Revealing novel insights into the enhancement of quality in black tea processing through microbial intervention.

Black tea is highly favored by consumers worldwide, with enzymatic reactions being recognized as a pivotal factor influencing tea quality. The role of microorganisms in shaping the composition of black tea has emerged as a focus of research due to their involvement in enzyme catalysis and metabolic processes. In this study, full-length amplicon sequencing combined with qPCR more accurately reflected microbial profile, and Pantoea, Pseudomonas, Paucibacter, and Cladosporium were identified as the main microbial genera. Moreover, by comprehensively analyzing color, aroma, and taste components over time in black tea samples, correlations were established between the dominant genus and various quality factors. Notably, peroxidase activity levels, total soluble sugar content, and tea pigments concentration exhibited significant associations with the dominant genus. Consequently, this microbiological perspective facilitated the exploration of driving factors for improving black tea quality while establishing a theoretical foundation for quality control in industrial production.

The aroma transformation of Japanese sea bass (Lateolabrax japonicas) through endogenous enzyme incubation during the lag phase of attached microorganisms.

Endogenous enzymes play a crucial role in determining fish product aroma. However, the attached microorganisms can promote enzyme production, making it challenging to identify specific aromatic compounds resulting from endogenous enzymes. Thus, we investigated the aroma transformation of Japanese sea bass through enzymatic incubation by controlling attached microorganisms during the lag phase. Our results demonstrate that enzymatic incubation significantly enhances grassy and sweet notes while reducing fishy odors. These changes in aroma are associated with increased levels of 10 volatile compounds and decreased levels of 3 volatile compounds. Among them, previous studies have reported enzyme reaction pathways for octanal, 1-nonanal, vanillin, indole, linalool, geraniol, citral, and 6-methyl-5-hepten-2-one; however, the enzymatic reaction pathways for germacrene D, beta-caryophyllene, pristane, 1-tetradecene and trans-beta-ocimene remain unclear. These findings provide novel insights for further study to elucidate the impact of endogenous enzymes on fish product aromas.

Integrated characterization of arabica coffee husk tea using flavoromics, targeted screening, and in silico approaches.

This study aimed to identify the key volatile compounds in two types of processed arabica coffee husk tea, elucidate their olfactory characteristics, and investigate their antioxidant and anti-inflammatory activities. Sensory evaluation indicated differences between the two groups. A total of 64 and 99 compounds were identified in the C and FC groups, respectively, with 5 identified as key aroma compounds (ROAV≥1). Molecular simulations indicated that four common key aroma compounds were successfully docked with OR1A1 and OR5M3 receptors, forming stable complexes. Furthermore, 14 volatile compounds interacted with 140 targets associated with oxidation and inflammation, linking to 919 gene ontology (GO) terms and 135 kyoto encyclopedia of genes and genomes (KEGG) pathways. Molecular simulations revealed that these volatile components showed antioxidant and anti-inflammatory effects by interacting with core receptors through several forces, including van der Waals, Pi-alkyl, and Pi-cation interactions and hydrogen bonds.

Ethnobotany, phytochemistry, pharmacology and quality control of Peucedanum decursivum (Miq.) Maxim: A critical review.

ETHNOPHARMACOLOGICAL RELEVANCE: Dried roots of Peucedanum decursivum, a traditional Chinese medicine (TCM), has historically respiratory diseases such as cough, thick phlegm, headache, fever, and gynecological diseases, rheumatoid arthritis, and nasopharyngeal carcinoma. AIM OF THE STUDY: Made an endeavor to evaluate the research trajectory of P. decursivum, comprehensively discern its developmental status, and offer a guideline for future investigations. MATERIALS AND METHODS: A meticulous search of literatures and books from 1955 to 2024 via databases like PubMed, Web of Science and CNKI was conducted, including topics and keywords of " P. decursivum" "Angelica decursivum" and "Zihua Qianhu". RESULTS: P. decursivum and its prescriptions have traditionally been used for treating phlegm-heat cough, wind-heat cough, gastrointestinal diseases, pain relief and so on. It contains 234 identified compounds, encompassing coumarins, terpenes, volatile oils, phenolic acids, fatty acids and derivatives. It exhibits diverse pharmacological activities, including anti-asthmatic, anti-inflammatory, antioxidant effects, anti-hypertensive, anti-diabetic, anti-Alzheimer, and anti-cancer properties, primarily attributed to coumarins. Microscopic identification, HPLC fingerprinting, and bioinformatics identification are the primary methods currently used for the quality control. CONCLUSION: P. decursivum demonstrates anti-asthmatic, anti-inflammatory, and antioxidant effects, aligning with its traditional use. However, experimental validation of its efficacy against phlegm and viruses is needed. Additionally, analgesic effects mentioned in historical texts lack modern pharmacological studies. Numerous isolated compounds exhibit highly valuable medicinal properties. Future research can delve into exploring these substances further. Rigorous of heavy metal contamination, particularly Cd and Pb, is necessary. Simultaneously, investigating its pharmacokinetics and toxicity in humans is crucial for the safety.

The potential correlation between the succession of microflora and volatile flavor compounds during the production of Zhenba bacon.

Microbial composition plays an important role in the quality and flavor of bacon. The aims of this study were to detect bacterial community succession using high-throughput sequencing (HTS) and volatile flavor compound changes using gas chromatography-ion mobility spectrometry (GC-IMS) during the production of Zhenba bacon. The results showed that a total of 70 volatile compounds were detected. Among them, ketones, hydrocarbons, aldehydes, esters and alcohols were the main substances in the curing and smoking stages. In addition, the fungal abundance was greater than the bacterial abundance, and there was obvious succession of the microbial community with changes in fermentation time and processing technology. The main functional bacterial genera in the curing and smoking stages were Staphylococcus, Psychrobacter and Latilactobacillus, and the main fungal genera were Fusarium and Debaryomyces. Through correlation analysis, we found that pyrrole, 2-pentanol, methyl isobutyl ketone (MIBK) and ethyl acetate (EA) were significantly correlated with Staphylococcus, Psychrobacter, Pseudomonas and Myroides (p < 0.01), and it is speculated that they contribute significantly to flavor formation. The results of this study are helpful for understanding the microbial dynamics and characteristic volatile flavor compounds in Zhenba bacon, and provide new insights into the relationship between microorganisms and flavor through potential correlations.

Effect of different isolation sources of Lactococcus lactis subsp. lactis on volatile metabolites in fermented milk.

Lactococcus lactis subsp. lactis (L. lactis subsp. lactis) is a commonly used starter cultures in fermented dairy products, contributing distinct flavor and texture characteristics with high application value. However, the strains from different isolates have different contributions to milk fermentation. Therefore, this study aimed to investigate the influence of L. lactis subsp. lactis isolated from various sources on the volatile metabolites present in fermented milk. In this study, L. lactis subsp. lactis from different isolation sources (yogurt, koumiss and goat yogurt) was utilized as a starter culture for fermentation. The volatile metabolites of fermented milk were subsequently analyzed by headspace solid phase microextraction gas chromatography-mass spectrography (HS-SPME-GC-MS). The results indicated significant differences in the structure and abundance of volatile metabolites in fermented milk produced with different isolates (R2Y = 0.96, Q2 = 0.88). Notably, the strains isolated from goat yogurt appeared to enhance the accumulation of ketones (goat yogurt vs yogurt milk: 50 %; goat yogur vs koumiss: 27.3 %)and aldehydes (goat yogurt vs yogurt milk: 21.4 %; goat yogurt vs koumiss: 54.5 %) in fermented milk than strains isolated from koumiss and yogurt milk. It significantly promoted the production of 8 flavor substances (1 substance with OAV ≥ 1 and 6 substances with OAV > 0.1) and enhanced the biosynthesis of valine, leucine, and isoleucine. This study provides valuable insights for the application of Lactococcus lactis subsp. lactis isolated from different sources in fermented dairy production and screening of potential starter cultures.

Bamboo shoots improve the nutritional and sensory quality, and change flavor composition of chicken soup.

The effect of adding bamboo shoots to stewing on the quality and flavor of chicken soup has never been reported. Therefore, this study investigated the effects of 4 kinds of bamboo shoots on the edible quality, volatile and water-soluble flavor components of Chahua chicken soup. The results showed that adding bamboo shoots changed the sensory and nutritional quality of chicken soup. A total of 62 volatile flavor components were identified by HS-SPME-GC-MS, of which 12 were identified as characteristic volatile flavor components, and 9 were the main reasons for the flavor differences between bamboo shoot chicken soup with blank chicken soup. LC-MS found that after adding bamboo shoots, the differential water-soluble components in chicken soup significantly increased, and most of the increased components have been proven to have physiological functional activity. In conclusion, adding bamboo shoots improved the nutritional and sensory quality, and changed the flavor components of chicken soup.

A comparative study on flavor trapping techniques from the viewpoint of odorants of hot-pressed rapeseed oil.

Rapeseed oil, as one of the three major vegetable oils in the world, its matrix effect makes the decoding flavor a challenge. Solid-phase microextraction (SPME), SPME-Arrow, headspace stir bar sorptive extraction (HSSE), direct thermal desorption (DTD), and solvent-assisted flavor evaporation (SAFE) were compared based on the odorants in hot-pressed rapeseed oil. Besides, methodological validation for 31 aroma standards was conducted to compare reliability and robustness of these approaches. DTD showed the largest proportion of acids, while the other techniques extracted a majority of nitriles. The highest number of odorants was detected by SAFE (31), followed by HSSE (30), SPME-Arrow (30), SPME (24), and DTD (14). SPME-Arrow showed the best performance in linearity, recovery, and reproducibility followed by SPME, HSSE, DTD, and SAFE. Results reveal the advantages and limitations of diverse methodologies and provide valuable insights for the selection of extraction methods in an oil matrix and flavor decoding.

Metabolomics investigation on the volatile and non-volatile composition in enzymatic hydrolysates of Pacific oyster (Crassostrea gigas).

To investigate the differences of volatile and non-volatile metabolites between oyster enzymatic hydrolysates and boiling concentrates, molecular sensory analysis and untargeted metabolomics were employed. "Grassy," "fruity," "oily/fatty," "fishy," and "metallic" were identified as sensory attributes used to evaluate different processed oyster homogenates. Sixty-nine and 42 volatiles were identified by gas chromatography-ion mobility spectrometry and gas chromatography-mass spectrometry, respectively. Pentanal, 1-penten-3-ol, hexanal, (E)-2-pentenal, heptanal, (E)-2-hexenal, 4-octanone, (E)-4-heptenal, 3-octanone, octanal, nonanal, 1-octen-3-ol, benzaldehyde, (E)-2-nonenal, and (E, Z)-2,6-nonadienal were detected as the key odorants (OAV > 1) after enzymatic hydrolysis. Hexanal, (E)-4-heptenal, and (E)-2-pentenal were significantly associated with off-odor, and 177 differential metabolites were classified. Aspartate, glutamine, alanine, and arginine were the key precursors affecting the flavor profile. Linking sensory descriptors to volatile and nonvolatile components of different processed oyster homogenates will provide information for the process and quality improvement of oyster products.

Comparison of potent odorants in raw and cooked mildly salted large yellow croaker using odor-active value calculation and omission test: Understanding the role of cooking method.

Cooking improves food aroma, but few studies have explored how cooking affects food aromas. Here, aroma changes in mildly salted large yellow croaker (Larimichthys crocea, MSLYC) after steaming, baking, frying, and deep frying was investigated. The raw fish was dominated by fishy notes but after cooking, the aroma became dominated by fatty notes. Nine volatiles, including hexanal, nonanal, (E, Z)-2, 6-nonadienal, (E, E)-2, 4-decadienal, 1-octen-3-ol, linalool, ethyl hexanoate, acetic acid and anethole, were identified as key odor-active compounds using GC-MS, OAV, and omission tests analyses. Changes in the concentrations of key odor-active compounds were mainly due to evaporation, oxidation of linolenic acids, and thermal catalyzed reactions. Interestingly, anethole was the key odor-active compound, providing new insight into the underlying reactions of cooked fish aroma.

Hydrophobic bonds-dominated key off-odors/silver carp myofibrillar protein interactions, and their binding characteristics at cold storage and oral temperatures.

This study revealed the interaction mechanism between silver carp myofibrillar protein (MP) and key off-odors by combining fluorescence spectroscopy with molecular dynamics (MD) simulation. Spectroscopic results exhibited a dynamic quenching mechanism between MP and off-odors. Thermodynamic analysis indicated that the MP/off-odors interaction was spontaneous (ΔG° < 0) and dominated by hydrophobic interactions (ΔH° > 0, ΔS° > 0). Meanwhile, the binding affinity was in the order of nonanal (n = 1.38) > hexanal (n = 0.89) > 1-octen-3-ol (n = 0.65), which was further verified by the MD results. Among off-odors, nonanal had the highest binding energy with myosin (8105.66 kJ/mol) and formed more hydrophobic binding sites to Trp residues in myosin head (e.g., Trp820 and Trp822), thereby changing myosin conformations via both physical and chemical interactions. Additionally, higher binding energies of myosin/off-odors were observed at oral temperature (37 °C) than at cold storage temperature (4 °C), implying that less off-odors were released at 37 °C.

Effects of temporary rearing with organic selenium on the muscle flavor and texture properties of largemouth bass (Micropterus salmonides).

In this study, the influences of organic selenium (Se, 0.002 mg/L) on the muscle flavor and texture properties of Micropterus salmonides under fasting temporary rearing (8 weeks) was investigated. Electronic nose and headspace solid-phase microextraction-gas chromatography-mass spectrometry analysis suggested that organic Se regulated the types and contents of volatile compounds, especially aldehydes and ketones, which were increased in the early temporary rearing but decreased in the late stage. Organic Se significantly increased the content of 5'-inosine monophosphate by approximately 15 % (p < 0.05), and decreased the content of hypoxanthine and hypoxanthine ribonucleoside by more than 20 % (p < 0.05). After the 8th temporary rearing week, muscle hardness and springiness increased by at least 10 % (p < 0.01), resilience and gumminess improved by at least 18 % (p < 0.05) and 5.9 % (p < 0.05), respectively. In conclusion, organic Se ameliorates the flesh quality of M. salmonides during long-term temporary rearing.

Characterization of key aroma compounds in low-salt fermented sour fish by gas chromatography-mass spectrometry, odor activity values, aroma recombination and omission experiments.

In this study, key aroma compounds of low-salt fermented sour fish were characterized using headspace solid-phase micro extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS), odor activity values (OAV) and aroma recombination and omission experiments. Eighty-eight volatile compounds, including esters, aldehydes, alcohols, acids, furans and pyrazines, were identified by HS-SPME-GC-MS. Eighteen aroma-active compounds were quantified by employing calculation of OAV greater than 1. A recombination aroma model prepared using aroma-active compounds based on the odorless fish matrix sensorially matched the aroma of fermented sour fish with a score of 4.5 out of 5. The omission experiment showed that 7 out of 18 compounds had a significant contribution to the overall aroma (P < 0.05). The key aroma compounds of fermented sour fish were concluded to be ethyl acetate (OAV = 189), ethyl hexanoate (OAV = 66), isoamyl acetate (OAV = 424), ethyl butyrate (OAV = 26), hexanal (OAV = 49), 1-hexadecanal (OAV = 14) and 2-pentylfuran (OAV = 13).

Characterization of key aroma compounds and relationship between aroma compounds and sensory attributes in different aroma types of Fu brick tea.

Aroma is one of the most important sensory properties of tea. Floral-fungal aroma type, ripe-fungal aroma type and fresh-fungal aroma type were the main aroma types of Fu brick tea by QDA. A total of 112 volatile compounds were identified and quantified in tea samples by HS-SPME/GC-MS analysis. Ten voaltiles in floral-fungal aroma type, eleven voaltiles in ripe-fungal aroma type, and eighteen voaltiles in fresh-fungal aroma type were identified as key aroma compounds for the aroma characteristics formation in three aroma types of Fu brick tea. In addition, PLS analysis revealed that 3,4-dehydro-ß-ionone, dihydro-ß-ionone, (+)-carotol and linalool oxide Ⅱ were the key contributors to the 'floral and fruity' attribute, α-terpineol contributed to 'woody' and 'stale' attributes, and thirteen aroma compounds related to 'green' attribute. Taken together, these findings will provide new insights into the formation mechanism of different aroma characteristics in Fu brick tea.

Applicability of pea ingredients in baked products: Links between formulation, reactivity potential and physicochemical properties.

This study aimed to evaluate the applicability of purified pea ingredients (starch and protein isolate) by assessing their potential to form volatile compounds during the different steps of sponge cake development compared to pea flour and wheat flour. While pea flour was highly susceptible to lipid oxidation during batter beating, the combination of purified pea starch and pea protein yielded significantly fewer oxidation markers with known green-beany off-odors. This was due more to the inactivation of lipoxygenase during flour fractionation than to differences in batter structure. However, fractionated ingredients were highly prone to participating in the Maillard reaction and caramelization during baking, leading to a more complex mixture of pyrazines, Strecker aldehydes and furanic compounds with potential malty and roasted notes compared to cakes based on pea flour or wheat flour. These findings confirm that using purified pea fractions can create high-quality products with an attractive composition.

Effect of ultrasound on functional properties, flavor characteristics, and storage stability of soybean milk.

The effects of different ultrasound treatments (20 kHz at 400 W for 0 to 9 min) on the functional properties, flavor characteristics, and storage stability of soybean milk at 4 °C were investigated. Results indicated that non-sonicated soymilk had the maximum particle size D4, 3 of 2.47 ± 0.47 µm, while 9 min high intensity ultrasound (HIU) decreased D4, 3 to 0.44 ± 0.01 µm. 9 min of HIU decreased the total number of microorganisms in soymilk from 4.51 to 3.95 Log (CFU/mL). Moreover, 9 min HIU increased the absolute value of ζ-potential from 36.43 to 34.13 mV. Turbiscan test showed that 9 min HIU decreased the instability index of soymilk from 0.78 to 0.65. Furthermore, sensory analysis, electronic nose, electronic tongue, and gas chromatography-mass spectrometry showed that 7 min HIU decreased the content of aldehydes, furans, ketones, and alcohols by 52.09%, 75.01%, 56.79%, and 57.27%, respectively.

Reduction of aldehydes with green odor in soy products during fermentation with Lycoperdon pyriforme and analysis of their degradation products.

Soy products are rejected by Western consumers because of their green and beany off-aroma. The off-aroma profiles of typical soy products (soy drink and soy protein isolate) were analyzed and forty-five regions imparting green and beany odor impressions were perceived after application of direct immersion-stir bar sorptive extraction coupled with gas chromatography-mass spectrometry-olfactometry. After a fermentation of 28 h with Lycoperdon pyriforme the intensity of the off-aroma was reduced. Accordingly, thirteen and fourteen of the thirty-five quantified compounds were significantly decreased after fermentation of soy drink and soy protein isolate, respectively. The major off-aroma contributors, aldehydes, were reduced during fermentation and their degradation products were analyzed. The following bio-pathways were suggested (i) saturated aldehydes were reduced to the corresponding alcohols with increased odor threshold, leading to less intense sensorial perception, and (ii) di-unsaturated aldehydes did not form any odor-active substance in the volatile spectrum. Both of the phenomena explained the decreased sensorial perception of the off-aroma.

The identification of biotransformation pathways for removing fishy malodor from Bangia fusco-purpurea using fermentation with Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae is effective in reducing the fishy malodor of sea products. However, the biotransformation pathways are still unclear. The seaweed B. fusco-purpurea was taken as an example to investigate the chemical transformation pathways for the deodorization process with S. cerevisiae fermentation. Sensory evaluation, GC-MS, GC-MS-O and odor activity value (OAV) analyses showed the fishy odorants were 1-octen-3-ol, (E)-2-nonenal, 2,4-decadienal, 2-pentylfuran, 2-octen-1-ol and nonanal. The removal of fishy malodor was related to the reactions of reduction, dehydrogenation, deformylation-oxygenation and ester syntheses via catalysis of aldehyde dehydrogenase, alcohol dehydrogenases, epoxide hydrolase, aldehyde deformylating-oxygenase, enone reductase, oxidases, dehydrogenases, aldo-keto reductases, ester synthase and acyltransferase. Interestingly, for the first time, it was found that 3,5-octadien-2-one transformed to 6-octen-2-one; and 2-pentylfuran transformed to o-cymene and hexyl acetate. Our findings enrich the knowledge for the removal of fishy malodor from sea products such as seaweeds.

Non-volatile and volatile metabolic profiling of tomato juice processed by high-hydrostatic-pressure and high-temperature short-time.

High hydrostatic pressure (HHP) processing has become a commercial success in fruit and vegetable processing. Herein, the effects of HHP and high-temperature short-time (HTST) processing on metabolic profiling in tomato juice was evaluated by UPLC-MS/MS, HPLC, and GC-MS; a total of 425 metabolites, 14 carotenoids, and 56 volatile compounds were identified in tomato juice. HHP processing affects the composition of the juice less than HTST processing, considering 4 and 33 differential metabolites discriminated after HHP and HTST processing, respectively. The total lycopene and carotenoid contents in tomato juice increased after HHP processing, while the ß-carotene and lycopene contents decreased after HTST processing. Further, more volatile compounds and higher contents of aldehydes that contribute to green aroma and lower contents of alcohols were observed after HHP and HTST processing, respectively. These findings provide a comprehensive understanding of the advantages of HHP processing on metabolite profiles in tomato juice.

Caferana seeds (Bunchosia glandulifera) as a new source of nutrients: Evaluation of the proximal composition, solvent extraction, bioactive compounds, and δ-lactam isolation.

The proximal composition, amino acid, carbohydrate, and volatile profiles of caferana (Bunchosia glandulifera) seeds flour were here assessed. Seeds were also subjected to the following extraction processes: one with pressurized ethanol (PLE) and two with ethanol + supercritical CO2 mixture at different temperatures and pressures (SC1 and SC2). Extracts were characterized in terms of caffeine, total phenolic, and δ-lactam. The characterization of caferana seed and its extracts is unprecedented in terms of carbohydrate and volatiles profiles, besides the δ-lactam identification/isolation. SC2 extract exhibited a higher caffeine (9.3 mg/g) and δ-lactam (29.4 mg/g) content, whereas the PLE extract contained a higher total phenolic amount (3.0 mgGAE/g). Caferana is regionally associated to protective effects on mental health. Its byproduct (seed) revealed to be a promising source of bioactive compounds, and a potential raw material of nutritive extracts and flours that can be incorporated into pharmaceutical, nutraceutical, cosmetic, and food products.