ABSTRACT
Aroma is a crucial indicator of hop quality. This study analyzed the differences in aroma compound composition among six hop varieties from three regions: North America, Europe, and Asia. Descriptive analysis and sensomic approaches including gas chromatography-olfactometry/aroma extract dilution analysis, odour activity value calculation and aroma recombination were used for the detailed characterization and comparative analysis of hop aroma. A total of 55 aroma-active compounds were identified. Among them, linalool, geraniol, ß-myrcene, 2-undecanone, and methyl decanoate contributed significantly to hop aroma. Orthogonal partial least squares discriminant analysis revealed that, except for the SAAZ and XinYuan hops with some similarities in their aroma composition, the remaining hops exhibited unique aroma characteristics. A total of 16 compounds, including methyl 5-methylhexanoate and (E)-ß-farnesene, were identified as differentiating aroma compounds in the six hop samples. This study enriches the knowledge on hop flavour with different origins and provides valuable insights into its application.
ABSTRACT
Chinese wild rice (CWR) is a nutritious and healthy whole grain, worth developing. To develop and use its value, a new type of huangjiu was brewed with CWR, and the flavour characteristics, sensory quality, functional and bioactive components were evaluated. CWR (67 flavour substances) and glutinous rice (GR)-CWR huangjiu (62 flavour substances) had a better flavour than GR huangjiu (54 flavour substances), and the overall style of GR-CWR huangjiu was more skewed towards GR. The fruity, honey, caramel-like, herb and smoky aroma attributes of CWR huangjiu were higher than those of GR huangjiu (P < 0.05), while only the alcoholic was weaker (P < 0.05) due to the lower alcohol content. The huangjiu brewed using CWR had a better taste than that brewed using only GR. Furthermore, CWR huangjiu had the highest content of total dietary fiber (732.0 ± 15.2 mg/100 g), followed by GR-CWR (307.0 ± 8.5 mg/100 g), and GR (127.0 ± 2.3 mg/100 g). CWR huangjiu also had the highest total phenolic compounds (3.32 ± 0.05 mg/100 g/%vol) and total saponins (2.46 ± 0.03 mg/100 g/%vol) contents, followed by GR-CWR and GR. This study provides guidance for exploring further possibilities for CWR in the future.
Subject(s)
Fermentation , Flavoring Agents , Odorants , Oryza , Taste , Humans , Odorants/analysis , Oryza/chemistry , Oryza/metabolism , Flavoring Agents/chemistry , Flavoring Agents/analysis , Adult , Female , Male , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/analysis , Young Adult , Poaceae/chemistry , Poaceae/metabolism , East Asian PeopleABSTRACT
Among the eight types of aroma and flavour characteristics of Chinese flue-cured tobacco (FCT), tobacco grown in Shandong is classified as having a honey-sweet and burnt aroma. To elucidate the key chemical components that determine the characteristics of the honey-sweet and burnt aroma styles of Shandong FCT, we qualitatively and quantitatively evaluated the smoke flavour quality and five categories of flavour-related chemical components (routine components, water-soluble sugars, free amino acids, Amadori compounds and key aroma-active compounds) in Shandong middle FCT leaves using sensory analysis and modern instrumental analysis techniques. The association between the chemical components and sensory quality was analysed. Our results showed that the total sugars, reducing sugars (fructose, glucose, and psicose), total sugar-nicotine ratio, proline-total amino acid ratio, sulphur-containing amino acid-total amino acid ratio and fructosyl-proline (Fru-Pro) were high in premium FCT leaves. The aroma-active compounds associated with the honey-sweet burnt flavour style of the Shandong Middle FCT included sweet-scented 2,3-pentanedione, 2,3-butanedione, butyrolactone, 2-furanmethanol, roasted-like 2-pentylfura, and green-like 1-penten-3-one. Partial least squares regression (PLSR) analysis revealed that 29 aroma precursors were positively correlated with the sensory quality characteristics of Shandong FCT. The results of our study can provide guidance for the targeted improvement and precise regulation of the flavour-style characteristics of Shandong FCT.
ABSTRACT
The flavor of cigar tobacco leaf determines the quality of finished cigar tobacco, and the enhancement of flavor generally relies on microbial fermentation. In this paper, the correlation between the dominant microorganisms and the main flavor substances of cigar tobacco leaves during fermentation and the correlation between the two were investigated to reveal the correlation between microorganisms and flavor and the metabolic pathways of microorganisms affecting the flavor substances. During the fermentation process, the main flavors of cigar tobacco leaves were sweet, light and grassy, with hexanal, 2,6-dimethylpyridine, nonanal, phenylacetaldehyde, naphthalene, and methyl benzoate as the main constituents, and the key microorganisms Haloferax mediterranei, Haloterrigena limicola, Candidatus Thorarchaeota archaeon SMTZ-45, the genera Methyloversatilis, Sphingomonas, Thauera, Pseudomonas, Penicillium, and Aspergillus. Correlation analysis revealed that fungi were negatively correlated with the main aroma and inhibited the main flavor substances, while bacteria were positively correlated with Benzoic acid, methyl ester in the main flavor substances, which was conducive to the accumulation of green aroma. Functional analysis revealed that the dominant bacterial population was producing aroma by metabolizing glycoside hydrolases and glycosyltransferases, performing amino acid metabolism, carbohydrate metabolism and film transport metabolism. The present study showed that the bacterial and fungal dominant microorganisms during the fermentation of cigar tobacco were influencing the production and degradation of the main flavor substances through the enzyme metabolism by the occurrence of the Merad reaction.
ABSTRACT
Background: Because lung cancer is the main cause of cancer deaths and lung adenocarcinoma (LUAD) accounts for more than 40% of all lung malignancies, it is essential to develop clinically useful biomarkers for the disease. The aim of this investigation is to assess the potential application of tubulin alpha-1b (TUBA1B) as a biomarker for diagnosing and monitoring the outcome of LUAD. Methods: The clinical data of the LUAD patients was retrospectively analyzed. Immunohistochemistry (IHC) analysis of a tissue microarray containing 90 LUAD cases was implemented to examine the expression of TUBA1B. The protein and mRNA levels of TUBA1B in serum were detected by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR (qRT-PCR) analysis respectively. UALCAN was employed to confirm the expression levels and survival probability of TUBA1B in LUAD patients. Results: Compared to adjacent non-cancerous tissues in the microarray, the expression of TUBA1B in LUAD tissues was much higher. The expression of TUBA1B in LUAD was statistically correlated with lymph node status (P = .031). Moreover, patients with higher TUBA1B expression had shorter overall survival (P < .0001). Furthermore, cox multi-factor analysis also suggested that TUBA1B may be an independent predictor for LUAD prognosis (P = .030). The results of TCGA data analysis by UALCAN were consistent with the microarray results, except for that TUBA1B was also significantly correlated with clinical tumor stages. Protein levels of TUBA1B in serum were obviously elevated in LUAD patients than control (P < .0001), and the area under the ROC curve was 0.99. TUBA1B also showed better sensitivity of 92.9% for LUAD than common clinical biomarkers. Conclusion: TUBA1B may be a non-invasive prognostic and diagnostic biomarker for LUAD patients.
Subject(s)
Adenocarcinoma of Lung , Lung Neoplasms , Humans , Tubulin/genetics , Retrospective Studies , Adenocarcinoma of Lung/genetics , Prognosis , Lung Neoplasms/diagnosis , Lung Neoplasms/genetics , BiomarkersABSTRACT
OBJECTIVE: To investigate the possible causes of abnormal hemoglobin electrophoresis results. METHODS: The hemoglobin electrophoresis results of 5 696 patients in the First Affiliated Hospital of Chengdu Medical College from September 2018 to July 2021 were collected, and the abnormal results and clinical significance were analyzed. RESULTS: The results of 486 patients (accounting for 8.53%) were abnormal, of which 300 cases had increased HbA2, 135 cases had decreased HbA2, 44 cases had increased F alone, and 7 cases had abnormal hemoglobin bands. Among the 486 patients, 246 patients were thalassemia gene positive (the positive rate was 50.62%), including 29 cases of α thalassemia, 208 cases of ß thalassemia and 9 cases of αß thalassemia. Among the patients with elevated HbA2, 68.67% were detected ß thalassemia, 3.00% αß thalassemia, 9.33% were suspected to be caused by macrocytosis, 6.33% by thyroid dysfunction, and 12.67% by uncertainty of the method. Among the patients with reduced HbA2, 21.48% were detected α thalassemia, 60.00% iron deficiency anemia, 8.15% were suspected to be caused by thyroid dysfunction, and 10.37% by uncertainty of the method. Among the patients with elevated F alone, the results of thalassemia gene detection were negative, 40.91% of them were suspected to be caused by macrocytosis, 27.27% by hereditary persistence of fetal hemoglobin, 29.55% by special physiological condition of pregnant women, and 2.27% by hyperthyroidism. Abnormal hemoglobin bands were detected in 7 patients, including 4 cases of hemoglobin D, 2 cases of hemoglobin E, and 1 case of hemoglobin J. CONCLUSION: Thalassemia, iron deficiency anemia, macrocytosis such as megaloblastic anemia and non-severe aplastic anemia, thyroid dysfunction, hereditary persistence of fetal hemoglobin, abnormal hemoglobin diseases, the uncertainty of the method are all important causes of abnormal hemoglobin electrophoresis results. In clinical work, the patient's indicators should be comprehensively analyzed to determine the possible cause.
Subject(s)
Anemia, Iron-Deficiency , Hemoglobins, Abnormal , alpha-Thalassemia , beta-Thalassemia , Humans , Female , Pregnancy , beta-Thalassemia/genetics , Fetal Hemoglobin/analysis , Blood Protein Electrophoresis , Hemoglobin A2/analysis , Hemoglobins, Abnormal/analysisABSTRACT
OBJECTIVE: To investigate gene mutation types of thalassemia in the population of this area and the relationship between hematological phenotype and age in ß-thalassemia. METHODS: 1 351 suspected cases of thalassemia were detected in the First Affiliated Hospital of Chengdu Medical College from June 2017 to June 2021. PCR-reverse dot blot hybridization(PCR-RDB) technique was used to detect the common α and ß thalassemia gene types, then the data of MCV, MCH, MCHC and Hb of confirmed cases were collected. The heterozygotes of ß-thalassemia were divided into 0-18 year group, 19-50 year group and >50 year group according to age, and the differences of hematological phenotypes among different groups were compared. RESULTS: Among the detected 1 351 samplesï¼ 523(38.71%) cases were diagnosed as thalassemia, 13 genotypes were detected in 260 cases (19.25%) with α-thalassemia; and 12 genotypes were detected in 252 cases (18.65%) with ß-thalassemia; 9 genotypes were detected in 11 cases with αß thalassemia. It was found that MCV and MCH were increased significantly in 0-18 year group, 19-50 year group and >50 year group, MCHC was highest in 0-18 year group, and Hb was the lowest in the >50 year group, and the difference was statistically significantï¼P<0.05ï¼. CONCLUSION: In this area, --SEA/αα was the major genotype of α-thalassemia, and CD41-42 /N and IVS-II-654/N were the major genotypes of ß-thalassemia. Morever, MCV and MCH were the lowest in the 0-18 year old group and the highest in the >50 years old group in heterozygotes of ß-thalassemia. The influence of age on hematological parameters in the primary screening of thalassemia provides a certain reference value in clinical diagnosis and treatment.
Subject(s)
alpha-Thalassemia , beta-Thalassemia , China/epidemiology , Genotype , Heterozygote , Humans , Mutation , Phenotype , alpha-Thalassemia/epidemiology , alpha-Thalassemia/genetics , beta-Thalassemia/epidemiology , beta-Thalassemia/geneticsABSTRACT
Mint is a widely used aromatic plant, and the aroma varies among different species. The aroma of five mint species, Mentha citrata L. (MC), Mentha piperita L. (MPI), Mentha spicata L. (MSP), Mentha persicaria L. (MPE), and Mentha suaveolens L. (MSU), were comparatively studied on the sensorial and molecular level. Quantitative descriptive analysis revealed that MC presented a pronounced lemon-like note, MSU is dominated by citrus and floral aromas, MPI has a prominent minty flavor, MSP and MPE have a similar scent, both of which are flavored with a spearmint-like note. Forty-one odorants with odor activity values (OAVs) ≥1 were characterized. Principal component analysis and orthogonal partial least squares discrimination analysis based on OAVs indicated that α-citral, menthofuran, isomenthone, menthol, carvone, and linalool were potential odor-active markers for five mint species discrimination. This study herein will provide guidance for mint resources utilization and also aid mint breeding with better flavor.
Subject(s)
Mentha spicata , Mentha , Volatile Organic Compounds , Flavoring Agents , Odorants/analysis , Plant BreedingABSTRACT
Proso millet (Panicum miliaceum L.) is a minor cereal crop that has been considered as health-promoting food. Little information is available however, about the metabolic basis of nutritional values of proso millet. In this study, using a UHPLC-QqQ-MS/MS-based metabolomics approach, we compared the metabolomes of whole grains from four proso millet varieties with different bran color, namely White, Black, Gray and Red. In total, 672 metabolites were identified, among which 121, 116 and 148 metabolites showed differential accumulation in the three comparison groups (White vs. Black/Gray/Red). The results demonstrated the main pathways that were differentially activated included: tryptophan metabolism, flavonoid, isoflavonoid, flavone, and flavonol biosynthesis. Considerable difference between varieties was observed in accumulation of phenolic acids and flavonoids, which might lead to difference in antioxidant activities. The results of this study provide useful information for further investigation of proso millet food chemistry and for sufficient utilization of this special crop.
ABSTRACT
The major aroma-active compounds in clear red raspberry juice were identified by molecular sensory science approaches. Thirty-one aroma-active compounds were identified using detection frequency analysis and aroma extract dilution analysis. Among them, 18 volatiles with aroma activity in red raspberry were identified for the first time, while 14 volatiles with odor activity values (OAVs) ≥ 1 were confirmed as the major aroma-active compounds. Three C6 aldehydes showed the highest detection frequencies of 8, and ß-ionone exhibited the highest OAV of 9507 and flavor dilution factor of 512, which indicated that the floral and grassy note could be dominant in overall aroma. Quantitative descriptive analysis suggested that the grassy, floral, woody, and caramel-like notes can be simulated using aroma recombination model 1. Electronic nose analysis also demonstrated that model 1 had closer similarity to the original juice than others. The combination strategy used here would help improve the knowledge of red raspberry aroma.
Subject(s)
Flavoring Agents/analysis , Fruit and Vegetable Juices/analysis , Rubus/chemistry , Volatile Organic Compounds/analysis , Discriminant Analysis , Electronic Nose , Flavoring Agents/isolation & purification , Gas Chromatography-Mass Spectrometry , Norisoprenoids/isolation & purification , Principal Component Analysis , Rubus/metabolism , Solid Phase Microextraction , Volatile Organic Compounds/isolation & purificationABSTRACT
Sweet osmanthus (Osmanthus fragrans Lour.) (OF) is one of the ten most famous flowers in China for its unique and delicate fragrance. A combined solid-phase microextraction and solvent-assisted flavor evaporation method was used to accurately capture the overall aromatic profile and characterize the predominant odorants of fresh osmanthus with the help of gas chromatography (GC)-olfactometry and comprehensive two-dimensional GC-quadrupole time-of-flight mass spectrometry (GC × GC-QTOF-MS). Twenty-six volatiles were identified for the first time in OF. A total of 23 potent odorants, dominated by monoterpene oxides and C6 aliphatic aldehydes, were identified. The efficacy of pectinase, ß-glucosidase, and their combination on the aroma enhancement of OF was evaluated by quantitation of the target aroma components using GC-triple quadrupole-MS. The total concentration of key aroma components increased in all three enzyme treatment groups, and the increase was more significant in two ß-glucosidase-treated groups. Changes in odor activity values and odor spectrum values of key odorants indicated that the pectinase-treated sample had more prominent floral, green, and potato-like scents. In contrast, the ß-glucosidase-treated sample had more dominant floral, woody, almond-like, and fruity notes but less green odor, which was confirmed by sensory evaluation. ß-Glucosidase and pectinase complement one another very well, and together, promote a remarkable aroma enhancement in OF.
Subject(s)
Flavoring Agents/chemistry , Odorants/analysis , Oleaceae/chemistry , Polygalacturonase/chemistry , beta-Glucosidase/chemistry , Biocatalysis , China , Flavoring Agents/isolation & purification , Flowers/chemistry , Food Handling , Gas Chromatography-Mass Spectrometry , Solid Phase Microextraction , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/isolation & purificationABSTRACT
Enterobacter cloacae complex (ECC), one of the most common opportunistic pathogens causing multiple infections in human, is resistant to ß-lactam antibiotics mainly due to its highly expressed chromosomal AmpC ß-lactamase. It seems that regulation of chromosomal AmpC ß-lactamase is associated with peptidoglycan recycling. However, underlying mechanisms are still poorly understood. In this study, we confirmed that NagZ, a glycoside hydrolase participating in peptidoglycan recycling in Gram-negative bacteria, plays a crucial role in developing resistance of E. cloacae (EC) to ß-lactam antibiotics by promoting expression of chromosomal AmpC ß-lactamase. Our data shows that NagZ was significantly up-regulated in resistant EC (resistant to at least one type of the third or fourth generation cephalosporins) compared to susceptible EC (susceptible to all types of the third and fourth generation cephalosporins). Similarly, the expression and ß-lactamase activity of ampC were markedly enhanced in resistant EC. Moreover, ectopic expression of nagZ enhanced ampC expression and resistance to ß-lactam antibiotics in susceptible EC. To further understand functions of NagZ in ß-lactam resistance, nagZ-knockout EC model (ΔnagZ EC) was constructed by homologous recombination. Conversely, ampC mRNA and protein levels were down-regulated, and resistance to ß-lactam antibiotics was attenuated in ΔnagZ EC, while specific complementation of nagZ was able to rescue ampC expression and resistance in ΔnagZ EC. More interestingly, NagZ and its hydrolyzates 1,6-anhydromuropeptides (anhMurNAc) could induce the expression of other target genes of AmpR (a global transcriptional factor), which suggested that the promotion of AmpC by NagZ is mediated AmpR activated by anhMurNAc in EC. In conclusion, these findings provide new elements for a better understanding of resistance in EC, which is crucial for the identification of novel potential drug targets.
ABSTRACT
High-throughput sequencing and gas chromatography-mass spectrometry (GC-MS) were used to investigate changes in bacterial and fungal communities and volatile flavor compounds during a 32-day fermentation process of red pepper (Capsicum annuum L.). Key odorants were identified by olfactometry combined with GC-MS. Sixteen volatile compounds differed significantly after fermentation, including seven odorants. After fermentation, 1-butanol, 3-methyl-, acetate, phenol, 4-ethyl-2-methoxy-, octanoic acid, ethyl ester, styrene and 2-methoxy-4-vinylphenol were the key odorants, producing a flavor described as peppery, fruity, sour, and spicy. The correlation between microorganisms and odorants in the fermentation was studied and 18 odorants significantly correlated with the core microbial communities in the fermented samples. For further analysis, strains of seven genera were isolated and correlation analysis by O2PLS indicated that Aspergillus, Bacillus, Brachybacterium, Microbacterium and Staphylococcus were highly correlated with the flavor formation. These findings would help to understand the fermentation mechanism of fermented red pepper flavor formation.
Subject(s)
Capsicum/microbiology , Fermented Foods , Microbiota , Odorants/analysis , Acids/analysis , Acids/chemistry , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , Bacteria/metabolism , Biodiversity , Fermentation , Fermented Foods/analysis , Fermented Foods/microbiology , Fungi/classification , Fungi/genetics , Fungi/isolation & purification , Fungi/metabolism , Hydrogen-Ion Concentration , Taste , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/metabolismABSTRACT
Gas chromatography-olfactometry (GC-O) coupled with GC-mass spectrometry (GC-MS) and aroma recombination-omission experiments led to the identification of the key aroma compounds responsible for the different flavors of raw and roasted peas. The results demonstrated that a total of 30 odorants were identified in raw and roasted peas. Nine and twenty compounds were identified as important odorants in raw and roasted peas with odor activity values (OAVs) greater than 1, respectively. Aroma recombination-omission experiments demonstrated that six aroma compounds significantly contributed to the characteristic aroma of peas (p < 0.05). Among these, 3-methylbutanoic acid (OAV = 382) and hexanal (OAV = 280) significantly contributed to the aroma of peas. Fifteen aroma compounds significantly contributed to the characteristic aroma of roasted peas (p < 0.05). Among these, pyrazines and pyranones showed important contribution to the aroma of roasted peas. Roasting increased the variety of key aroma compounds significantly and contributed a nutty flavor to peas. The comprehensive aroma characterization of peas and determination of the effect of roasting on key aroma compound alteration will be helpful for new pea products' flavor quality control.
Subject(s)
Flavoring Agents/chemistry , Volatile Organic Compounds/chemistry , Adult , Cooking , Female , Fruit/chemistry , Gas Chromatography-Mass Spectrometry , Humans , Male , Odorants/analysis , Olfactometry , Pisum sativum/chemistry , Smell , Young AdultABSTRACT
BACKGROUND: Detection of ceftazidime/avibactam (CAZ/AVI) antibacterial activity is absolutely vital with the rapid growth of carbapenem resistant Enterobacteriaceae (CRE). But now, there is no available automated antimicrobial susceptibility testing card for CAZ/AVI, so Kirby-Bauer has become an economical and practical method for detecting CAZ/AVI antibacterial activity against Enterobacteriaceae. RESULT: In this study, antimicrobial susceptibility testing of CAZ/AVI against 386 Enterobacteriaceae (188 Klebsiella pneumoniae, 122 Escherichia coli, 76 Enterobacter cloacae) isolated from clinical patients was performed by broth microdilution. Of the 386 strains, 54 extended spectrum ß lactamases negative (ESBL(-)), 104 extended spectrum ß lactamases positive (ESBL(+)), 228 CRE. 287 isolates were susceptible to CAZ/AVI and 99 isolates were resistant to CAZ/AVI. At the same time, to obtain optimal content avibactam (AVI) disk containing ceftazidime (30 µg), inhibition zone diameter of four kinds of ceftazidime (30 µg) disk containing different AVI content (0 µg, 10 µg, 25 µg, 50 µg) were tested by Kirby-Bauer method. The microdilution broth method interpretation was used as the standard to estimate susceptible or resistance and then coherence analysis was carried out between Kirby-Bauer and broth microdilution. The result shows the inhibition zone diameter of 30 µg/50 µg disk, susceptible isolates: 20.5 mm-31.5 mm, resistance isolates: 8.25 mm-21.5 mm. The inhibition zone diameter of 30 µg/25 µg disk, susceptible isolates: 19.7 mm-31.3 mm, resistance isolates: 6.5 mm-19.2 mm. The inhibition zone diameter of 30 µg/10 µg disk, susceptible isolates: 19.5 mm-31 mm, resistance isolates: 6.5 mm-11 mm. The inhibition zone diameter of ceftazidime (30 µg), susceptible isolates: 6.5 mm-27.5 mm, resistance isolates 6.5 mm. CONCLUSION: Our results show that 30 µg/50 µg, 30 µg/25 µg, 30 µg/10 µg CAZ/AVI disk have significant statistical differences to determinate CAZ/AVI antibacterial activity, but for 30 µg/50 µg disk, there has a cross section between susceptible isolates (minimum 20.5 mm) and resistance isolates (maximum 21.5 mm). For 30 µg/25 µg disk, it is hard to distinguish the difference between susceptible isolates (minimum 19.7 mm) and resistance isolates (maximum 19.2 mm), so 30 µg/10 µg CAZ/AVI disk is more conducive to determinate antibacterial activity.
Subject(s)
Azabicyclo Compounds/pharmacology , Ceftazidime/pharmacology , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/drug effects , China , Disk Diffusion Antimicrobial Tests , Dose-Response Relationship, Drug , Drug Combinations , Drug Resistance, Bacterial , Enterobacteriaceae/classification , HumansABSTRACT
Infusions prepared from raw pu-erh tea (RAPT) and ripened pu-erh tea (RIPT) showed remarkable aroma differences. Predominant odorants in RAPT and RIPT infusions were identified and compared by the combined use of gas chromatography-olfactometry, aroma extract dilution analysis, odor activity values (OAVs), and multivariate analysis. A total of 35 and 19 odorants (OAV > 1) were detected in RIPT and RAPT, respectively. Odorants in RAPT and RIPT are significantly different in both odor properties and aroma compound intensities. Overall, RAPT contained a complex variety of chemical classes with diverse odors and moderate odor intensities, while RIPT is dominated by structurally and organoleptically similar compounds with high potency. Specifically, stale and musty smelling methoxybenzenes contributed the most to RIPT, while floral-, sweet-, and woody-smelling terpene alcohols, terpene ketones, and phenolic compounds were the predominant odorants in RAPT. Orthogonal partial least squares discriminant analysis revealed that linalool, α-ionone, 1,2,4-trimethoxybenzene, 1,2,3-trimethoxy-5-methylbenzene, 1,2,3,4-tetramethoxybenzene, and 1,2,3-trimethoxybenzene underwent remarkable changes during pile fermentation and could be used as potential odor-active markers for RIPT and RAPT discrimination. The comprehensive aroma characterization of pu-erh tea and determination of the effect of pile fermentation on odorant alteration herein will provide guidance for pu-erh tea flavor quality control and evaluation.
Subject(s)
Camellia sinensis/chemistry , Flavoring Agents/chemistry , Odorants/analysis , Adult , Female , Fermentation , Food Handling , Gas Chromatography-Mass Spectrometry , Humans , Male , Olfactometry , Plant Leaves/chemistry , Smell , Tea/chemistry , Young AdultABSTRACT
Predominant contributors to thermally-induced off-notes in muskmelon juice were investigated by combination of sensory evaluation, GC-olfactometry (GC-O), multidimensional GC, odor activity value (OAV) calculation and addition experiments. "Fermented" and "sulfurous" were revealed as the dominant heat-induced offensive off-notes, and fundamental heat-led changes in odorant compositions were observed. Comparative aroma extract dilution analysis revealed that the off-flavors were mainly caused by newly heat-formed compounds with extremely low odor threshold and unpleasant smells. These included volatile sulfur compounds with "rotten" odors, Strecker aldehydes having "fermented" notes, and heterocyclics exhibiting "roasted" smells. Specifically, dimethyl sulfide, methional, methanethiol, dimethyl trisulfide, dimethyl disulfide, and acetaldehyde were identified as the predominant off-note contributors, among which DMS was the most important one, showing the highest OAV. Multiple extraction techniques, GC-O coupling to GCâ¯×â¯GC-QTOF-MS and OAV calculation are powerful tools for accurate location and reliable identification of trace and key off-odorants in natural complex matrices.
Subject(s)
Cucumis melo/chemistry , Fruit and Vegetable Juices/analysis , Odorants/analysis , Volatile Organic Compounds/analysis , Gas Chromatography-Mass Spectrometry/methods , Hot Temperature , Humans , Olfactometry/methods , Smell , TasteABSTRACT
Chemiluminescence (CL) reactions usually take place in a severely restricted pH regime, thereby confining their application in media at different pH. In this paper, the CL behavior of tobacco-methanol extract (TME) was explored. Surprisingly, TME exhibited CL behavior upon mixing with Fe2+/H2O2, HRP/H2O2 and gold nanoparticles/H2O2 oxidation systems, i.e., in acidic, neutral and alkaline solution respectively. Addition of different reactive oxygen species scavengers verified that the hydroxyl radical (OH) triggers TME CL reactions. Then, the CL behavior of TME was applied to determine OH in tetrachloro-1,4-benzoquinone (TCBQ)/H2O2 system in acidic, neutral and alkaline solutions. CL intensity correlated most strongly (R2â¯=â¯0.99) with TCBQ concentration, which was used as a means to indirectly denote OH concentration. This implies that OH could be determined by a TME CL method in a semi-quantitative way regardless of pH value. Therefore, the TME CL method may be a promising method for OH determination in various OH-generating systems.
Subject(s)
Hydroxyl Radical/analysis , Luminescent Measurements/methods , Nicotiana/chemistry , Plant Extracts/chemistry , Hydrogen-Ion Concentration , Methanol/chemistry , Oxidation-Reduction , Spectrum AnalysisABSTRACT
Cooked off-flavor components were identified, and their formation mechanisms were studied in heat-treated melon juices. When flavor dilution analysis methods and odor activity values were used to evaluate the cooked off-flavor in heat-treated melon juice, four volatile sulfide compounds (VSCs) were identified as contributors to the cooked off-flavor: dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), dimethyl sulfide (DMS), and 3-(methylthio)propanal (MTP). The cooked off-flavor intensities of heated juices from thick-skinned melons were stronger than those in juices from thin-skinned melons. We conducted a comparative analysis of VSCs before and after heat treatment by adding unlabeled and labeled S-methylmethionine (SMM) and/or methionine (Met) to the original melon juices. DMS and MTP were formed from SMM and Met through nucleophilic substitution and Strecker degradation, respectively. DMDS and DMTS were partly formed through the oxidative degradation of methanethiol produced from Met. Moreover, SMM could accelerate degradation of Met by increasing the amount of dicarbonyl compounds during heat treatment.
Subject(s)
Cucurbitaceae/chemistry , Flavoring Agents/chemistry , Fruit and Vegetable Juices/analysis , Cooking , Fruit/chemistry , Gas Chromatography-Mass Spectrometry , Hot Temperature , Molecular Structure , Odorants/analysisABSTRACT
Glucocorticoids are effective to treat lymphoma and leukemia. Their effect in colon cancer remains far from clear. Here, we found that glucocorticoid receptor (GR) α protein level was dramatically lower in colon cancer than in lymphoma. Colon cell lines LoVo and HCT116 were GRα-rich and GRα was not detectable in HT29 or SW480. Dexamethasone significantly inhibited cell growth of GRα-rich cell lines and did not significantly affect GRα-negative cell lines. Dexamethasone induced apoptosis and increased chemosensitivity of GRα-rich cell lines. Knockdown of GRα significantly attenuated dexamethasone effects on cell growth, apoptosis and chemosensitivity. NF-κB p65 significantly correlated with GRα in colon cancer samples. Dexamethasone decreased NF-κB p65 activity. Knockdown of NF-κB p65 increased apoptosis. Our data demonstrate GRα protein level is dramatically lower in colon cancer than in lymphoma. Dexamethasone inhibits cell growth, induces apoptosis and enhances chemosensitivity in colon cancer, at least partly, via GRα and NF-κB.