Flavor Changing Research Articles

Distinguishing models with μ → e observables

Upcoming experiments will improve the reach for the lepton flavour violating (LFV) processes μ → eγ, μ → ee¯e\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ e\\overline{e}e $$\\end{document} and μA → eA by orders of magnitude. We investigate whether this upcoming data could rule out some popular TeV-scale LFV models (the type II seesaw, the inverse seesaw and a scalar leptoquark) using a bottom-up EFT approach. We take the data to be the twelve Wilson coefficients that experiments can constrain and in principle determine independently. In this 12-dimensional coefficient space, each model can only predict points in a specific subspace; for instance, flavour change involving singlet electrons is suppressed in the seesaw models, and the leptoquark induces negligible coefficients for 4-lepton scalar operators. Using the fact that none of these models can populate the whole region accessible to upcoming experiments, we show that μ → e experiments have the ability to rule them out.

A model with vectorlike fermions and U(1)X symmetry: CKM unitarity, b → s transitions, and prospect at Belle II

The updated analysis of the LHCb Collaboration on the lepton flavor violation suggests that the new physics should couple to muons and electrons with comparable magnitudes, resulting in the anomalies in both rare decay channels, b→sμ+μ− and b→se+e−. Meanwhile, the recent result of the Muon g−2 experiment with higher precision has increased the existing tension with the standard model prediction. In this paper, we consider an extension of the standard model with a new sector consisting of vectorlike fermions and two scalar charged under an extra U(1)X gauge symmetry. The exotic Yukawa interactions in this model lead to the quark mixing responsible for the additional contributions to the flavor changing neutral currents in B-meson decays, and solve the muon g−2 discrepancy. We derive the analytic expression of the new physics contributions to the Wilson coefficient C7 in the effective Hamiltonian, and point out that the CKM unitarity violation can be explained within this context. By calculating the branching ratio of the inclusive radiative B decay, the impact of current experimental data of the b→sγ transition on the model and the future prospect at the Belle II experiment are investigated. Taking into account the current data on the muon anomalous magnetic moment, the CKM unitarity violation, the constraints on the flavor observables relevant to the b→s transitions, the LHC searches for vectorlike quarks, and the perturbation limits of the couplings, the viable parameter regions of the model are identified.

Microbiomics and volatile metabolomics-based investigation of changes in quality and flavor of oat (Avena sativa L.) silage at different stages.

This study aimed to analyze the fermentation quality, microbial community, and volatile metabolites of oat silage harvested at two different stages, while examining the correlation between microorganisms and volatile metabolites. Oats were harvested at two growth stages (pre-heading [PRH] and post-heading [POH] stages), followed by 90 days of natural fermentation, with 6 replicates per treatment. Pre- and post-silage samples were randomly selected for nutrient composition, fermentation parameters, microbial population, and high-throughput sequencing analysis. Volatile metabolomics analysis was also performed on samples after 90 days of fermentation to detect differences in flavor quality after silage. The effect of growth stage on the nutrient content of oats was significant, with pre-heading oats having higher crude protein and post-heading oats having higher water soluble carbohydrates content (p < 0.05). Following a 90-day fermentation period, the pH and ammonia nitrogen/total nitrogen levels in the PRH-90 (silage from pre-heading oats after 90 days of fermentation) group demonstrated a significant decrease (p < 0.05), whereas the lactic acid content was notably higher compared to the POH-90 (silage from post-heading oats after 90 days of fermentation) group (p <0.05). Lactiplantibacillus dominated in the PRH-90 group and Enterococcus dominated in the POH-90 group, with abundances of (> 86%) and (> 87%), respectively. The differential volatile metabolites of the two treatment groups were dominated by esters and terpenoids, and the differences in flavor were mainly concentrated in sweet, green, and fruity odors. The results of Kyoto encyclopedia of genes and genomes pathway enrichment analysis demonstrated three major metabolic pathways: phenylpropanoid biosynthesis, phenylalanine metabolism, and biosynthesis of secondary metabolites. Specific microorganisms were significantly correlated with flavor indicators and flavor metabolites. Lactiplantibacillus was significantly positively correlated with flavor substances indicating sweet and fruity flavors, contributing to good flavor, while Enterococcus was significantly and positively correlated with flavor substances indicating bad flavors. In summary, growth stage had significant effects on nutritional components, fermentation parameters and flavor quality of oats, with the fermentation process dominated by Lactiplantibacillus leading to good flavor, while the fermentation process dominated by Enterococcus led to the development of poor flavor.

An electron-muon collider: what can be probed with it?

Collisions of electrons against muons provide a very clean environment for many beyond SM signals. We consider the case of two-to-two flavor changing processes that are absent in the SM. The sensitivity of the e-muon collider to the four-fermion dimension six operators is about the same order of magnitude as the one based on low energy measurements.

Constraining BSM discrete flavor symmetries with heavy scalar searches at colliders

Discrete Flavor Symmetries are often employed in BSM constructions to successfully recreate fermion masses and mixing patterns through several known mechanisms. Obvious constraints on these types of scenarios are the non-observation of Flavour Changing Neutral Currents which set stringent limits. In this talk I will discuss the strategy of using the scalar sector phenomenology predicted by such BSM models, and its correlation with the dark matter sector, to further strengthen the constraints by exploiting the large data available from heavy scalar searches in colliders including recent likelihood profiles provided by ATLAS and CMS.

Formation of fluorescent substances and correlation with process flavor changes of dehydrated Maillard reaction intermediates of peanut protein hydrolysates

Maillard reaction intermediates (MRIs) derived from peanut protein hydrolysates (PPH) and xylose (Xyl) were prepared using the water bath combined with spray drying and vacuum drying. The monitoring of free amino content, browning precursors, and taste characteristics was carried out throughout the thermal treatment at low temperature, where the Maillard reaction process was slowed down, and the formation and degradation of MRIs were dynamically balanced at low conversion rates. The reaction between amino compounds and the reducing sugars contributed to the increased taste characteristics during the early phase of Maillard reaction. Fluorescence intensity was reduced after reaching its maximum value and browning intensity was significantly increased during vacuum drying, which confirmed that the Maillard reaction entered into an advanced stage. Vacuum drying also led to a significant increase in the total amount of volatile compounds in the subsequent thermal processing reaction (from 212.93 ng/g to 564.91 ng/g), which demonstrated that the higher fluorescence intensities resulted in the more accumulation of MRIs and better capabilities of flavor formation.

Interactions between phosvitin and aldehydes affect the release of flavor from Russian sturgeon caviar

The release mechanism of flavor during caviar storage was studied by the interaction between phosvitin and four aldehydes. Gas chromatography–mass spectrometry showed that the binding rate of phosvitin with 3-methylbutanal, nonanal, (E,Z)-2,6-nonadienal, and (E)-2-octenal decreased with an increase in the aldehyde concentrations. Among them, (E,Z)-2,6-Nonadienal (0.5 mM) had the highest binding rate (84.47%). The main quenching mechanism of (E,Z)-2,6-nonadienal with phosvitin was static quenching and the binding force comprised spontaneous hydrophobic interactions. An increase in the aldehyde concentrations reduced the α-helix content of phosvitin and led to aggregation of the microstructure of phosvitin. The results of molecular docking showed that tyr residue contributed the most to the binding of phosvitin to aldehydes. This study has elucidated the mechanism of the effect of caviar protein on changes in the caviar flavor during storage and provides effective strategies for regulation of caviar flavor during storage.

Review of Flavor Anomalies

Lepton flavor universality exists in the Standard Model, and hence any observation of the violation of this universality will be a hint for new physics. Recent experimental searches for processes violating this symmetry have attracted much attention among theorists and experimentalists alike. In recent years, such hints have been observed in flavor changing neutral current weak processes such as b→sll and charged current weak processes such as b→clν processes by collider experiments like Belle, Belle II, BaBar, LHCb, ATLAS, and CMS collaborations, where b,s,c are the bottom, strange, and charm quarks, respectively, and l,ν stand for lepton and the corresponding lepton neutrino, respectively. This article is a review of some of the interesting anomalies observed in the B-sector and includes decays of Bs mesons.

New Physics in CP violating and flavour changing quark dipole transitions

We explore CP-violating (CPV) effects of heavy New Physics in flavour-changing quark dipole transitions, within the framework of Standard Model Effective Field Theory (SMEFT). First, we establish the relevant dimension six operators and consider the Renormalisation Group (RG) evolution of the appropriate Wilson coefficients. We investigate RG-induced correlations between different flavour-violating processes and electric dipole moments (EDMs) within the Minimal Flavour Violating and U(2)3 quark flavour models. At low energies, we set bounds on the Wilson coefficients of the dipole operators using CPV induced contributions to observables in non-leptonic and radiative B, D and K decays as well as the neutron and electron EDMs. This enables us to connect observable CPV effects at low energies and general NP appearing at high scales. We present bounds on the Wilson coefficients of the relevant SMEFT operators at the high scale Λ = 5 TeV, and discuss most sensitive CPV observables for future experimental searches.

Spontaneous CP violation and mu -tau symmetry in two-Higgs-doublet models with flavour conservation

In multi-Higgs-doublet models, requiring simultaneously that (i) CP violation only arises spontaneously, (ii) tree level scalar flavour changing couplings are absent and (iii) the fermion mixing matrix is CP violating, can only be achieved in a very specific manner. A general approach with new clarifying insights on the question is presented. Considering the quark sector, that peculiar possibility is not viable on phenomenological grounds. We show that, considering the lepton sector, it is highly interesting and leads to viable models with mu -tau symmetric PMNS matrices. Phenomenological implications of the models, both for Dirac and Majorana (in a type I seesaw scenario) neutrinos, are analysed.

Metabolomic and transcriptomic integrated analysis revealed the decrease of monoterpenes accumulation in table grapes during long time low temperature storage

Low temperature is the commonly used technique for maintaining the quality of table grapes during postharvest storage. However, this technique could strongly affect the aromatic flavor of fruit. Monoterpenes are the key compounds contributing to the Muscat aromas of grapes. The detailed information and molecular mechanisms underlying the changes in monoterpenes during postharvest low temperature storage have not been thoroughly characterized. In this study, the effects of low temperature storage on the free and bound monoterpene profiles in four cultivars of table grape were determined at both the transcriptomic and metabolomic levels. A total of 27 compounds in both free and bound forms were identified in the four cultivars and showed quantitative differences between the cultivars. Hierarchical cluster and principal component analysis indicated that the free and bound monoterpene profiles were remarkably affected by the low temperature storage. The monoterpenes in the same biosynthesis pathway were clustered together and showed similar evolution trends during low temperature storage. And the content of most of free monoterpenes underwent a rapid decline during low-temperature storage at a certain stage, but the time was different in 4 grape cultivars. Transcriptomic analysis revealed that the expression of DXS, HDR, GPPS and TPS genes involved in the monoterpene synthesis pathway were consistent with the changes in the accumulation of monoterpene compounds. While the expression of HMGS, HMGR genes in MVA pathway and branch genes GGPPS and FPPS were negatively correlated with the accumulation of monoterpenes. The findings provide new insights into the underlying mechanisms of the berry aroma flavor change during low temperature storage.

Bounds on quark mixing, [formula omitted] and Z − Z′ mixing angle from flavor changing neutral processes in a 3-3-1 model

Meson and anti-meson mixing processes constitute an important source of constraints on models that give tree level contributions to flavor violating neutral processes. In electroweak SU(3)L×U(1)N models, where anomaly cancellation requires that one family of quarks transforms differently from the other ones, processes involving flavor changing neutral currents gain tree level contributions mediated by gauge and scalar fields. Here, we firstly investigate the contributions of the neutral scalar that mimics the standard Higgs to the K0−K¯0, B0−B¯0, and D0−D¯0 mixing processes and confront our predictions with experiments. The results will determine the quark mixing matrices VLu,d. In possession of this information we, next, evaluate the contributions of the neutral gauge bosons Z′ and Z to the K0−K¯0, B0−B¯0, and D0−D¯0 processes. This realistic approach to meson transitions will provide severe bounds on MZ′ and Z−Z′ mixing angle.

Characterization of Key Odorants in Soy Sauce and Their Concentration Changes during Storage

To explore the key odorants and their concentration changes in high-salt liquid-state fermentation soy sauce (HLFSS) during storage, solvent extraction coupled with solvent-assisted flavor evaporation was applied to isolate the volatiles in HLFSS, and the volatiles were analyzed by gas chromatograph-mass spectrometry-olfactory and gas chromatograph-flame ionization detector-olfactometry combined with the aroma extract dilution assay. A total of 37 odor-active compounds with flavor dilution (FD) factors ranging from 1 to 1024 were identified, and 23 aroma components with odor activity values ≥1 were considered as key odorants. Methional, 3-methylbutanoic acid, phenethyl alcohol, sotolon, 4-hydroxy-2-methyl-5-ethyl-3(2H)-furanone (HEMF), and 4-hydroxy-2,5-dimethylfuran-3(2H)-one (HDMF) had the highest FD factors of 1024. The results of quantitative analysis through the internal standard curve showed that the concentrations of HEMF, HDMF, acetic acid, 1-hydroxy-2-butanone, acetol, and furfuryl alcohol varied greatly during storage, so these compounds might be used as the indicators to determine the shelf life of HLFSS. The recombination experiment also confirmed the important contribution of these compounds. This result will provide valuable information for understanding the flavor changes of HLFSS.

Comparative Physiological and Transcriptome Analyses Reveal Mechanisms of Salicylic-Acid-Reduced Postharvest Ripening in 'Hosui' Pears (Pyrus pyrifolia Nakai).

Postharvest ripening of sand pear fruit leads to quality deterioration, including changes in texture, flavor, and fruit color. Salicylic acid (SA), an important defense-related hormone, delays fruit ripening and maintains fruit quality, but the underling mechanism remains unclear. Herein, we evaluated the efficacy of SA in delaying the ripening process of Pyrus pyrifolia cv. 'Hosui' pear fruit, as evidenced by the reduction in fruit weight loss, inhibition of firmness loss, cell wall degradation and soluble sugars, and retention of total phenols. Based on comparative transcriptomic data, a total of 3837 and 1387 differentially expressed genes (DEGs) were identified during room-temperature storage of control fruit and between SA-treated and control fruit, respectively. Further KEGG analysis revealed that the DEGs were mainly implicated in plant hormone signal transduction, starch and sugar metabolism, and cell wall modification. Moreover, exogenous SA treatment also altered the expression of many transcription factor (TF) families, including those in the ethylene-responsive factor (ERF), NAM, ATAF, CUC (NAC), basic helix-loop-helix (bHLH), basic leucine zipper (bZIP), and v-myb avian myeloblastosis viral oncogene homolog (MYB) families. Together, the results offer important insights into the role of SA-responsive genes in controlling fruit ripening in sand pears.

Kaili Red sour soup: Correlations in composition/microbial metabolism and flavor profile during post-fermentation

Flavor and chemical changes with microbial succession during Red-Sour-Soup (RSS) post-fermentation were urgent to be revealed for quality control. RSS post-fermentation could be divided into three stages according to acidity, nutrients exhausting and total colony counts, without coliform bacteria growth nor nitrite peak was observed. Lactobacillus acetotolerans induced over 50 % increase of lactic acid, finally conducing to the lactic acid-dominated sour taste of RSS. The volatile compounds totally increased by 25.70 % in chili sauce and 32.58 % in tomato sauce (p < 0.05). In early-/middle-stage (pH > 3.5), alcohols and short-chain fatty acids increased, and butyric acid with unpleasant odor became the maximum flavor contributor. Nevertheless, in late-stage (pH < 3.5), with the reduction of alcohols and fatty acids, esters, 2-nonanone and terpenoids with pleasant flavors increased by Clavispora lusitaniae, Pichia, Cladosporium delicatulum and Rozellomycota sp.. In conclusion, the post-fermentation, especially L. acetotolerans metabolism and aciduric fungal esterification were essential for RSS characteristic flavor formation.

Flavor changing neutral current processes and family discrimination in 3-3-1 models

In 3-3-1 models, anomaly cancellation requires that one of the three families of quarks transforms as triplet by , with the other two transforming necessarily as anti-triplet. This is an important feature of the model because, with it, we explain family replication. Thus it is mandatory to discriminate which of the families will transform as triplet by because the main consequence of anomaly cancellation in 3-3-1 models is the arising of processes violating flavor at the tree level by means of neutral currents mediated by gauge and scalar fields, and each case leads to different results. In this work, we consider the 3-3-1 model with right-handed neutrinos. Among the spectrum of 3-3-1 particles that contribute to the flavor changing neutral processes, there is a pseudoscalar that may be the lightest of the 3-3-1 particles, and this then should give the main contribution to such processes. We then calculate its contribution to the mixing transition and confront it with the current experimental results. We do this for the three cases in which one of the family of quarks transforms as a triplet by . According to our findings, each case leads to different constraints on the mass of the pseudoscalar, and the case in which the third family of quarks transforms as triplet seems to be the favoured one. We also obtain the most stringent bounds on the mass of the pseudoscalar of the model.

Microbial Succession and Flavor Changes During Fermentation of Semi-Dried Sea Bass (Lateolabrax maculatus)

ABSTRACT The Chinese traditional food, fermented semi-dried sea bass (FSSB), is famous for its unique flavor. The microbiota succession and flavor formation during fermentation remain unknown. This study utilized high-throughput sequencing to investigate the evolving microbiota and chemical determination to explore volatile compounds. The relevant abundance of microorganisms in the middle-fermented stage was significantly (p <.05) higher than that of the post-fermented stage. In addition, the main microbial phyla during fermentation were Firmicutes and Proteobacteria. In conclusion, this study contributes to understanding the changes in flavor substances during fermentation and the varying patterns of change among different floras.

Electroweak baryogenesis via top-charm mixing

We investigate a scenario of electroweak baryogenesis in the two Higgs doublet model with quark flavor mixing. In general, off-diagonal components of quark Yukawa interactions with additional Higgs bosons are strongly constrained by the data for flavor changing neutral currents. However, top-charm quark mixing is not the case, so that a large off-diagonal element can be taken, which can contribute to generating baryon asymmetry of the universe. It turns out that CP violating phases of the off-diagonal element in the source term in the Boltzmann equation are eliminated by the rephasing. This result is somewhat different from previous works on electroweak baryogenesis by flavor off-diagonal Yukawa couplings. Instead, we find that the absolute value of the top-charm off-diagonal element enhances CP violating phases in the Higgs potential, by which sufficient amount of the baryon number can be generated to explain the observed baryon asymmetry of the universe. We find that such a scenario is viable under the current experimental data. The model can be tested by the current and future measurements of various flavor experiments like Kaon rare decays, in addition to high energy collider experiments as well as gravitational wave observations. Characteristic predictions of our model would be deviations in Kaon rare decays. Branching ratios of K+→π+νν¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {K}^{+}\ o {\\pi}^{+}\ u \\overline{\ u} $$\\end{document} and KL→π0νν¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {K}_L\ o {\\pi}^0\ u \\overline{\ u} $$\\end{document} can deviate by the order of 10% and 1%, respectively, which may be tested at future Kaon experiments such as NA62 and KOTO step-2.

Transcriptomic analysis and volatile profiling reveals the regulatory mechanism of flavor volatiles in fresh-cut potatoes

ABSTRACT The potato (Solanum tuberosum L.) is one of the most edible vegetables worldwide. The cutting process disrupts the internal structure of several volatile substances that prompt flavor changes in fresh-cut potatoes. Understanding the composition of volatiles along with their biosynthesis mechanism is important to preserve original potato flavor during processing technology. This study characterized the volatile profiles and gene expression of fresh cut potato shreds at 0 hour (CK) and after 4 hours of storage (CK4). According to volatile profiling, alkanes were found to be the most abundant volatiles, followed by alcohols, aldehydes, esters, furans, and quinone. The abundance level of these volatiles was reduced many folds in CK4 potato shreds except for specific alkenes such as hexane, 1,3-hexadiene, and 1,6-octadiene. The transcriptome analysis revealed 5961 differentially regulated genes. An array of differential genes had functional annotations with biological responses to wounding, alcohol, water deprivation, and the molecular activity of acetyltransferase. In addition, most of these genes had pathway enrichment into the biosynthesis of secondary metabolites, alpha-linolenic acid metabolism, fatty acid biosynthesis, degradation, elongation, and metabolism. In particular, the many-fold differential regulation of the hydroperoxide pathway encoding genes probably yielded different volatile profiles that cause flavor disorders even after storage of fresh cut potato shreds for a few hours. Our results determined major flavor volatiles in fresh cut potato and identified important genes associated with the regulation of flavor volatiles in potato shreds. Our results will facilitate development of optimal management practices for preserving fresh-cut potatoes quality.

Unveiling improval changes in fried chicken flavor by glucose-curing treatment based on molecular sensory science

To gain insight into the improved flavor changes, the volatile flavor composition of fried chicken with glucose curing (500 mg/100 g meat) (FCWG), exhibiting the strongest meaty and roasted aromas, and that without curing (FCWOG) were comparatively analyzed. Solvent-assisted flavor evaporation combined with gas chromatography–mass spectrometry (GC–MS) and aroma extract dilution analysis by gas chromatography–olfactometry (GC–O), accurate quantitation, and odor-activity values (OAVs) calculation were performed. Both GC–MS or GC–O results revealed that levels of most aroma compounds were increased by the glucose-curing treatment. GC–MS results suggested that the glucose-curing treatment caused increased formation of the flavors via the Maillard reaction and lipid degradation, while the lipid degradation pathway was modified. In addition, GC–O results indicated a higher increase in the formation of the aroma compounds via the Maillard reaction by the glucose-curing treatment. Furthermore, quantitation and odor active values (OAVs) calculation showed glucose-curing had increased formation of the key odorants (OAV ≥ 1) (e.g., bis(2-methyl-3-furyl)disulfide, 2-acetylthiophene, 2-acetylthiazole, (E,E)− 2,4-decadienal, and methional), of which 2-acetylthiophene, bis(2-methyl-3-furyl)disulfide, and (E,E)− 2,4-decadienal are vital in fried chicken flavor. The results can provide guidance for improving fried chicken flavor by marination.