Search Results (138)

Temperature is the most critical factor in fish preservation. Superchilled storage represents a novel technology that effectively retards quality deterioration in aquatic products. This study investigated the flavor variation patterns and deterioration mechanisms in 16 northern pike (Esox lucius) samples during superchilled storage (−3 °C) based on analysis using gas chromatography-ion mobility spectrometry (GC-IMS) and ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). The results indicate that GC-MS analysis identified 25 key volatile flavor compounds. These comprised seven ketones, thirteen alcohols, aldehydes including 2-methylbutanal, esters such as 2-heptyl acetate and methyl butyrate, as well as nitrogen-containing compounds, exemplified by pyrazines and indole. Non-targeted metabolomics further revealed four pivotal metabolic pathways, glycerophospholipid metabolism, purine metabolism, the pentose phosphate pathway, and arginine biosynthesis. These metabolic pathways were found to regulate flavor changes through modulation of lipid oxidation, nucleotide degradation, and amino acid metabolism. Notably, the arginine biosynthesis pathway exhibited significant correlations with the development of characteristic cold-storage off-flavors, mediated by glutamate accumulation and fumarate depletion. This investigation provided a theoretical foundation for optimizing preservation strategies in cold-water fish species at the molecular level. Full article

A novel biodegradable food packaging material based on cassava thermoplastic starch (TPS) and polybutylene adipate terephthalate (PBAT) blends containing food preservatives was successfully developed using blown-film extrusion. This active packaging is designed to enhance the appearance, taste, and color of food products, while delaying quality deterioration. However, the incorporation of food preservatives directly influences consumer perception, as well as health and safety concerns. Therefore, this research aims to assess the risks associated with both intentionally added substances (IAS) and non-intentionally added substances (NIAS) present in the developed active packaging. The migration of both intentionally and non-intentionally added substances (IAS and NIAS) was evaluated using gas chromatography–mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Fifteen different volatile compounds were detected, with the primary compound identified as 1,6-dioxacyclododecane-7,12-dione, originating from the PBAT component. This compound, along with others, resulted from the polymerization of adipic acid, terephthalic acid, and butanediol, forming linear and cyclic PBAT oligomers. Migration experiments were conducted using three food simulants—95% ethanol, 10% ethanol, and 3% acetic acid—over a period of 10 days at 60 °C. No migration above the detection limits of the analytical methods was observed for 3% acetic acid and 10% ethanol. However, migration studies with 95% ethanol revealed the presence of new compounds formed through interactions between the simulant and PBAT monomers or oligomers, indicating the packaging’s sensitivity to high-polarity food simulants. Nevertheless, the levels of these migrated compounds remained below the regulatory migration limits. Full article

Background and Objectives: Breast cancer accounts for 12.5% of all new cancer cases in women worldwide. Early detection significantly improves survival rates, but traditional biomarkers like CA 15-3 and HER2 lack sensitivity and specificity, particularly for early-stage disease. Advances in metabolomics and machine learning, particularly explainable artificial intelligence (XAI), offer new opportunities for identifying robust biomarkers and improving diagnostic accuracy. This study aimed to identify and validate serum-based metabolic biomarkers for breast cancer using advanced metabolomic profiling techniques and a Light Gradient Boosting Machine (LightGBM) model. Additionally, SHapley Additive exPlanations (SHAP) were applied to enhance model interpretability and biological insight. Materials and Methods: The study included 103 breast cancer patients and 31 healthy controls. Serum samples underwent liquid and gas chromatography–time-of-flight mass spectrometry (LC-TOFMS and GC-TOFMS). Mutual Information (MI), Sparse Partial Least Squares (sPLS), Boruta, and Multi-Objective Feature Selection (MOFS) approaches were applied to the data for biomarker discovery. LightGBM, AdaBoost, and Random Forest were employed for classification and to identify class imbalance with the Synthetic Minority Oversampling Technique (SMOTE). SHAP analysis ranked metabolites based on their contribution to model predictions. Results: Compared to other feature selection approaches, the MOFS approach was more robust in terms of predictive performance, and metabolites identified by this method were used in subsequent analyses for biomarker discovery. LightGBM outperformed the AdaBoost and Random Forest models, achieving 86.6% accuracy, 89.1% sensitivity, 84.2% specificity, and an F1-score of 87.0%. SHAP analysis identified 2-Aminobutyric acid, choline, and coproporphyrin as the most influential metabolites, with dysregulation of these markers associated with breast cancer risk. Conclusions: This study is among the first to integrate SHAP explainability with metabolomic profiling, bridging computational predictions and biological insights for improved clinical adoption. This study demonstrates the effectiveness of combining metabolomics with XAI-driven machine learning for breast cancer diagnostics. The identified biomarkers not only improve diagnostic accuracy but also reveal critical metabolic dysregulations associated with disease progression. Full article

Most studies on the Arthrosphaera genus, or giant pill millipedes, focus on its taxonomy, distribution, and ecology. Therefore, this investigation aimed to explore the chemical composition and bioactive properties of the hemolymph of the giant pill millipede Arthrosphaera lutescens (Butler, 1872). Chemical characterization of hemolymph was performed using gas chromatography–mass spectrometry (GC-MS) and liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-MS Q-TOF), revealing a complex array of over 200 compounds. The bioactive properties of hemolymph were determined by using radical scavenging capacity (DPPH assay); antibacterial activity against human pathogens like Escherichia coli (Migula, 1895) Castellani and Chalmers 1919, Klebsiella pneumonia (Schroeter, 1886) Trevisan 1887, and Staphylococcus aureus (Rosenbach, 1884); and cytotoxicity against Dalton’s lymphoma ascites (DLA) cells using the trypan blue assay. The hemolymph showed radical scavenging properties and antibacterial and cytotoxic activity. Among the identified metabolites, 1,2-dimethoxy-13-methyl-[1,3]benzodioxolo[5,6-c]phenanthridine (DMBP) emerged as a promising candidate due to its high abundance and bioactivity profile, showcasing therapeutic potential against both lymphoma and S. aureus in further docking studies. Computational analysis identified key T-cell lymphoma targets, with molecular docking suggesting DMBP’s anticancer properties through interactions with proteins like AKT1 and mTOR. Additionally, docking revealed DMBP’s antibacterial effects via interactions with proteins such as Sortase-A and DNA gyrase. This research underscores the potential pharmaceutical applications of metabolites from giant pill millipedes. Full article

The characteristic minty-like aroma of ‘Rucheng Baimaocha’ black tea (RCBT) enhances the tea’s unique flavor profile, driving high demand among consumers. The dynamic changes in key aroma compounds in minty-like RCBT were elucidated by sensory evaluation and gas chromatography olfactometry quadrupole time of flight mass spectrometry (GC × GC-O-Q-TOF-MS). The results indicated that during processing, the aroma of RCBT transitions from a fresh to floral, sweet, and minty-like aroma. Among the 189 identified volatile compounds, alcohols constitute the predominant category (over 50%), with 71 compounds identified as key differential compounds across all stages. Aroma analysis revealed that 28 compounds with odor activity values (OAV) > 1 were the primary contributors during RCBT processing. Notably, minty-like odorants in RCBT were primarily derived from the metabolic pathways of the methylerythritol phosphate (MEP) and mevalonic acid (MVA), lipid oxidation, and phenylalanine. These findings offer theoretical insights for improving unique black tea quality and optimizing processing techniques. Full article

To compare the differences in meat quality between obese-type Chinese pig breeds and lean-type foreign pig breeds, we selected Taoyuan Black (TB) pigs and Duroc pigs at 180 and 210 days of age and analyzed their meat quality, chemical composition, and flavor compounds using an electronic tongue, chromatographic techniques, and two-dimensional gas chromatography-time-of-flight-mass-spectrometry (GC×GC-TOF-MS). A total of 16 main fatty acids, 18 main free amino acids, and 249 flavor compounds were identified. The results showed that TB pigs exhibited redder meat color, higher intramuscular fat, and lower shear force than Duroc pigs (p < 0.05). TB pigs displayed higher levels of flavor nucleotides, free amino acids, and monounsaturated fatty acids (p < 0.05). Furthermore, pigs at 180 days exhibited lower dripping loss and more flavor compounds than those at 210 days (p < 0.05). Electronic tongue analysis revealed higher umami values in TB pigs at 180 days of age. Among the flavor compounds in pork, the four compounds that contributed most significantly to flavor across all species were 2-nonenal, 2-octenal, heptanal, 2,3-butanedione, and 2-pentylfuran. These findings provide fundamental data and insight into pig production. Full article

Two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF MS) was employed to analyze the volatile flavor compounds (VOCs) of Tricholoma matsutake samples from six different geographical regions: CX (Chuxiong), DL (Dali), DQ (Diqing), JL (Yanji), SC (Xiaojin) and XZ (Linzhi). The result indicate that a total of 2730 kinds of VOCs were identified from the fruiting bodies of six T. matsutake samples. The primary types of volatile organic compounds identified were 349 alcohols, 92 aldehydes, 146 carboxylic_acids, 311 esters, 742 organoheterocyclic compounds, 630 hydrocarbons, 381 ketones, 51 organic acids, and 28 derivatives and organosulfur compounds. Furthermore, PCA and PLS-DA analysis from the GC×GC-ToF-MS showed that samples from different regions could be distinguished by their VOCs. Network analysis revealed that 33 aroma compounds were identified as markers for distinguishing the samples from the six regions. The sensory attributes sweet, fruity, green, waxy, and floral were found to be more significant to the flavor profile of T. matsutake. 1-Nonanol, 2-Nonanone, Nonanoic acid, ethyl ester, 1-Undecanol, 2-Undecanone, Octanoic acid, ethyl ester, 2H-Pyran, and tetrahy-dro-4-methyl-2-(2-methyl-1-propenyl)- primarily contribute to the differences in the aroma characteristics among six T. matsutake samples. The results also provide a theoretical and practical foundation for the flavor compounds of these precious edible fungi in different regions. Full article

Flavor is one of the crucial factors that influences the quality and consumer acceptance of baijiu. In this study, we analyzed the volatile organic compound (VOC) profiles of five different quality grades of Nongxiangxing baijiu (NXB), fermented during the summer of 2024, using 2D gas chromatography time-of-flight mass spectrometry (GC×GC–TOF-MS). We employed machine-learning (ML)-based classification and prediction models to evaluate the flavor. For TW, the scores of the sensory evaluation for coordination and overall evaluation were the highest. TW contained the highest concentration of ethyl caproate; we detected 965 VOCs in total, including several pyrazine compounds with potential health benefits. Principal component analysis (PCA) combined with orthogonal partial least squares discriminant analysis (OPLS-DA) enabled us to distinguish different samples, with eight VOCs emerging as primary contributors to the aroma of the samples, possessing variable importance in projection (VIP) values > 1. Furthermore, we tested eight ML models; random forest (RF) demonstrated the best classification performance, effectively discriminating samples based on their VOC profiles. The key VOC contributors that showed quality-grade specificity included 1-butanol, 3-methyl-1-butanol, and ethyl 5-methylhexanoate. The results elucidate the flavor-based features of NXB and provide a valuable reference for discriminating and predicting baijiu flavors. Full article

Vitamin E deficiency (VED) represents a common micronutrient deficiency in dairy cows (DCs), leading to severe degenerative diseases, oxidative stress, immune dysfunction, and various health issues, ultimately causing significant economic losses for the global dairy sector. Accordingly, our objective was to explore the metabolic features of VED-afflicted cows by combining the untargeted gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) and targeted liquid chromatography-mass spectrometry (LC-MS) to identify effective serum VED biomarkers. Untargeted GC-TOF-MS analysis identified 31 differential metabolites (DMs): 20 were overexpressed and 11 were suppressed in the VED group compared to the healthy control group. These DMs were enriched in six major metabolic pathways: glycine, serine, and threonine; alanine, aspartate, and glutamate; cysteine and methionine; tyrosine; primary bile acid biosynthesis; and nitrogen metabolisms. These outcomes show that VED significantly disrupts amino acid/lipid/energy metabolism pathways in DCs. Further targeted LC-MS quantification revealed significant alterations in key metabolites, including increased levels of norepinephrine, glycine, cysteine, and L-glutamine, as well as a significant reduction in cholesterol concentrations. Binary logistic regression analysis identified norepinephrine and cholesterol as strong candidate biomarkers for VED. Receiver operating characteristic curve analysis established outstanding diagnostic accuracy for norepinephrine and cholesterol (for both p < 0.001, area under the curve = 0.980 and 0.990, correspondingly), with sensitivities and specificities of 90% and 100%, respectively. In conclusion, this study integrates untargeted and targeted metabolomics approaches to reveal VED-caused metabolic disruptions in DCs, particularly in amino acid/lipid/energy metabolism pathways. Norepinephrine and cholesterol were identified as highly accurate serum VED biomarkers with excellent diagnostic performance. Early detection and timely intervention using these biomarkers could promote disease treatment and cow health, as well as productivity, and decrease economic losses. Full article

Mulberry leaves contain polysaccharides, phenols, alkaloids, and other active ingredients which have medicinal and edible value. In this study, fermented mulberry leaf powder was prepared by solid-state fermentation using Pediococcus pentosaceus JC30. The effects of the fermentation on the phytochemical, flavor characteristics, phenolics, and antioxidant activity of mulberry leaves were studied. The results showed that the content of γ-aminobutyric acid in fermented mulberry leaf powder (FMLP) increased by 6.73-fold and the content of phytic acid decreased by 11.16%. Ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) analysis showed that the fermentation of Pediococcus pentosaceus JC30 altered the phenolic composition of mulberry leaves, increasing the total free phenolic content by 88.43%. In particular, the contents of free phenols such as leucocyanidin, myricetin, and quercetin increased significantly and were positively correlated with antioxidant capacity. The fermentation of Pediococcus pentosaceus JC30 significantly enhanced the scavenging ability of DPPH free radicals, hydroxyl radicals, and the total reducing ability of mulberry leaves. Gas chromatography ion mobility spectrometry (GC-IMS) analysis showed that FMLP has an intense fruity and floral aroma, while having less grassy and earthy odor. The fermentation improved the phytochemical, flavor, and nutritional value of mulberry leaves, which provides more possibilities for the development of mulberry leaf products outside the sericulture industry. Full article

Bio-sniffers represent a novel detection technology that demonstrates significant potential in medical diagnostics. Specifically, they assess disease conditions and metabolic status through the detection of volatile organic compounds (VOCs) in exhaled breath. Unlike conventional methods such as gas chromatography-mass spectrometry (GC-MS) and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), bio-sniffers provide rapid, sensitive, and portable detection capabilities. In this review, we examine the metabolic pathways and detection methods of specific VOCs in the human body, and their roles as disease biomarkers, and focus on the detection principles, performance characteristics, and medical applications of two bio-sniffer types: electrical and optical sensors. Finally, we systematically discuss the current challenges facing bio-sniffers in VOC monitoring, outline future development directions, and provide suggestions for improving sensitivity and reducing environmental interference. Full article

This publication reports the controlled cultivation of Zanthoxylum chiloperone var. angustifolium Engl. (Rutaceae) in several growth substrates under controlled greenhouse conditions. This plant is well-known for its anti-Chagas (trypanocidal) activity, related to the presence of several β-carboline alkaloids. The metabolomic study of Z. chiloperone seedlings over two years of growth (2018–2020) was performed using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS). The canthin-6-one alkaloids, canthin-6-one and 5-methoxy-canthin-6-one, were putatively identified in Z. chiloperone extracts. Finally, in vitro and in silico studies of trypanocidal activity were performed, suggesting that canthin-6-one alkaloids could interact with the main pharmacological targets against Trypanosoma cruzi, cruzain protease, dihydroorotate dehydrogenase, lanosterol 14-alpha-demethylase, farnesyl diphosphate, and squalene synthases. Full article

The physicochemical and sensory properties of wines are influenced by several factors, starting in the vineyard and evolving during the winemaking stages. After bottling, variables such as bottle position, closure type, storage temperature, and storage time shape wine characteristics. In this study, red wines stored for approximately 0.5 and 3 years with natural cork, micro-agglomerated cork stoppers, and screw cap closures were analyzed. Various techniques were employed to investigate changes during bottle storage, including the determination of volatile components by comprehensive gas chromatography-mass spectrometry with time-of-flight analyzer (GC × GC-ToFMS), phenolic profile by ultra-high-performance liquid chromatography, coupled with tandem mass spectrometry (UHPLC-DAD-MSⁿ), general physicochemical parameters, the oxygen transfer rate of cork stoppers, and sensorial analysis performed by a trained panel. The results revealed that the type of closure created distinct environments within the bottles, slightly influencing both sensory attributes and chemical evolution of the red wines. These findings highlight the value of combining diverse analytical techniques to reveal closure-driven differences, with volatile compound profiling emerging as the most sensitive methodology. Additionally, this study emphasizes that differences modulated by the wine–closure pairing, which become more pronounced during storage, can serve as an oenological tool in the construction of a wine’s identity. Full article

Acetic acid bacteria (AAB) are a group of bacteria, most of which can produce pigments. However, the mechanism of pigment production by AAB is unclear. A strain of AAB, Gluconacetobacter tumulisoli FBFS 97, which can produce a large amount of brown pigment (BP), was isolated in our previous research. In the current study, it was found that the BP yield of the FBFS 97 strain was enhanced in the presence of tyrosine, and an intermediate of melanin, L-3,4-dihydroxyphenylalanine (L-DOPA), was identified using ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The structural properties of BP were analyzed by pyrolysis gas chromatography–mass spectrometry (Py-GC-MS). All these analyses suggest that BP may be eumelanin, a type of melanin. Then, the eumelanin biosynthetic pathway was investigated in the FBFS 97 strain, and three related genes with eumelanin including pheA, yfiH, and phhB in its genome were found and knocked out, respectively. The results showed that eumelanin production increased 1.3-fold in the pheA deletion mutant compared to the wild-type FBFS 97 strain, but when either yfiH or phhB was knocked out, the eumelanin production in the mutants was the same as that in the wild-type FBFS 97 strain. Finally, a possible biosynthetic pathway for eumelanin in the FBFS 97 strain is proposed. Full article

As an important crop in the world, dried pepper is widely used in various foods. However, the sensory quality, fruit shape index, edible index, nutrition index, and volatile components of dried pepper have not been comprehensively analyzed. This study elucidated the differences between different varieties of dried pepper and provided the basis for the selection of raw materials for different varieties of dried pepper products. The varieties with high scores in sensory evaluation were Henan new generation, Neihuang new generation, Chengdu Erjingtiao, India S17, and Honglong 12. The varieties with the highest fruit shape index, edible rate, and nutrition index were Chengdu Erjingtiao and Guizhou Erjingtiao. A total of 380 volatile organic compounds were identified by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry with headspace sampling (HS-GC-TOF MS), including 62 alcohols, 50 aldehydes, 68 ketones, 60 hydrocarbons, 99 esters, 18 acids, and 23 other substances such as pyrazoles and ethers. Full article