blood oranges had the potential to be sold in advance under cold storage. • Anthocyanin contents of unripe fruits were raised to or over that of ripe fruits under cold storage. • Enrichment of total anthocyanin contents was higher at 8 °C than at 4 °C of storage. • Unripe fruits (260–280 d after anthesis) stored at 8 °C had similar qualities to ripe fruits. To explore the optimal early harvest time similar to the ripe fruit qualities, the effects of storage temperatures on maturity indexes, weight losses, colour parameters, anthocyanin profiles, volatile and taste components of blood oranges at six different maturity levels were investigated. Total anthocyanin contents of cold-treated fruits increased to or exceed that of ripe fruits (0.24 ± 0.12 mg/100 g), and fruits harvested from 260 d and 280 d after anthesis shared similar individual anthocyanin profiles to ripe fruits during storage at 8 °C for 30 d and 20 d (III-30 d and IV-20 d groups), respectively. Moreover, comparative analyses of e-nose and e-tongue demonstrated the distances of volatile components and scores of taste attributes including sourness, saltiness, bitterness, sweetness, and umami in III-30 d and IV-20 d groups were close to that of ripe fruits, indicating that the fruits could be sold about 20 to 30 d ahead of the season. [ABSTRACT FROM AUTHOR]

The use of oak products as a cheaper alternative to expensive wood barrels was recently permitted in Europe, which led to a continuous increase in the use of oak chips and staves in winemaking. The feasibility of the potentiometric electronic tongue as a tool for monitoring the effects of wine maceration with oak chips was evaluated. Four types of commercially available oak chips subjected to different thermal treatments and washing procedures and their mixture were studied. Ethanolic extracts of the chips were analysed using electrospray mass spectrometry and 28 phenolic and furanic compounds were identified. The electronic tongue comprising 22 potentiometric chemical sensors could distinguish artificial wine solutions and Cabernet Sauvignon wine macerated with different types of oak chips, quantify total and non-flavonoid phenolic content, as well as the concentrations of added oak chips. Using measurements at two pH levels, 3.2 and 6.5, improved the accuracy of quantification. [ABSTRACT FROM AUTHOR]

Electronic nose and tongue sensors and chemometric multivariate analysis were applied to characterize and classify 7 Chinese robusta coffee cultivars with different roasting degrees. Analytical data were obtained from 126 samples of roasted coffee beans distributed in the Hainan Province of China. Physicochemical qualities, such as the pH, titratable acidity (TA), total soluble solids (TSS), total solids (TS), and TSS/TA ratio, were determined by wet chemistry methods. Data fusion strategies were investigated to improve the performance of models relative to the performance of a single technique. Clear classification of all the studied coffee samples was achieved by principal component analysis, K-nearest neighbour analysis, partial least squares discriminant analysis, and a back-propagation artificial neural network. Quantitative models were established between the sensor responses and the reference physicochemical qualities, using partial least squares regression (PLSR). The PLSR model with a fusion data set was considered the best model for determining the quality parameters. [ABSTRACT FROM AUTHOR]

[Display omitted] • The umami was significantly negative correlating with sourness in Douchi. • The richness was positively correlated with astrigent and after-astrigent in Douchi. • The arginine biosynthesis and glutamate metabolism pathway were enriched in Douchi. • Other than glutamate, the succinic acid play a more key role for umami in Douchi. • The lactic acid was the key sour metabolite in LY, and YJ, as the l -malic acid in YC. Douchi is a traditional famous seasoning in China. This study adopted electronic tongue and metabolomics to analyze the taste characteristics and taste active compounds of 12 samples from three most famous types of Douchi (Liuyang Douchi, Yangjiang Douchi, Yongchuan Douchi). Thirty-six differential metabolites mainly enriched from the arginine biosynthesis were identified among these Douchis. Umami and bitterness are considered as two taste that bring positive and negative perceptions for Douchi. The succinic acid was found to be responsible for the umami in LY, YJ and YC Douchi, with the TAVs of 2054, 643, 174, respectively, rather than the glutamic acid and aspartic acid. The leucine was identified as the main metabolite for bitterness, with the TAVs of 9, 9, 7 respectively. KEGG enrichment analysis found that the umami, sourness and saltiness might be related to alanine, aspartate and glutamate metabolism and the bitterness might be related to aminoacyl-tRNA biosynthesis pathway. [ABSTRACT FROM AUTHOR]

• Low isoelectric of umami peptide led to TMC4 to enhance salty taste. • Ten umami peptides were found to be the salt - reducing peptides. • Lys568, Trp145, Tyr565, Arg151, and Gln155 were found in umami peptide and TMC4. To explore the saltiness enhancement effect and mechanism of umami peptides, umami peptides from Ruditapes philippinarum and ham were mixed with NaCl and determined using electronic tongue, sensory evaluation, and the aroma chicken model (ACM), then transmembrane channel-like protein 4 (TMC4) receptor was constructed for molecular docking. The results showed that KEMQKN, NGKET, RGEPNND, AHSVRFY, LSERYP, NRTF, TYLPVH, EV, AGAGPTP, and GPAGPAGPR had saltiness enhancement effect, which could be increased to 0.4–0.6 % NaCl salty taste in 0.3 % NaCl. Under neutral conditions (pH6.5), most umami peptides were in negative ion state which may be the main reason that umami peptides could bind to the TMC4 receptor and enhance saltiness. The lowest docking energy was −113.325 kcal/mol among 10 peptides and the active sites Lys568, Trp145, Tyr565, Arg151, and Gln155 in TMC4 may play a key role. Thus, this study provides basic theory and data for salt-reduction strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extra hydrophobic group onto aromatic ring did not show impact on sweet inhibition. • Structured carbon chain between molecular ring and carboxylic group manipulated sweet inhibition. • Electronic tongue may highlight a potential to perceive sweetness inhibitory effect. Lactisole is a potent sweetness inhibitor for alleviating the over-sweet problem in food. For investigating the sweetness inhibition mechanism of lactisole, seven derivatives were synthesized and their structure was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and mass spectrometry for confirming the modification on aromatic ring and carboxylic acid. An evaluation method for sweetness inhibition was developed using the electronic tongue, and the results revealed that the introduction of hydrophobic groups onto aromatic ring of lactisole did not improve the inhibitory activity. A certain branching and length of carbon chain between the aromatic ring and the carboxylic group were presumably important for inhibitory function. The plausible interpretation is that the structured carbon chain may influence the spatial position of carboxylic group during the interaction between the inhibitors and the receptor. A potent mechanism for regulating sweetness inhibition of the compounds based on their corresponding structural characteristics is proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • We clarified the differences between tank and traditional fermentation. • Thirty-six markers for the end of fermentation of Liupao tea were identified. • Thirty-four biomarker metabolites were significantly correlated with taste quality. Liupao tea is a dark tea with unique quality. Semi-finished Liupao tea with two different fermentation processes (traditional/tank) was analyzed to explain the chemical characteristics and taste quality. The content change rate of polyphenols, flavonoids, and theabrownin in traditional fermentation was approximately twice that in tank fermentation. Electronic tongue revealed that bitterness and astringency increased, whereas aftertaste-astringency decreased after fermentation. 36 compounds were identified as the biomarkers responsible for the metabolic changes caused by fermentation with significant decrements in catechins, catechin gallate, and α, α-trehalose, and significant increments in gallic acid content (VIP > 3; P < 0.05). In addition, 26 metabolites were identified to distinguish between tank and traditional fermentation, with correlation analysis indicating that catechin gallate, epicatechin and gallic acid accounting for the differences in taste between the two processes. This study provides a comprehensive insight into the chemical composition and sensory quality of different Liupao tea fermentations. [ABSTRACT FROM AUTHOR]

• Metabolite variation in two species of chaya leaves was described. • Young chaya leaves exhibited high umami taste intensity. • l -glutamic acid and 5′-adenosine monophosphate accumulated in young leaves. • Quinic acid, trigonelline, and other small peptides are novel umami compounds. Chaya (Cnidoscolus chayamansa and C. aconitifolius) is a fast-growing medicinal plant, and its leaves exhibit a strong umami taste. Here metabolite variation and umami-related compounds in the leaves of two chaya species were determined using a multiplatform untargeted-metabolomics approach, electronic tongue, and in silico screening. Metabolite profiles varied between the leaves of the two species and among leaf maturation stages. Young leaves exhibited the highest umami taste intensity, followed by mature and old leaves. Partial least square regression and computational molecular docking analyses revealed five potent umami substances (quinic acid, trigonelline, alanyl–tyrosine, leucyl–glycyl–proline, and leucyl–aspartyl–glutamine) and three known umami compounds (l -glutamic acid, pyroglutamic acid, and 5′-adenosine monophosphate). The five substances were validated as novel umami compounds using electronic tongue assay; leucyl–glycyl–proline exhibited synergism with monosodium glutamate, thereby enhancing the umami taste. Thus, substances contributing to the taste of chaya leaves were successfully identified. [ABSTRACT FROM AUTHOR]

The quality changes of RJ at different storage conditions are evaluated from various perspectives, including non-target volatile compound profiling, multi-index (physicochemical parameters and flavor characteristics), and multi-technology (HS-SPME-GC/MS, electronic nose, and electronic tongue) integration. [Display omitted] • A total of 37 volatile compounds in royal jelly are identified using HS-SPME-GC–MS. • Seven volatile compounds contribute largely to the overall flavor of royal jelly. • Electronic nose/tongue exhibit useful value in the quality control of royal jelly. • Combination of multiple methods enhance the evaluation of royal jelly quality. Royal jelly (RJ) is known for its unique flavor and nutritional value. However, the flavor changes of RJ during storage remain unclear. In this work, the flavor profiles of RJ during storage were evaluated by using headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with both electronic nose and electronic tongue analyses. Results revealed that the moisture, water-soluble protein, and whiteness were changed significantly at 25 °C. The holistic variation of RJ flavor exhibited evident distinction based on principal component analysis with electronic nose and electronic tongue. Among the total of 37 volatile compounds identified in RJ, the octanoic acid showed the highest contents of 47.61 % at 25 °C in 21 d. Seven volatile compounds, i.e., 2(3H)-furanone,5-butyldihydro-, 2-heptanone, trans -β-ocimene, 2-nonen-4-one, 2-nonanone, methyl benzoate, and 2-octenoic acid (E), contributed largely to the typical overall flavor of RJ. This work provides an improved understanding of the flavor change of RJ during storage. [ABSTRACT FROM AUTHOR]

• Four umami peptides were firstly screened from wild Lactarius volemus (Fr.). • The umami threshold of EVAEALDAPKTT was 0.0625 mg/mL. • Glu217, Glu148 and Glu45 in T1R3 subunit were key binding sites for the peptides. 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. [ABSTRACT FROM AUTHOR]

Seventeen edible mushrooms commercially available in Korea were analysed for their umami taste compounds (5′-nucleotides: AMP, GMP, IMP, UMP, XMP; free amino acids: aspartic, glutamic acid) and subjected to human sensory evaluation and electronic tongue measurements. Amanita virgineoides featured the highest total 5′-nucleotide content (36.9 ± 1.50 mg/g), while monosodium glutamate-like components (42.4 ± 6.90 mg/g) were highest in Agaricus bisporus . The equivalent umami concentration ( EUC ) ranged from 1.51 ± 0.42 to 3890 ± 833 mg MSG/g dry weight; most mushrooms exhibited a high umami taste. Pleurotus ostreatus scored the highest in the human sensory evaluation, while Flammulina velutipes obtained the maximum score in the electronic tongue measurement. The EUC and the sensory score from the electronic tongue test were highly correlated, and also showed significant correlation with the human sensory evaluation score. These results suggest that the electronic tongue is suitable to determine the characteristic umami taste of mushrooms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Olive oils extracted at industry without or with water addition during milling step. • All cv. Arbequina oils classified as extra virgin olive oil. • Extraction without water addition increased ripe fruity sensation. • Extraction without usual water addition increased the secoiridoids contents. • Water addition level influenced oils composition allowing E-tongue discrimination. At olive oil industrial extraction, water addition is a practice overcoming the formation of thick pastes. The effect of water addition (0 to 6.2%, kg added water /kg olives), during the industrial milling of cv. Arbequina olives, on the oils' chemical-sensory quality, was evaluated. Despite the extra virgin olive oil classification, compared with the water incorporation (1.2–6.2%), extraction without water addition resulted into oils that showed less primary oxidation (lower peroxide values and K 232), greater total phenolic content (+12–22%) and higher oxidative stability (+22–31%). No water addition increased the oils secoiridoids content (+5–13%), mainly oleacein (+27–79%). Oils extracted without water addition had a more intense ripe fruity sensation (≥ +11%) but lower fruit intensities (at least −4%). Thus, the quality and stability of the cv. Arbequina oils can be favoured if extracted without adding water during the olives industrial milling. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aroma and taste of peanut butter were analyzed using electronic sensing. • Four different pretreatments were applied in the production of the butter. • Microwave treatment resulted in a stronger nutty aroma. • Radio-frequency treatments resulted in a finer texture. • Explosion puffing did not result in any improvements to the taste or aroma. Currently, the effect of different pretreatments (i.e., radio frequency (RF), explosion puffing (EP), microwave (MW) and oven heating (OH)) on the flavor characteristics of peanut butter is unclear. Consequently, this study identified volatile aroma and non-volatile taste using HS-SPME/GC–MS combined with the use of an electronic nose, electronic tongue, and sniffing. 53 volatile compounds in four peanut butters were identified, MW-treated samples exhibited the most aroma-active compounds (43), followed by samples treated using OH (42), EP (38) and RF (21). Different pretreatment resulted in significant flavor differences in the aroma and taste. The peanut butter under MW pretreatment had a strongest nutty notes among the treatments. RF methods yielded smaller particle sizes and better texture compared to conventional OH. However, instantaneous heating using EP did not result in improvements to the aroma or taste. A combination of MW and RF may improve the flavor quality of peanut butter. [ABSTRACT FROM AUTHOR]

Antioxidant properties of juices of newly bred and known blueberry ( Vaccinium corymbosum ) genotypes and wild bog blueberry ( Vaccinium uliginosum ) were evaluated by ABTS + scavenging capacity (RSC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total phenolic content (TPC) and total anthocyanin content (TAC) assays. TPC varied in the range of 0.85–2.81 mg gallic acid equiv./mL, RSC, FRAP and ORAC values were 6.38–20.9, 3.07–17.8 and 4.21–45.68 μmol Trolox equiv./g, respectively. New blueberry genotypes and bog blueberry demonstrated stronger antioxidant properties and TAC than other studied genotypes. The content of quinic (203–3614 μg/mL), chlorogenic (20.0–346.8 μg/mL) acids and rutin (0.00–26.88 μg/mL) measured by UPLC/ESI-QTOF-MS varied depending on the genotype. Juices were evaluated by electronic tongue; PCA score plot showed that the method discriminates different genotypes although some juice samples were located very closely and overlapping. Significant differences were observed between L ∗ , a ∗ , b ∗ colour parameters of some genotypes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antler fungus had the highest umami taste intensity. • Umami amino acids and nucleotides enhanced the salty intensity of NaCl. • Antler fungus enzymatic hydrolysate increased the salty intensity of NaCl. 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. [ABSTRACT FROM AUTHOR]

Highlights: [•] Correlation between umami taste and analytical measurements is studied. [•] Electronic tongue and near-infrared spectroscopy are used as instrumental methods. [•] Both techniques are promising as method for preliminary screening of umami products. [•] Electronic tongue signals show a better correlation with the umami attribute. [•] Fusion of the data provides only a small improvement of the results. [Copyright &y& Elsevier]

Highlights: [•] Our electronic panel discriminates wines with different polyphenolic and oxygen content. [•] The signals of the e-panel correlate well with oxygen level, polyphenols and colour values. [•] The combined use of an e-nose and an e-tongue improves the quality of the predictions. [Copyright &y& Elsevier]

Highlights: [•] E-tongue discriminated makgeollis into three groups based on the amino acid content of the rice. [•] Sweetness, saltiness, and umami were initially detected, followed by bitterness, then sourness. [•] E-tongue predicted most of the sensory attributes other than bitterness with relatively good r 2. [Copyright &y& Elsevier]

• Collagen peptides from grass carp were glycated by glucosamine to prepare Maillard reacted peptides. • The degree of Maillard reaction of collagen peptides was relatively low. • Thermal degradation and crosslinking simultaneously occurred. • Glycation of collagen peptides by glucosamine contributed to the salt-taste enhancing property. Reducing salt intake, as one of the most cost-effective approaches, is congruent with improved population health. Grass carp skin collagen was subjected to enzymatic hydrolysis and ultrafiltration, followed by glucosamine-induced Maillard reaction to prepare Maillard-reacted peptides. Their color, free amino acid and peptide size distribution were analyzed, while UV and fluorescence spectroscopy were utilized to characterize the progress of Maillard reaction. The salt taste-enhancing effect of Maillard-reacted peptides was investigated via sensory analysis and electronic tongue. LC–MS/MS was employed to analyze the glycation sites of Maillard-reacted peptides. The results indicated that the degree of Maillard reaction was relatively low, and thermal degradation and crosslinking simultaneously occurred. Maillard-reacted peptides exhibited a significant salt taste-enhancing effect, which may be attributed to the glucosamine-induced glycation confirmed by LC–MS/MS analysis. The current study provides a theoretical basis for preparation of salt taste-enhancing peptides and their future application to reduce salt content of formulated foods. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new methodology based on multisensory system for the analysis of beer. [•] Electronic tongue using an array of potentiometric ion selective electrodes (ISEs). [•] Qualitative and quantitative examples of electronic tongue applications. [•] Discrimination of different beer classes by means of an LDA model. [•] Prediction of alcohol by volume (abv) content by means of an ANN model. [Copyright &y& Elsevier]

Abstract: Mineral, spring and tap water samples of different geographical origins (7 classes) were distinguished by various methods, such as sensory evaluation, electronic tongue measurement, inductively coupled plasma atomic emission spectroscopy and ion chromatography. Samples from the same geographical origin were correctly classified by chemical analysis and electronic tongue (100%), but it was found that only 80% classification rate can be achieved by sensory evaluation. Different water brands (different brand names) from the same geographical origin did not show definite differences, as expected. Forward stepwise algorithm selected three chemical parameters namely, chloride (Cl−), sulphate (SO4 2−) and magnesium (Mg) content and two electronic tongue sensor signals (ZZ and HA) to discriminate according to the geographical origins. [Copyright &y& Elsevier]

Abstract: To clarify the key flavour peptides that account for the cooked taste of puffer fish, this study was performed to examine flavour peptides extracted from the flesh of puffer fish (Takifugu obscurus). Peptides fractions (P1, P2, P3, P4 and P5) were purified from an aqueous extract of T. obscurus muscle by ultrafiltration and Sephadex G-15 gel filtration chromatography (GFC). P2 was further fractionated into P2a, P2b, and P2c by reverse phase high performance liquid chromatography (RP-HPLC). Fraction P2b elicited umami and sweet taste. The amino acid sequence of P2b subfraction was identified as Tyr-Gly-Gly-Thr-Pro-Pro-Phe-Val (836.4Da) by matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF/TOF MS/MS). Hydrophilic amino acids residues Tyr, Gly, Gly, Thr, and Phe are likely to contribute to the umami and sweet taste of this octapeptide. The results of this study suggest this peptide is one of important components of the ‘mellowness’ and ‘tenderness’ taste of the T. obscurus. [Copyright &y& Elsevier]

Abstract: A poly(3,4-ethylendioxythiophene) modified electrode has been considered as a potentially useful amperometric sensor to use either alone or in the frame of a set of sensors bearing complementary information, i.e. within an electronic tongue. The sensor is proposed in blind analysis of red wines, for classification and calibration purposes. The data obtained from voltammetric measurements have been treated using partial least squares analysis. A calibration procedure has been performed to correlate results from analyses of wines, executed with traditional analytical methods, with the corresponding voltammetric responses. Moreover, classification models of the wine samples, based on quantitative parameters and qualitative information about origin and variety, have been built. The developed electrochemical sensor also allows the fast identification of samples exceeding threshold limits of meaningful parameters for quality control in the wine industry, such as SO2, colour intensity and total polyphenols. The application of the system within a sensor array (electronic tongue) to fast pre-screening routine control procedure is proposed. [Copyright &y& Elsevier]

Abstract: This work describes the correlation found along 10days between potentiometric measurements obtained by using an electronic tongue and the variation in certain physicochemical, microbial and biochemical parameters measured on a whole piece of pork loin stored under refrigeration. The electronic tongue consists of a set of six electrodes made of Au, Ag, Cu, Pb, Zn and C, and a reference electrode. Through the use of various multivariate analysis techniques, such as: PCA and two types of artificial neural networks (i.e. multilayer perceptron (MLP) and fuzzy ARTMAP) it was found that it is possible to determine the time elapsed in relation to the degradation of the loin by using simple potentiometric measurements. Additionally, in the same pork sample used to measure redox potentials with the electronic tongue, the following parameters were also determined; pH, microbial count, concentrations of inosine 5′-monophosphate (IMP), inosine (Ino) and hypoxanthine (Hx). Through the use of PLS analysis, it was found a rather good correlation between pH and the potentiometric data. Also a remarkable correlation was observed between the measures carried out with the electronic tongue and the so-called K-index that simultaneously measures the variation in the adenosine triphosphate (ATP) degradation products. These results suggest that this simple, or a similar electronic tongue, could be useful for the undemanding qualitative or semi-quantitative evaluation of freshness in meat samples in a wide range of situations. [ABSTRACT FROM AUTHOR]