Formation of amino acid (l-leucine, l-phenylalanine) derived volatile flavour compounds by Moraxella phenylpyruvica and Staphylococcus xylosus in cured meat model systems

1998 ◽  
Vol 42 (1-2) ◽  
pp. 101-117 ◽  
Author(s):  
Jens K.S Møller ◽  
Lars L Hinrichsen ◽  
Henrik J Andersen
Keyword(s):  
Amino Acid ◽  
Model Systems ◽  
Flavour Compounds ◽  
Staphylococcus Xylosus ◽  
Cured Meat ◽  
Volatile Flavour

scholarly journals The Maillard Reaction as Source of Meat Flavor Compounds in Dry Cured Meat Model Systems under Mild Temperature Conditions

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 223
Author(s):  
Lei Li ◽  
Carmela Belloch ◽  
Mónica Flores
Keyword(s):  
Amino Acid ◽  
Volatile Compounds ◽  
Maillard Reaction ◽  
Meat Products ◽  
Model Systems ◽  
Flavor Compounds ◽  
Curing Conditions ◽  
Fermented Sausages ◽  
Dry Fermented Sausages ◽  
Cured Meat

Flavor is amongst the major personal satisfaction indicators for meat products. The aroma of dry cured meat products is generated under specific conditions such as long ripening periods and mild temperatures. In these conditions, the contribution of Maillard reactions to the generation of the dry cured flavor is unknown. The main purpose of this study was to examine mild curing conditions such as temperature, pH and aw for the generation of volatile compounds responsible for the cured meat aroma in model systems simulating dry fermented sausages. The different conditions were tested in model systems resembling dry fermented sausages at different stages of production. Three conditions of model system, labeled initial (I), 1st drying (1D) and 2nd drying (2D) and containing different concentrations of amino acid and curing additives, as well as different pH and aw values, were incubated at different temperatures. Changes in the profile of the volatile compounds were investigated by solid phase microextraction and gas chromatography mass spectrometry (SPME-GS-MS) as well as the amino acid content. Seventeen volatile compounds were identified and quantified in the model systems. A significant production of branched chain volatile compounds, sulfur, furans, pyrazines and heterocyclic volatile compounds were detected in the model systems. At the drying stages, temperature was the main factor affecting volatile production, followed by amino acid concentration and aw. This research demonstrates that at the mild curing conditions used to produce dry cured meat product volatile compounds are generated via the Maillard reaction from free amino acids. Moreover, in these conditions aw plays an important role promoting formation of flavor compounds.

scholarly journals Role of Chiral Configuration in the Photoinduced Interaction of D- and L-Tryptophan with Optical Isomers of Ketoprofen in Linked Systems

2021 ◽  
Vol 22 (12) ◽  
pp. 6198
Author(s):  
Aleksandra A. Ageeva ◽  
Ilya M. Magin ◽  
Alexander B. Doktorov ◽  
Victor F. Plyusnin ◽  
Polina S. Kuznetsova ◽  
...  
Keyword(s):  
Amino Acid ◽  
Excited States ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Dipole Interaction ◽  
The Body ◽  
Model Systems ◽  
Optical Isomers ◽  
Amino Acid Properties ◽  
Parkinson’S Diseases

The study of the L- and D-amino acid properties in proteins and peptides has attracted considerable attention in recent years, as the replacement of even one L-amino acid by its D-analogue due to aging of the body is resulted in a number of pathological conditions, including Alzheimer’s and Parkinson’s diseases. A recent trend is using short model systems to study the peculiarities of proteins with D-amino acids. In this report, the comparison of the excited states quenching of L- and D-tryptophan (Trp) in a model donor–acceptor dyad with (R)- and (S)-ketoprofen (KP-Trp) was carried out by photochemically induced dynamic nuclear polarization (CIDNP) and fluorescence spectroscopy. Quenching of the Trp excited states, which occurs via two mechanisms: prevailing resonance energy transfer (RET) and electron transfer (ET), indeed demonstrates some peculiarities for all three studied configurations of the dyad: (R,S)-, (S,R)-, and (S,S)-. Thus, the ET efficiency is identical for (S,R)- and (R,S)-enantiomers, while RET differs by 1.6 times. For (S,S)-, the CIDNP coefficient is almost an order of magnitude greater than for (R,S)- and (S,R)-. To understand the source of this difference, hyperpolarization of (S,S)-and (R,S)- has been calculated using theory involving the electron dipole–dipole interaction in the secular equation.

scholarly journals Sex-dependent dynamics of metabolism in primary mouse hepatocytes

2021 ◽  
Author(s):  
Luise Hochmuth ◽  
Christiane Körner ◽  
Fritzi Ott ◽  
Daniela Volke ◽  
Kaja Blagotinšek Cokan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
Sexual Dimorphism ◽  
New Drugs ◽  
Model Systems ◽  
Specific Gene ◽  
Primary Hepatocytes ◽  
Alcoholic Fatty Liver ◽  
Male And Female ◽  
Primary Mouse

AbstractThe liver is one of the most sexually dimorphic organs. The hepatic metabolic pathways that are subject to sexual dimorphism include xenobiotic, amino acid and lipid metabolism. Non-alcoholic fatty liver disease and hepatocellular carcinoma are among diseases with sex-dependent prevalence, progression and outcome. Although male and female livers differ in their abilities to metabolize foreign compounds, including drugs, sex-dependent treatment and pharmacological dynamics are rarely applied in all relevant cases. Therefore, it is important to consider hepatic sexual dimorphism when developing new treatment strategies and to understand the underlying mechanisms in model systems. We isolated primary hepatocytes from male and female C57BL6/N mice and examined the sex-dependent transcriptome, proteome and extracellular metabolome parameters in the course of culturing them for 96 h. The sex-specific gene expression of the general xenobiotic pathway altered and the female-specific expression of Cyp2b13 and Cyp2b9 was significantly reduced during culture. Sex-dependent differences of several signaling pathways increased, including genes related to serotonin and melatonin degradation. Furthermore, the ratios of male and female gene expression were inversed for other pathways, such as amino acid degradation, beta-oxidation, androgen signaling and hepatic steatosis. Because the primary hepatocytes were cultivated without the influence of known regulators of sexual dimorphism, these results suggest currently unknown modulatory mechanisms of sexual dimorphism in vitro. The large sex-dependent differences in the regulation and dynamics of drug metabolism observed during cultivation can have an immense influence on the evaluation of pharmacodynamic processes when conducting initial preclinical trials to investigate potential new drugs.

scholarly journals Single amino acid mutations effect Zika virus replication in vitro and virulence in vivo

2020 ◽  
Author(s):  
Nicole M. Collette ◽  
Victoria H.I. Lao ◽  
Dina R. Weilhammer ◽  
Barbara Zingg ◽  
Shoshana D. Cohen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Zika Virus ◽  
Model Systems ◽  
Single Amino Acid ◽  
Replication Rate ◽  
Adult Mice ◽  
Naturally Occurring ◽  
Viral Virulence

AbstractThe 2014-2016 Zika virus (ZIKV) epidemic in the Americas resulted in large deposits of next-generation sequencing data from clinical samples. This resource was mined to identify emerging mutations and trends in mutations as the outbreak progressed over time. Information on transmission dynamics, prevalence and persistence of intra-host mutants, and the position of a mutation on a protein were then used to prioritize 544 reported mutations based on their ability to impact ZIKV phenotype. Using this criteria, six mutants (representing naturally occurring mutations) were generated as synthetic infectious clones using a 2015 Puerto Rican epidemic strain PRVABC59 as the parental backbone. The phenotypes of these naturally occurring variants were examined using both cell culture and murine model systems. Mutants had distinct phenotypes, including changes in replication rate, embryo death, and decreased head size. In particular, a NS2B mutant previously detected during in vivo studies in rhesus macaques was found to cause lethal infections in adult mice, abortions in pregnant females, and increased viral genome copies in both brain tissue and blood of female mice. Additionally, mutants with changes in the region of NS3 that interfaces with NS5 during replication displayed reduced replication in the blood of adult mice. This analytical pathway, integrating both bioinformatic and wet lab experiments, provides a foundation for understanding how naturally occurring single mutations affect disease outcome and can be used to predict the of severity of future ZIKV outbreaks.Author summaryTo determine if naturally occurring individual mutations in the Zika virus epidemic genotype effect viral virulence or replication rate in vitro or in vivo, we generated an infectious clone representing the epidemic genotype of stain Puerto Rico, 2015. Using this clone, six mutants were created by changing nucleotides in the genome to cause one to two amino acid substitutions in the encoded proteins. The six mutants we generated represent mutations that differentiated the early epidemic genotype from genotypes that were either ancestral or that occurred later in the epidemic. We assayed each mutant for changes in growth rate, and for virulence in adult mice and pregnant mice. Three of the mutants caused catastrophic embryo effects including increased embryonic death or significant decrease in head diameter. Three other mutants that had mutations in a genome region associated with replication resulted in changes in in vitro and in vivo replication rates. These results illustrate the potential impact of individual mutations in viral phenotype.

scholarly journals The influence of roasting conditions on volatile flavour compounds in raw and roasted cashew kernels (Anacadium ocidentale) grown in Nigeria

2019 ◽  
Vol 11 (1) ◽  
pp. 1-10
Author(s):  
Olawale Paul Olatidoye ◽  
Taofik Akinyemi Shittu ◽  
Samuel Olusegun Awonorin ◽  
Emmanuel Sunday Akin Ajisegiri
Keyword(s):  
Volatile Compounds ◽  
Extraction Procedure ◽  
Consumer Acceptability ◽  
Volatile Fraction ◽  
Flavour Compounds ◽  
Overall Acceptability ◽  
Flame Ionization ◽  
Volatile Flavour ◽  
Steam Distillation Extraction ◽  
Temperature Time

The use of inappropriate temperature-time combinations during the roasting of nuts could lead to quality defects, such as burnt taste, short shelf-life, rancidity, and poor flavour. In this study, cashew kernels were roasted in a forced airflow-drying oven for 20, 40,and 60 min at 100, 120, 140, and 160°C. The productswere evaluated for volatile flavour compounds and the sensory evaluation of the roasted cashew kernelsat different roasting conditions. The volatile fraction was isolated using the combined steam distillation–extraction procedure and identified by gas chromatography–flame-ionization detection (GC-FID). The consumer acceptability test was carried out by 100 panellists using nine point hedonic scales to assess preferences for like or dislike, colour, taste, texture, flavour,and overall acceptability. It was found that there were significant differences in flavour compounds between the different conditions of roasting. Twenty-nine volatile compounds were identified in both fresh and roasted cashew kernelscomprising five main classes,which consist of 12 hydrocarbons, eight aldehydes, four ketones, three alcohols,and one acid. The volatile compounds(mg/100g) ranged from 5.03x10-2to 1.20 (2-butanone), 7.46x10-6to 1.85 (hexanal), 8.91x10-6to 1.94 (acetone), 6.74x10-1to 2.24 (benzaldehyde). The amount of generated volatile compounds increased astheroasting temperature and time increased. The consumer acceptability test revealed that samples roasted for 40 or 60 min at 140°C produced the most acceptable product in terms of all the measured attributes. The study showed that the roasting conditions produced acceptable cashew kernelsof desirable colour and superior flavour quality that enhance direct and commercial utilization.

Expression of a gene family in the dimorphic fungus Mucor racemosus which exhibits striking similarity to human ras genes

1990 ◽  
Vol 10 (12) ◽  
pp. 6654-6663
Author(s):  
W L Casale ◽  
D G Mcconnell ◽  
S Y Wang ◽  
Y J Lee ◽  
J E Linz
Keyword(s):  
Amino Acid ◽  
Cell Development ◽  
Amino Acid Sequences ◽  
Model Systems ◽  
Striking Similarity ◽  
Ras Proteins ◽  
Mucor Racemosus ◽  
Dimorphic Fungus ◽  
Transcript Accumulation ◽  
Ras Genes

Sporulation, spore germination, and yeast-hypha dimorphism in the filamentous fungus Mucor racemosus provide useful model systems to study cell development in eucaryotic cells. Three RAS genes (MRAS1, MRAS2, and MRAS3) from M. racemosus have been cloned, and their nucleotide sequences have been determined. The predicted amino acid sequences and the sizes of the three MRAS proteins exhibit a high degree of similarity with other ras proteins, including that encoded by H-ras, which have been implicated in regulation of proliferation and development in eucaryotic cells by mediating signal transduction pathways. The MRAS proteins show conservation of functional domains proposed for ras proteins, including guanine nucleotide interaction domains, an effector domain, a binding epitope for neutralizing antibody Y13-259, and the COOH-terminal CAAX box, which is a site of thiocylation and membrane attachment. Amino acid sequences unique to each MRAS protein occur adjacent to the CAAX box, consistent with the location of the hypervariable region in other ras proteins. Northern (RNA) analysis was used to study expression of the three MRAS genes in relation to cell development. Gene-specific probes for two of these genes, MRAS1 and MRAS3, hybridized to different 1.3-kb mRNA transcripts. The accumulation of these transcripts depended on the developmental stage, and this pattern was different between the two MRAS genes. No transcript for MRAS2 was detected in the developmental stages examined. The unique patterns of MRAS transcript accumulation suggest that individual MRAS genes and proteins may play distinct roles in cell growth or development.

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