Umami Amino Acids Research Articles

Detection of structural variants linked to mutton flavor and odor in two closely related black goat breeds

BackgroundMutton quality is closely related to genetic variants and gene expression alterations during growth and development, resulting in differences in nutritional values, flavor, and odor.ResultsWe first evaluated and compared the composition of crude protein, crude fat, cholesterol, amino acid (AA), and fatty acid (FA) in the longissimus dorsi muscle of Guizhou black goats (GZB, n = 5) and Yunshang black goats (YBG, n = 6). The contents of cholesterol and FA related to odor in GZB were significantly lower than that in YBG, while the concentrations of umami amino acids and intramuscular fat were significantly higher in GZB. Furthermore, structural variants (SVs) in the genomes of GZB (n = 30) and YBG (n = 11) were explored. It was found that some regions in Chr 10/12/18 were densely involved with a large number of SVs in the genomes of GZB and YBG. By setting FST ≥ 0.25, we got 837 stratified SVs, of which 25 SVs (involved in 12 genes, e.g., CORO1A, CLIC6, PCSK2, and TMEM9) were limited in GZB. Functional enrichment analysis of 14 protein-coding genes (e.g., ENPEP, LIPC, ABCA5, and SLC6A15) revealed multiple terms and pathways related with metabolisms of AA, FA, and cholesterol. The SVs (n = 10) obtained by the whole genome resequencing were confirmed in percentages of 36.67 to 86.67% (n = 96) by PCR method. The SVa and SVd polymorphisms indicated a moderate negative correlation with HMGCS1 activity (n = 17).ConclusionThis study is the first to comprehensively reveal potential SVs related to mutton nutritional values, flavor, and odor based on genomic compare between two black goat breeds with closely genetic relationship. The SVs generated in this study provide a data resource for deeper studies to understand the genomic characteristics and possible evolutionary outcomes with better nutritional values, flavor and extremely light odor.

Changes in the Objective Indices Related to Meat Quality of Porcine Longissimus Dorsi Induced by Different Thawing Methods.

The quality of frozen pork is adversely affected upon thawing. In this study, the influence of various thawing methods for frozen pork, including cold water (18 °C), room temperature (18 °C), and refrigeration (4 °C) thawing, on physicochemical and nutrient substances were examined. The pork samples (a Chinese local breed: Anqing six-end-white pigs), which were thawed through the above conditions, were compared with controls (fresh porcine longissimus dorsi). Analyses were carried out to determine porcine longissimus dorsi shear force, pH value, crude protein content, antioxidant capacity, amino acid content, and fatty acid content. The results indicated that the shear force, pH value, crude protein content, total antioxidant capacity (T-AOC), and total superoxide dismutase (T-SOD) content of the porcine longissimus dorsi muscle significantly decreased via the three thawing methods compared with the control group (p < 0.05). However, malondialdehyde (MDA) content, intramuscular fat content, inosinate and cholesterol content, essential amino acid content, and umami amino acid proportion in the cold thawing group were not significantly different from the control group (p > 0.05), but there were significant differences between the other two groups. The MDA content of the air thawing and hydrostatic thawing groups significantly increased compared with the control group (p < 0.05), with it being 42.6% and 50.8% higher than the control group, respectively. In addition, the monounsaturated fatty acid content in the pork subjected to the three thawing methods significantly increased compared with the control group (p < 0.05), and the monounsaturated fatty acid content after cold thawing and hydrostatic thawing increased by 18.2% and 21.6%, respectively. In conclusion, refrigeration had less influence on the quality of the Anqing six-end-white pork and was the most suitable thawing method. This study provides a theoretical reference for frozen pork preservation for improving food quality and availing its economic benefits.

Comparing effects of tangerine-peel (Citrus reticulata Blanco) age and concentration on deep-fried rabbit meat: Impact on heterocyclic aromatic amines, amino acids, and flavor compound formation

Many nutritional experts recommend rabbit meat as a high-protein source. However, the high temperatures used to prepare deep-fried rabbit meat (DFRM) typically produce numerous heterocyclic aromatic amines (HAAs), a class of substances with carcinogenic risks. In this study, we chromatographically evaluate changes in the volatile compounds, amino acids, and HAAs in DFRM while employing tangerine peel (TP) as an additive. A total of 35 volatile organic compounds are detected in the TP, which increase the concentrations of sweet and umami amino acids in the DFRM. Remarkably, the TP substantially inhibits the IQ-type HAAs, particularly MeIQ, MeIQx, 4,8-DiMeIQx, and PhIP, which are produced during deep frying. Correlation analyses reveal that the histidine, aldehydes, and alcohols are strongly and positively correlated (P < 0.001) with the MeIQ, MeIQx, 4,8-DiMeIQx, and PhIP production. This study offers innovative and natural approaches for reducing HAA formation during the frying of rabbit meat.

Evaluation of physicochemical and flavor characteristics and primary on lipid oxidation of crucian carp under different cooking methods

This study aimed to reveal the effects of steaming, frying and boiling on the sensory and quality of the cooked crucian carp. 46, 27 and 37 volatiles were detected in the steamed fish, fried fish (FF) and boiled fish (BF), respectively, of which 7 were identified as the key volatiles. Compared with the BF and FF, the SF was richer in esters, aldehydes, alkenes and the kinds and contents of the key volatiles. The contents of moisture and crude protein were the highest in the SF. The FF exhibited the most distinctive aroma profile, much possibly associated with the highest thiobarbituric acid reactive substances (TBARS) value observed in the FF. The content of total free amino acid in the BF was the lowest while the content of umami amino acid content in the SF was the highest (p < 0.05). The nutrition of fatty acids was highest in the SF due to its highest ƩUFA/ƩSFA ratio. PLS-DA analysis showed that SF was positively correlated with the most key volatiles and several free fatty acids. These results indicated that the flavor and nutrition of SF were the highest, providing appropriate cooking methods of crucian carp for the standardized production of bean paste fish.

Metabolomics ravels flavor compound formation and metabolite transformation in rapid fermentation of salt-free fish sauce from catfish frames induced by mixed microbial cultures

This study demonstrates that the co-inoculation with Lactiplantibacillus plantarum, Pichia fermentans and Staphylococcus saprophyticus accelerates catfish frame fish sauce fermentation. Over a 3-day period, significant changes occurred in physicochemical properties, microbial profiles, flavor compounds, and metabolomic spectra. Notable increases in acidity coupled with decreases in glucose underscored the robust environmental adaptability of the employed microorganisms. A reduction in total amino acids, alongside a rise in umami amino acids, suggested flavor enhancement. GC–MS analysis identified 40 key volatile compounds, with esters and aldehydes crucial for aroma development. UPLC-QTOF-MS-based untargeted analysis identified 934 metabolites, with 377 differential metabolites being vital (VIP > 1.5, P < 0.05), including amino acids, peptides, organic acids, nucleic acids, and fatty acids. Metabolites linked to amino acid metabolism, particularly phenylalanine and arginine, were associated with fermentation duration. These findings offer a theoretical basis for optimizing flavor and quality in fish sauces from fish by-products through accelerated fermentation.

Comparison of Different Deodorizing Treatments on the Flavor of Paddy Field Carp, Analyzed by the E-Nose, E-Tongue and Gas Chromatography-Ion Mobility Spectrometry.

Changes in the flavor and taste profiles of Paddy Field Carp after deodorization with perilla juice (PJ), cooking wine (CW) and a mixture of the two (PJ-CW) were analyzed using the E-nose, E-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), free amino acid analysis and taste nucleotide analysis. The E-nose and E-tongue revealed that deodorization reduced the content of sulfur-containing compounds, enhanced umami, bitterness, sourness and astringency, and decreased saltiness. PCA and OPLS-DA analysis successfully distinguished between the effects of the treatments. Free amino acids increased from 8777.67 to 11,125.98 mg/100 g and umami amino acids increased from 128.24 to 150.37 mg/100 g after PJ-CW deodorization (p < 0.05). Equivalent umami concentration (EUC) comparisons showed that PJ-CW treatment produced the greatest synergistic umami enhancement (to 3.15 g MSG equiv./100 g). GC-IMS detected 52 aroma compounds; PJ treatment produced the greatest diversity of aldehydes, including heptanal, nonanal, hexanal, 3-methylbutanal, (E)-2-heptenal and (E,E)-2,4-heptadienal. The total content of volatile flavor compounds was the highest after PJ-CW treatment, and the content of many characteristic flavor substances (3-hydroxy-2-butanone, benzaldehyde, 5-methyl-2(3H)-furanone) increased. These findings provided a theoretical basis for the further development of deodorization methods for Paddy Field Carp.

Effects of different thermal methods and degrees on the flavor of channel catfish (Ictalurus punctatus) fillets: Fatty acids, volatile flavor and taste compounds

The effects of different thermal processing conditions on the flavor profiles of channel catfish were evaluated in terms of fatty acids, volatile flavor and taste compounds using steaming, boiling, roasting, and microwaving with different degrees. After thermal processing, 72 volatile organic compounds were detected, including 20 hydrocarbons, 5 ketones, 20 aldehydes, 7 heterocyclic compounds, 12 alcohols and others. Meanwhile, the contents of unsaturated fatty acids like oleic acid and linoleic showed a significant decline due to their heat-sensitive properties. With regard to taste compounds, thermal processing contributed to umami amino acids and free nucleotides conversion, with the initial glutamate and IMP contents of 15.87 and 164.91 mg/100 g in raw samples mainly increasing by 2.8–10.3 and 14.4–105.5 mg/100 g in processed ones. Compared to other methods, microwaving had limited effects on flavor compounds, and steaming and roasting had better performance to improve the flavor complexity of channel catfish.

Influence of Different Feed Particle Sizes on the Growth Performance and Nutrition Composition in Crayfish, Procambarus clarkii Larvae.

A suitable feed size has a positive effect on animal feeding. For aquatic larvae, the correct feed size is very important for their growth. This experiment analyzed and compared the effect of different particle sizes of feed for larval stages on the growth performance, whole body composition, and muscle amino acid and fatty acid composition of crayfish. Five larval crayfish diets of different particle sizes, namely < 0.40 mm (Group A, control group), 0.40-0.50 mm (Group B), 0.71-0.85 mm (Group C), 0.90-1.00 mm (Group D) and 1.5 mm (Group E), were fed to 2000 crayfish (initial weight 0.0786 ± 0.0031 g) for 100 d. The results showed that as the particle size increased, final weight, weight gain (WG, p = 0.001) and specific growth rate (SGR, p = 0.000) of the crayfish tended to increase and then leveled off, with the control group being the lowest. The feed conversion ratio (FCR, p = 0.000) showed a decreasing and then equalizing trend with increasing particle size, but there was no significant difference between the groups except the control group. Broken-line regression analysis showed that the critical values for the appropriate particle feed size for crayfish larvae were 0.55 mm and 0.537 mm using SGR and FCR as indicators. Groups B, C and D had the highest crude protein content and were significantly higher than the control group (p = 0.001). Group E had the highest umami amino acid (UAA) and was significantly higher than the control group (p = 0.026). The content of isoleucine (Ile, p = 0.038) and phenylalanine (Phe, p = 0.038) was highest in group C and significantly higher than in the control group. Through principal component analysis, groups C and D were shown to contain leucine (Leu), glutamic (Glu), methionine (Met), valine (Val), histidine (His), Phe, and Ile levels significantly induced. The content of linoleic acid (C18:2n6, p = 0.000), linolenic acid (C18:3n3, p = 0.000), saturated fatty acid (SFA, p = 0.000), monounsaturated fatty acid (MUFA, p = 0.001), polyunsaturated fatty acid (PUFA, p = 0.000) and n-6 PUFA (p = 0.000) in group C was the highest and significantly higher than the control group. Principal component analysis showed that group C significantly induced the levels of C18:2n6, C18:3n3, DHA, EPA, n-3 PUFA and n-6 PUFA in muscle. Therefore, our results suggest that appropriate feed particle size can improve the growth performance and nutrient composition of crayfish. Based on the broken-line regression analysis of SGR and FCR, the critical values of optimal particle size for crayfish are 0.55 mm and 0.537 mm, and when the particle size exceeds these critical values (not more than 1.5 mm commercial feed), growth performance and FCR of the crayfish are no longer changed. Nevertheless, group C has high protein and low lipid content, as well as better nutrition with amino acids and fatty acids. Overall, combined with growth performance and nutrient composition, it is recommended that the particle size of the diet at the larval stage for crayfish is between 0.71 and 0.85 mm.

Sequential Enzymatic Hydrolysis and Ultrasound Pretreatment of Pork Liver for the Generation of Bioactive and Taste-Related Hydrolyzates.

In the study of protein-rich byproducts, enzymatic hydrolysis stands as a prominent technique, generating bioactive peptides. Combining exo- and endopeptidases could enhance both biological and sensory properties. Ultrasound pretreatment is one of the most promising techniques for the optimization of enzymatic hydrolysis. This research aimed to create tasteful and biologically active pork liver hydrolyzates by using sequential hydrolysis with two types of enzymes and two types of ultrasound pretreatments. Sequential hydrolyzates exhibited a higher degree of hydrolysis than single ones. Protana Prime hydrolyzates yielded the largest amount of taste-related amino acids, enhancing sweet, bittersweet, and umami amino acids according to the Taste Activity Value (TAV). These hydrolyzates also displayed significantly higher antioxidant activity. Among sequential hydrolyzates, Flavourzyme and Protana Prime hydrolyzates pretreated with ultrasound showed the highest ferrous ion chelating activity. Overall, employing both Alcalase and Protana Prime on porcine livers pretreated with ultrasound proved to be highly effective in obtaining potentially tasteful and biologically active hydrolyzates.

Enhancing the flavor profile of strong-flavored green tea from Sichuan: Evaluation and optimization study

This study evaluated seven taste subfactors of 64 green teas from Sichuan province and categorized them into three types: fresh and mellow (FM), strong and thick (ST), and fresh and strong (FS). The FM-type showed excellent freshness and sweetness, while the ST-type exhibited bitterness, astringency, and strength. Component analysis showed higher water extract and tea polyphenols in the ST-type, with the soluble sugar content correlating positively with taste strength but not sweetness, highlighting the complexity of flavor perception. More exhaustively, we used targeted metabolomics to examine the relevant constituent fractions. The levels of epigallocatechin gallate, epicatechin gallate, epigallocatechin, epicatechin, dihydromyricetin and rutin were highest in ST, and positively correlated with bitterness and astringency. Umami amino acids were found mostly in FM, and were positively correlated with freshness. To optimize the taste quality of ST green tea, two methods were investigated: tea bag confinement leaching and aroma enhancement. Both methods effectively reduced bitterness and astringency. Tea bag confinement leaching can be widely applied to enhance the utilization of summer tea raw materials and elevate the sensory quality of middle- and low-grade green teas. While promising for seasoned tea flavor enhancement and bitter suppression, the aroma enhancement technique requires further research.

Effects of dietary β‐carotene on color and flavor quality of ovaries in adult female Chinese mitten crab (Eriocheir sinensis)

AbstractThis study aimed to investigate the effects of adding different levels (0, 50, 100, 200 and 300 mg/kg) of dietary β‐carotene on the color and flavor quality of adult female E. sinensis ovaries. Adding moderate amount of β‐carotene to the feed could regulate the distribution of carotenoids, fatty acids, and free amino acids in the ovaries of E. sinensis, as well as increase the content of total carotenoids, total fatty acids, sweet and umami amino acids in the ovaries. The dietary β‐carotene have limited coloring effects and a significant impact on the flavor of the ovaries. During thermal process, the addition of 100 mg/kg β‐carotene could effectively promote formation of aroma precursors and generate more characteristic aroma components (2‐methylbutanal, 3‐methylbutanal, hexanal, benzaldehyde, methylpyrazine). However, excessive β‐carotene supplementation (300 mg/kg) led to adverse effects on physiological metabolism and flavor of E. sinensis ovaries. Considering both feed cost and quality improvement, β‐carotene supplementation at 100 mg/kg can be considered the optimal feed supplementation for adult female E. sinensis within a 70‐day rearing period to improve edible quality of ovaries.

Impact of Reducing Nitrogen Fertilizer with Biochar on Flavor Substance and Nitrogen Balance in Different Swollen-Stem-Mustard Varieties

Excessive application of nitrogen fertilizer in the swollen-stem mustard cultivation leads to a series of environmental and quality issues. It was reported that reducing nitrogen fertilizer with biochar could increase crop yield and reduce environmental risks. However, the effect of nitrogen reduction combined with biochar application on the flavor substances was rarely reported. Thus, two genetic stem mustard varieties (Yx: Yong’an xiaoye and Fz: Fuza No. 2), and four N treatments (control: 0 N kg/ha with biochar; N150: 150 N kg/ha with biochar, N300: 300 N kg/ha with biochar, and N450: 450 N kg/ha) were chosen to study the effects of nitrogen reduction combined with biochar on the flavor substance content of mustard stem, and N balance. The results showed that the residual soil inorganic N in N300 was lower by 37% than that in N450 (156.5 kg/ha) in Fz mustard soil, and lower by 33% in N150 than in N450 (163.1 kg/ha) in Yx mustard. The highest biomass of stem mustard tumors of Fz (35.4 × 103 kg/ha) and Yx (35.7 × 103 kg/ha) was in N300. The content of umami amino acids, sweet amino acids, and bitter amino acids of Yx and Fz stem was the highest in N450, and N300, respectively. After comprehensive consideration, the Fz was recommended to be planted in the Three Gorges Reservoir Area with N300.

Effects of different fermenters on the quality and flavour of fermented mandarin fish (Siniperca chuatsi)

SummaryIn this study, the effect of different fermenters on the quality and flavour of fermented mandarin fish was investigated via pH, salt content, moisture content, thiobarbituric acid, microbial community, free amino acids and volatile compounds. The results demonstrated that the inoculated fermentation effectively suppressed fish fat oxidation, resulting in significantly higher levels of umami amino acids in mandarin fish compared to the natural fermentation group (P &lt; 0.05). Additionally, certain bitter amino acids were also inhibited. Moreover, the total amino acid content of the mixed inoculated fermentation group was significantly elevated compared to other groups, reaching 300.21 ± 5.37 mg/100 g. The synergistic effect of free amino acids and flavour‐enhancing nucleotides significantly influenced the taste of the fermented fish, with the mixed inoculation fermentation group exhibiting a significantly higher Equivalent umami concentration (EUC) value compared to other groups, reaching 216.06 ± 20.13 mgMSG/100 g on the sixth day of fermentation. A total of 47 volatile compounds were detected by using headspace gas chromatography‐ion mobility spectrometry (HS‐GC‐IMS), and the results demonstrated that inoculated fermentation positively influenced the development of fish flavour, and mixed inoculated fermentation proved to be more effective. This study provides a theoretical foundation for the industrial production of fermented fish products and offers potential avenues for technical enhancement.

Understanding the correlation between formation of flavor compounds and dominant bacteria during Luoyang mung bean sour fermentation

To understand the change of the overall flavor component, including volatile compounds and free amino acid, Luoyang mung bean sour (LMBS) was investigated by gas chromatography-mass spectrometry (GC-MS) and automatic amino acid analyzer. The results showed that the beany flavor compounds, including hexanal, 2-hexenal, hexanol, and 1-octene-3-ol, significantly decreased or even disappeared. The concentration of esters and acids, represented by caproic acid and hexyl acetate, increased during LMBS fermentation. By detecting the free amino acids, it was found that the umami taste of glutamic acid (Glu) and aspartic acid (Asp) were the dominant amino acids. Among the 7 metabolites tested, lactic acid exhibited the highest concentration and continued to accumulate during fermentation. Leuconostoc, Enterobacter, Lactobacillus, Citrobacter Pediococcus, and Lactococcus were identified as the dominant bacterial groups that exhibited fluctuations during LMBS fermentation. Ultimately, Lactobacillus emerged as the dominant species. The network of Spearman correlation analysis was employed to uncover the relationship between bacterial community and flavor compounds during the fermentation of LMBS. For the dominant bacteria, Leuconostoc, Pediococcus, and Lactobacillus were positively correlated with acetic acid, lactic acid, citric acid, alcohol, sweet and umami amino acids, while negatively correlated with ketones alcohols and bitter amino acids.

Comparison of various drying methods on color, texture, nutritional components, and antioxidant activity of tumorous stem mustard

Exploring new dehydration technology can help to deal with the challenge of quality preservation and high salt waste brine problem in pickled mustard industry. In the current study, effects of vacuum freeze-drying (FD), heat pump drying (HPD), air-impingement jet drying (AIJD), and hot air drying (HD), on color, texture, nutritional component, and antioxidant capacity of tumorous stem mustard were determined. All drying methods significantly affected color and texture. The ascorbic acid (Vc), reducing sugar, protein, total phenolic content (TPC), ABTS, DPPH, and FRAP level of tumorous stem mustard were 123.20–768.74 mg/100 g, 2.49–17.90 g/100 g, 30.74–53.03 g/100 g, 1.98–4.13 mg gallic acid equivalent (GAE)/g, 1.42–8.28 mg Vc/g, 1.04–9.73 mg Vc/g, and 2.11–6.83 mg Vc/g, respectively. The content of individual phenolics were influenced by drying methods, and ferulic acid was determined as a major phenolic compound for all samples (8.15–65.43 μg/g). The content of total phenolic and monomeric polyphenols except for ferulic acid, positively correlated to their antioxidant activity. Furthermore, HD, FD, and AIJD were beneficial to promote the production of umami amino acids and reduce bitter amino acids, thus improving the flavor of tumorous stem mustard. The quality of tumorous stem mustard of FD was closest to that of fresh tumorous stem mustard. Overall, the drying technology is promising to replace the salt infiltration process to realize the dehydration of tumorous stem mustard in the manufacturing of pickled mustard.

Characterization of biodiversity and meat quality in Guizhou yellow cattle: Correlations among intrinsic factors

This study aimed to characterize meat quality diversity among Guizhou yellow cattle and investigate the correlations among intrinsic factors that affect beef quality. Various cuts including chuck roll, fore shank, topside, rib fingers, flank, brisket, and tenderloin were taken from the carcass of Sinan cattle, Guanling cattle, and the Simmental-Guanling crossbred cattle for meat quality comparisons. The results showed that meats of all three breeds displayed high water-holding capacity and desirable meat colors, but they were tough in texture. Variations among the breeds were identified, with Guanling cattle having darker meat than the crossbred cattle. The crossbreed had lower shear force indicating potential heterosis benefits, and possessed higher fat content. Guizhou yellow cattle were leaner and more abundant in protein and umami amino acids, potentially contributing to favorable flavor. The hierarchical cluster analysis and nutritional indices assessment implicated that the composition of fatty acids demonstrated a breed-specific effect in Guanling cattle, offering greater benefits in cardiovascular disease prevention. The increased quantity of vitamin A present in the majority of cuts from crossbred and Sinan cattle enhanced their nutritional value. By multivariate data analysis, we found that as the variations in physicochemical properties increased, the nutrient compositions in beef became more complex. Overall, this study demonstrated that meats from all three breeds were nutrient-balanced high-quality protein sources, although certain indexes may vary across cuts and breeds. These variations should be considered when developing breeding strategies in the future.

Effects of Different Carbon and Nitrogen Ratios on Yield, Nutritional Value, and Amino Acid Contents of Flammulina velutipes.

The carbon-to-nitrogen (C/N) ratio in the cultivation medium significantly influences the growth rate, vigor of mycelium, yield of fruiting bodies, and their nutritional composition. Recently, agricultural and forestry wastes have been increasingly used in cultivating Flammulina velutipes. However, systematic research on how these materials affect the nutritional and functional properties of the fruiting bodies is lacking. This study investigated the effects of different C/N ratios on F. velutipes cultivation. We evaluated the agronomic traits, nutritional composition, and flavor compounds of the fruiting bodies. Our findings reveal that an optimal C/N ratio of 27:1 in the composted substrates enhances the total yield of fruiting bodies, with 25.1% soybean straw as the primary raw material. This ratio also significantly increases the levels of crude protein, total amino acids, and essential amino acids in the fruiting bodies (p < 0.05). Fruiting bodies from the high-nitrogen (HN) treatment showed the highest content of umami amino acids and equivalent umami concentration value. Additionally, we employed an untargeted liquid chromatography-mass spectrometry (LC-MS)-based metabolomics approach to analyze the metabolite profiles of fruiting bodies cultivated in high-nitrogen (HN), medium-nitrogen (MN), and low-nitrogen (LN) substrates. We found that the carbon-nitrogen ratio can affect the flavor and quality of fruiting bodies by regulating amino acid biosynthesis and metabolism and other related pathways. Our results suggest that a C/N ratio of 27:1 offers numerous benefits for the cultivation of F. velutipes with comprehensive analyses and has promising application prospects.

A comparative study on the taste quality of whiteleg shrimp (Penaeus vannamei) under two different transportation strategies

The current study comprehensively investigated the impacts of simulated water-based transportation and waterless transportation on the taste attributes and nonvolatile taste components in shrimp muscle. The results of the electronic tongue revealed that the umami sensation increased while the sweetness decreased after transportation. The primary taste components of shrimp muscle from the various transportation groups were identified using two-dimensional correlation spectroscopy, including free amino acids, nucleotides, and organic acids. The highest equivalent umami concentration was observed in the waterless transportation group (18.78 g MSG/100 g), followed by the water-based transportation (15.33 g MSG/100 g) and fresh groups (12.08 g MSG/100 g). The contents of main taste-active compounds, especially umami amino acids, organic acids, Na+, Cl−, and 5′-nucleotides, were higher in the shrimp muscle of the waterless transportation group, which were more likely to be accepted and preferred. This research provided insights into improving shrimp muscle taste quality through the appropriate application of transportation strategies.

Combination of virtual screening, machine learning, molecular dynamics simulations and sensory evaluation to discover novel umami peptides from fermented Atlantic cod

The aim of this study was to explore the effect of fermentation with Lactobacillus helveticus Lh191404 on the umami characteristics of Atlantic cod and to elucidate the umami mechanism of the peptide. Post-fermentation significant increases in sweet amino acids (Threonine (Thr), Serine (Ser), Proline (Pro), Glycine (Gly), Alanine (Ala)) and umami amino acids (Aspartic acid (Asp), Glutamic acid (Glu)) enhanced the palatability and umami intensity of surimi. The calculated taste activity value showed Glu as the highest at 2.598, indicating that umami was the most prominent taste after the Atlantic cod fermentation. A new approach was constructed to batch screen high abundance umami peptides. Combined with Nano Liquid Chromatography Tandem Mass Spectrometry (nLC/MS-MS), virtual screening and machine learning identified four highly abundant umami peptides (WGDL, FDDLP, VAQWR, and YGESDL). Molecular docking and molecular dynamics simulations determined that they stably bind to the receptor proteins through hydrogen bonding and electrostatic interactions, with Asp108, Arg151, and Arg277 as the key active amino acids. Sensory evaluation and electronic tongue confirmed that the screened peptides were all umami peptides and the umami intensity was consistent with the simulation results. This study not only revealed that Lactobacillus helveticus Lh191404 enhanced the taste of fermented Atlantic cod by releasing high abundance umami peptides but also provided a novel approach for identifying umami peptides from fermented marine foods.

Effects of combined drying techniques and cellulase hydrolysis on the nutritional value and sensory properties of shiitake mushrooms (Lentinus edodes)

Dried shiitake mushrooms offer rich nutritional value and unique sensory properties, prompting further investigation. The effects of different drying techniques (hot air drying (HAD), infrared hot air drying (IRHAD), pulsed vacuum drying (PVD), vacuum freeze drying (VFD), and natural drying (ND)) combined with enzymatic hydrolysis on the release of flavor compounds and nutrients from shiitake mushrooms were explored. The combination of HAD with cellulase hydrolysis yielded notably high levels of umami amino acids (5.4723 ± 0.1501 mg/g) and 5′-nucleotides (4.0536 ± 0.0062 mg/g), and superior volatile flavors. Combined with cellulase hydrolysis, IRHAD achieved the highest level of total sugars (6.57 ± 0.34 mg/mL), VFD resulted in the greatest soluble protein content (153.21 ± 0.23 μg/mL), PVD yielded the highest total phenolics content (93.20 ± 0.41 μg GAE/mL), and ND produced the maximum reducing sugar content (5.79 ± 0.13 mg/mL). This study addresses crucial gap in the post-drying processing of shiitake mushrooms, offering valuable insights for further product development of shiitake mushrooms.