Tag: M.W=100-150

Petkevicius, Vytautas published the artcileA biocatalytic synthesis of heteroaromatic N-oxides by whole cells of Escherichia coli expressing the multicomponent, soluble di-iron monooxygenase (SDIMO) PmlABCDEF, Computed Properties of 14667-55-1, the main research area is sequence soluble di iron monooxygenase gene cluster pmlABCDEF; heteroaromatic oxide biocatalytic synthesis monooxygenase PmlABCDEF recombinant Escherichia.

Aromatic N-oxides (ArN-OX) are desirable biol. active compounds with a potential for application in pharmacy and agriculture industries. As biocatalysis is making a great impact in organic synthesis, there is still a lack of efficient and convenient enzyme-based techniques for the production of aromatic N-oxides. In this study, a recombinant soluble di-iron monooxygenase (SDIMO) PmlABCDEF overexpressed in Escherichia coli was showed to produce various aromatic N-oxides. Out of 98 tested N-heterocycles, seventy were converted to the corresponding N-oxides without any side oxidation products. This whole-cell biocatalyst showed a high activity towards pyridines, pyrazines, and pyrimidines. It was also capable of oxidizing bulky N-heterocycles with two or even three aromatic rings. Being entirely biocatalytic, our approach provides an environmentally friendly and mild method for the production of aromatic N-oxides avoiding the use of strong oxidants, organometallic catalysts, undesirable solvents, or other environment unfriendly reagents. The sequence of the p577A clone containing pmlABCDEF gene cluster was deposited in GenBank under the accession number MK037457.

Advanced Synthesis & Catalysis published new progress about DNA sequences (GenBank MK037457). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Computed Properties of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Wang, Zitai published the artcileEffects of microbial fermentation on enzyme activity and volatile properties of Massa Medicata Fermentata, Related Products of pyrazines, the main research area is Massa Medicata Fermentata volatile property microbial fermentation enzyme activity.

Aim : Massa Medicata Fementata (MMF) is a crude drug used in East Asia to treat anorexia and dyspepsia. It is prepared from wheat and several herbs through microbial fermentation using Aspergillus sp. and Rhizopus sp. There is great difference in the quality of com. MMF, and the microbes of MMF are suggested to affect its quality. We investigated the effects of microbial fermentation on the quality of MMF. Methods : Raw materials of MMF were mixed according to the ratio listed in the National Standard for Chinese Patent Drugs, and MMF was prepared using pure cultures of Aspergillus oryzae or Rhizopus oryzae. Digestive enzyme activities (α-amylase, protease, and lipase) and volatile compounds were measured using an anal. kit and GC-MS, resp. Results : Enzyme activity increased in MMF. MMF prepared with A. oryzae (MMF-A) showed higher α-amylase and lipase activities than that prepared with R. oryzae (MMF-R). Protease activity was marginally higher in MMF-R than in MMF-A. GC-MS anal. revealed that terpenoids decreased with fermentation; however, 2,3-butanediol, acetoin, and guaiacol were detected in MMF only. C8 compounds such as 1-octen-3-ol were higher in MMF-A than MMF-R; however, aromatic compounds such as 4-vinylguaiacol and pyrazines were higher in MMF-R than MMF-A. Conclusion : Microbial fermentation contributes to increased enzyme activity and changes in MMF volatiles. These properties of MMF were considerably affected by the microbes used, and it is proposed in this study that it is important to have microbial control in the production of com. MMF.

Traditional & Kampo Medicine published new progress about Amino acids Role: ANT (Analyte), BCP (Biochemical Process), BSU (Biological Study, Unclassified), ANST (Analytical Study), BIOL (Biological Study), PROC (Process). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Related Products of pyrazines.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Gao, Xianli published the artcileEnhancing selenium and key flavor compounds contents in soy sauce using selenium-enriched soybean, SDS of cas: 14667-55-1, the main research area is soybean soy sauce selenium flavor.

Selenium (Se) deficiency has become a global health threat. Se-enriched soybean was utilized to develop a Se-enriched soy sauce (SeSS), and the effects of Se-enriched soybean on the flavor compounds in SeSS were characterized with HPLC and SPME-GC-olfactometry/MS. Results showed that the contents of total selenium (11.1-fold), organic selenium (10.6-fold), small peptides (≤1 kDa, 25.4%), free amino acids (FAAs, 8.67%) and 22 aroma-active compounds in SeSS were significantly enhanced when compared to soy sauce prepared using ordinary soybean (SS, p < 0.05). Only the contents of 4-vinylguaiacol and acetic acid in SeSS were decreased by 30.5% and 17.7%. Further investigations found that Se-enriched soybean markedly enhanced the activities of acidic and alk. proteases in the koji and moromi (p < 0.05), which made more proteins and large peptides degrade into small peptides, sweet and bitter FAAs. Se-enriched soybean moromi promoted the reproduction of aroma-producing Lactobacillus plantarum and Zygosaccharomyces rouxii, and more aroma-active compounds were detected in SeSS. 4-Vinylguaiacol was reduced to 4-ethylguaiacol by L. plantarum and acetic acid was converted into acetate via esterification. The work developed a widely accessible selenium supplement and a novel method to improve the flavor of soy sauce. Journal of Food Composition and Analysis published new progress about Alcohols Role: ANT (Analyte), BSU (Biological Study, Unclassified), FFD (Food or Feed Use), ANST (Analytical Study), BIOL (Biological Study), USES (Uses). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, SDS of cas: 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Schwanz, Thiago G. published the artcileAnalysis of chemosensory markers in cigarette smoke from different tobacco varieties by GC×GC-TOFMS and chemometrics, HPLC of Formula: 14667-55-1, the main research area is chemosensory marker cigarette smoke flavor tobacco curing chemometric; Chemosensory markers; Comprehensive gas chromatography; Flavour; PLS-DA; Smoke; Tobacco.

Com. cigarettes are made from a blend of different tobacco varieties, which in turn are the results of different agronomic practices and post-harvest curing processes. The highly complex mixture of smoke compounds reflects each tobacco variety and the levels of sensory-relevant markers. Therefore, the aim of this work was to identify potential relevant chemosensory markers in the mainstream smoke of four main types of com. tobaccos and establish any possible relationship between them and the tobacco growing/curing practices. The tobacco samples were segregated into four segments: (1) three curing stages of flue-cured Virginia, (2) three curing stages of air-cured Burley, (3) three geo-regions of sun-cured Oriental and (4) three different process applied to tobacco. One hundred and twenty cigarettes (10 batches per flavor category) were produced and smoked under standard machine-smoking protocols. The mainstream smoke samples collected were extracted and analyzed by GC × GC TOFMS. The processed data was analyzed by partial least square discriminant anal. (PLS-DA) and the selectivity ratio was used to identify key chemosensory markers responsible for the four segments. All models had sensitivity and specificity equal to unity. Flue-cured Virginia (193 markers) and air-cured Burley (184 markers) showed a similar trend for O-heterocycles markers in the lighter leaf colors and N-heterocycles in the darker leaf colors post-processing, but they had compounds of different flavor descriptions, e. g. sweet and nutty. The three geo-regions of sun-cured Oriental (290 markers) also presented O-heterocycles markers in correlation with leaf sugar contents in addition of sucrose esters markers. The three unusually processed tobacco generated many chem. markers (436 markers), some derived from the so-called Cavendish fermentation process with sweet, spicy and peppery notes, whereas the dark fermented air-cured tobacco presented similar descriptors as air-cured Burley. In addition, some polycyclic aromatic hydrocarbons (PAH) were detected as markers from the fire-curing process. The PLS-DA with selectivity ratio evidenced total of 1098 chemosensory markers in cigarette smoke, in which 173 were tentatively identified.

Talanta published new progress about Biomarkers. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, HPLC of Formula: 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Xia, Xue published the artcileStructural diversity and concentration dependence of pyrazine formation: Exogenous amino substrates and reaction parameters during thermal processing of L-alanyl-L-glutamine Amadori compound, Application In Synthesis of 14667-55-1, the main research area is structural diversity pyrazine formation thermal processing; Amadori compound; Pyrazine; Thermal processing flavor; l-Alanyl-l-glutamine.

The Amadori compound of glucose and L-alanyl-L-glutamine (Ala-Gln-ARP) was prepared and characterized by UPLC-MS/MS and NMR. There were no pyrazines produced by heated Ala-Gln-ARP alone due to the asynchronicity of regenerated L-alanyl-L-glutamine and α-dicarbonyl compounds High temperature (130°C) and long reaction time could facilitate the 2,5-dimethylpyrazine formation at a small concentration (33.4 ± 3.47μg/L). The exogenous amino substrates would lower the formation temperature of pyrazines and make it to be generated effectively. Extra supplied L-alanyl-L-glutamine could generate 2,5-dimethylpyrazine at 110°C, while higher temperature of 140°C could strengthen the formation of 2,5-dimethylpyrazine (793 ± 119μg/L) and stimulate the generation of other pyrazines, including methylpyrazine and 2,6-dimethylpyrazine. The exogenous alanine, glutamic acid, and glutamine was also beneficial to enhance the pyrazines formation, especially the glutamic acid. Furthermore, alk. pH of thermal reaction made pyrazines increase significantly than in neutral medium and further enriched their species such as unsubstituted pyrazine and trimethylpyrazine.

Food Chemistry published new progress about Flavor enhancers. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Application In Synthesis of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Chen, Xuefeng published the artcileQuantitative analyses for several nutrients and volatile components during fermentation of soybean by Bacillus subtilis natto, SDS of cas: 14667-55-1, the main research area is Bacillus soybean glucose galactose isobutyric acid phenylalanine histidine fermentation; Bacillus subtilis natto; Fermentation stage; Isoflavones; Short chain fatty acids; Soybean fermentation; Volatile components.

This study is to reveal the variation of five pivotal substances, including polysaccharides, proteins, isoflavones, fatty acids and volatile components during the soybean fermentation process by Bacillus subtilis natto. After 96 h of soybean fermentation, the polysaccharide contents were significantly decreased, and the glucose and galactose contents showed the greatest decline in all the monosaccharide components. Moreover, isoflavone glycoside levels were decreased, while the isoflavone aglycon levels were increased following the fermentation In addition, the SCFAs contents were also significantly increased in comparison with the unfermented soybean. Furthermore, 16 amino acids and 36 volatile components were detected in the fermented soybean. Finally, 21 key compounds were identified through PCA and OPLS-DA anal. of total compounds in the fermentation process. These findings demonstrated that Bacillus subtilis natto had a significant influence on the biochem. profiles of soybean fermentation and consequently contributed to its unique quality.

Food Chemistry published new progress about Bacillus subtilis natto. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, SDS of cas: 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Li, Pei published the artcileFish meal freshness detection by GBDT based on a portable electronic nose system and HS-SPME-GC-MS, COA of Formula: C7H10N2, the main research area is fish meal freshness electronic nose HS SPME GC MS.

Abstract: The volatile compounds of super fresh, superior fresh, general fresh, corrupt and completely corrupt fish meal were studied by headspace solid-phase microextraction-gas chromatog.-mass spectrometry. Principal component anal. was used to analyze the sensor and gas chromatog.-mass spectrometry data, so as to study the resolution of sensor array. A total of 198 fish meal samples with different freshness were classified by the gradient boosting decision tree method, yielding a model between the sensor array data and the freshness index, such as the acid value and the volatile base nitrogen value. The gradient boosting decision tree model shows that the correlation between the predicted acid value by electronic nose and the measured acid value is 0.90 and the correlation between the predicted volatile base nitrogen value and the measured volatile base nitrogen is 0.97. The combination of an electronic nose and a pattern recognition method based on a gas sensor can predict the acid value and volatile base nitrogen of the freshness index and can detect the freshness of fish meal.

European Food Research and Technology published new progress about Fish meal. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, COA of Formula: C7H10N2.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Frank, Damian published the artcileVolatile and non-volatile metabolite changes in 140-day stored vacuum packaged chilled beef and potential shelf life markers, Computed Properties of 14667-55-1, the main research area is volatile nonvolatile metabolite vacuum package chill beef; Beef; Metabolites; Odor; PTR-MS; Vacuum packaging; Volatiles.

During storage of vacuum packaged chilled beef (VPCB), lactic acid bacteria become the dominant microflora, facilitating an extended shelf life. However, at some point, (bio)chem. and organoleptic changes render the meat unacceptable. In this investigation we evaluated volatile and non-volatile metabolite changes in VPCB after 84-, 98-, 120- and 140-days storage at ∼ – 1°C. After 140-days storage, the sensory, volatile and non-volatile data did not indicate spoilage. Minimal changes in volatile signatures of collected weep and on raw and grilled steaks were measured. Changes in selected non-volatile components indicated increased proteolysis (free amino acids, carnosine) and changes in organic acids (lactic, succinic) and nucleotide metabolism Rapid volatile profiling using proton transfer reaction mass spectrometry showed a clear progression of changes in selected compounds over the storage period. An increased concentration of ethanol and other compounds between 120 and 140 days, suggested that volatile changes may be a useful objective indicator of extended storage VPCB quality.

Meat Science published new progress about Alkanes Role: ANT (Analyte), BSU (Biological Study, Unclassified), ANST (Analytical Study), BIOL (Biological Study). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Computed Properties of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Zhu, Yu-Meng published the artcileRoasting process shaping the chemical profile of roasted green tea and the association with aroma features, SDS of cas: 14667-55-1, the main research area is roasting treatment far IR radiation sensory attributes tea; Aroma sensory evaluation; Drum roasting; Far-infrared irradiation; Flavonoids; Steamed green tea; Volatiles; Weighted correlation network analysis.

Roasting process impacts the chem. profile and aroma of roasted tea. To compare the impacts of far-IR irradiation and drum roasting treatments (light, medium and heavy degrees), the corresponding roasted teas were prepared from steamed green tea for chem. analyses and quant. descriptive anal. on aroma, and correlations between volatiles and aroma attributes were studied. There were 8 catechins, 13 flavonol glycosides and 105 volatiles quantified. Under heavy roasting treatments, most catechins and flavonol glycosides decreased, and aldehydes, ketones, furans, pyrroles/pyrazines, and miscellaneous greatly increased, while far-IR irradiated teas had distinct nutty aroma compared with the roasty and burnt odor of drum roasted teas. The weighted correlation network anal. result showed that 56 volatiles were closely correlated with the aroma attributes of roasted teas. This study reveals the differential chem. and sensory changes of roasted teas caused by different roasting processes, and provides a novel way for flavor chem. study.

Food Chemistry published new progress about Anthocyanins Role: ANT (Analyte), BSU (Biological Study, Unclassified), ANST (Analytical Study), BIOL (Biological Study). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, SDS of cas: 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Sioriki, Eleni published the artcileImpact of alkalization conditions on the phytochemical content of cocoa powder and the aroma of cocoa drinks, Formula: C7H10N2, the main research area is cocoa powder aroma drink alkalization phytochem content.

Alkalization is an important process in cocoa powder production that affects color and flavor. In this study, the impact of alkalization temperature (60, 70, 80, 90, 100°C), NaOH concentration (0.59, 1.17, 2.34, 3.59% weight/weight of cocoa powder) and alkalization time (1 and 10 min) on the physicochem. properties (pH, color) and phytochem. profile (theobromine, caffeine, epicatechin, catechin) of cocoa powder were investigated, while the aroma was studied on the corresponding cocoa drinks. High-performance liquid chromatog. coupled to an ultra-violet detector (HPLC-UV) was used for screening the non-volatiles and headspace solid – phase microextraction – gas chromatog. – mass spectrometry (HS-SPME-GC-MS) for the aromatic compounds Major changes of the cocoa properties occurred during the first minute of alkalization. Increase of temperature and alkali concentration generally reduced the levels of epicatechin and the lightness (L*), while the pH of the cocoa powder was affected by changing the alkali concentration On the other hand, the reddish (a*) and yellowish (b*) color component values and theobromine levels were not significantly affected by varying temperature and alkali concentration A higher temperature did not affect the concentration of the volatile compounds, while a decrease in certain chem. classes was observed by increasing the alkali concentration

LWT–Food Science and Technology published new progress about Aldehydes Role: ANT (Analyte), BSU (Biological Study, Unclassified), ANST (Analytical Study), BIOL (Biological Study). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Formula: C7H10N2.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem