Gas Chromatography-ion Mobility Spectrometry Research Articles

Insights into the Volatile Flavor Profiles of Two Types of Beef Tallow via Electronic Nose and Gas Chromatography–Ion Mobility Spectrometry Analysis

In the current study, an electronic nose (E-nose) and gas chromatography–ion mobility spectrometry (GC-IMS) were employed to investigate the volatile flavor compounds (VFCs) of intense flavor beef tallow (L) and ordinary beef tallow (P). The study results indicate that an E-nose combined with an LDA and GC-IMS combined with an OPLS-DA can effectively distinguish between the two types of beef tallow. Compared with ordinary beef tallow, the E-nose sensors of intense flavor beef tallow have stronger response signals to sulfides, terpenes, and nitrogen oxides. A total of 22 compounds contribute to making the flavor of intense flavor beef tallow more typical and richer; in contrast, ethyl acetate was the main aroma-active compound found in the ordinary beef tallow. Sulfur-containing compounds and terpenoids might be the key substances that cause sensory flavor differences between the two types of beef tallow. In conclusion, the results of this study clarify the characteristics and differences of the two types of beef tallow and provide an enhanced understanding of the differences in the flavors of the two types of beef tallow.

IMPACT OF BREATH SAMPLE COLLECTION METHOD AND LENGTH OF STORAGE OF BREATH SAMPLES IN TEDLAR BAGS ON THE LEVEL OF SELECTED VOLATILES ASSESSED USING GAS CHROMATOGRAPHY-ION MOBILITY SPECTROMETRY (GC-IMS).

The analysis of volatile organic compounds (VOCs) in exhaled air has attracted the interest of the scientific community because it provides the possibility of monitoring physiological and metabolic processes and non-invasive diagnostics of various diseases. However, this method remains underused in clinical practice as well as in research because of the lack of standardized procedures for the collection, storage and transport of breath samples, which would guarantee good reproducibility and comparability of results. The method of sampling, as well as the storage time of the breath samples in the polymer bags used for sample storage and transport, affect the composition and concentration of VOCs present in the breath samples. The aim of our study was to compare breath samples obtained using two methods with fully disposable equipment: Haldane sampling tube intended for direct breath collection and breath samples exhaled into a transparent Tedlar bag. The second task was to monitor the stability of selected compounds of real breath samples stored in a Tedlar bag for 6 hours. Gas chromatography - ion mobility spectrometry (GC-IMS) implemented in the BreathSpec® device was used to analyse exhaled breath. Our results showed a significant difference in the signal intensity of some volatiles when taking a breath sample with a Haldane tube and a Tedlar bag. Due to its endogenous origin, acetone levels were significantly higher when the Haldane tube sampler was used while elevated levels of 2-propanol and unidentified VOC in the Tedlar bag samples likely originated from contamination of the Tedlar bags. The VOC stability study revealed compound-specific signal intensity changes of the selected VOCs with storage time in the Tedlar bags, with some volatiles showing increasing signal intensity during Tedlar bag storage. Our results highlight the importance of careful design and implementation of experiments and clinical protocols to obtain relevant and reliable results.

Characterization of the key volatile compounds in longjing tea (Camellia sinensis) with different aroma types at different steeping temperatures by GC‒MS and GC‒IMS

Longjing tea (Camellia sinensis), an iconic agricultural product distinguished by its geographical indication status, has gained much acceptance and consumption in China. The aroma types and steeping conditions of green tea are important factors influencing consumer acceptance. However, the effects of steeping conditions on tea samples with different aroma types are still unknown. Explanation of the above unknowns can provide new insights into the flavor variations of tea when consumed for optimal sensory enjoyment. Here, the aroma profiles of Longjing green teas with bean-like (DX) and fresh aroma (QX) types were analyzed using gas chromatography‒mass spectrometry (GC‒MS), gas chromatography–ion mobility spectrometry (GC‒IMS), and quantitative descriptive analysis (QDA). Geraniol, (E, E)-2,4-heptadienal and other 11 compounds contributed to the bean-like aroma, while heptanal-d, hexanal-d and other 4 compounds contributed to the fresh aroma. Further, the release patterns of volatiles at different steeping temperatures were also revealed. 12 volatiles led to the differences between the two aroma types of Longjing teas at different steeping temperatures. Most volatiles exhibited their aroma characteristics when the steeping temperature exceeded 80 °C. These results enhance the comprehension of green tea's aroma profile, thereby enabling consumers to approach tea drinking from a more scientific perspective.

Removal of fishy flavor in kelp (Laminaria japonica) by natural antioxidant soaking combined with microbial fermentation

Kelp (Laminaria japonica) is rich in resources and a variety of active substances. However, its fishy flavor, which is hard to remove, poses challenges to consumer preferences. This study investigated the removal of fishy odor from Saccharomyces cerevisiae SK1.008 fermented kelp and kelp treated with fermentation combined natural antioxidant soaking through gas chromatography-mass spectrometry (GC-MS), odor activity values (OAVs) and gas chromatography-ion mobility spectrometry (GC-IMS). A total of 79 and 72 substances were identified in kelp using GC-MS and GC-IMS analysis, respectively. There were 16 volatile compounds (VOCs) with OAV>1 which were identified as key contributors to fishy odor, including (E,Z)-2,6-nonadienal, 1-octen-3-one, (E,E)-2,4-octadienal, (E,E)-2,4-decadienal and (E)-2-nonenal et al. The GC-MS analysis revealed that the removal efficiency of unsaturated aldehydes and ketones was 73.3% in kelp treated by fermentation combined soaking. The hierarchical cluster analysis and principal component analysis (PCA) constructed by GC-IMS revealed that the blank kelp, fermented kelp and kelp treated with fermentation combined soaking can be distinguished by volatile compounds. This study provides a reference for establishing a long-term effective deodorization method.

Detection and treatment of VOCs in the food industry

Volatile organic compounds (VOCs) are common pollutants in the atmosphere, which will do some harm to the environment and the human body. At present, the detection and treatment of VOCs are mainly concentrated in chemical, petroleum, pharmaceutical, household and other industries, but few scholars have studied the management of VOCs emitted by food industry. According to the characteristics of VOCs emitted from food industry, this article summarizes the research progress of relevant detection methods (gas chromatography, gas chromatography-mass spectrometry, gas chromatography-ion mobility spectrometry, electronic nose technology) for VOCs emitted from food industry in recent years, focusing on the research progress, advantages, and disadvantages of destruction technology (combustion method, low temperature plasma technology, biological method), treatment and recovery technology (adsorption method, absorption method, condensation method, membrane separation method) and combination technology for VOCs emitted from food industry. Based on the understanding of various governance technologies and the relevant policy requirements of VOCs governance, the future research trends in this field are prospected.

Faecal Volatile Organic Compound Analysis in De Novo Paediatric Inflammatory Bowel Disease by Gas Chromatography-Ion Mobility Spectrometry: A Case-Control Study.

The gut microbiota and its related metabolites differ between inflammatory bowel disease (IBD) patients and healthy controls. In this study, we compared faecal volatile organic compound (VOC) patterns of paediatric IBD patients and controls with gastrointestinal symptoms (CGIs). Additionally, we aimed to assess if baseline VOC profiles could predict treatment response in paediatric IBD patients. We collected faecal samples from a cohort of de novo therapy-naïve paediatric IBD patients and CGIs. VOCs were analysed using gas chromatography-ion mobility spectrometry (GC-IMS). Response was defined as a combination of clinical response based on disease activity scores, without requiring treatment escalation. We included 109 paediatric IBD patients and 75 CGIs, aged 4 to 17 years. Faecal VOC profiles of paediatric IBD patients were distinguishable from those of CGIs (AUC ± 95% CI, p-values: 0.71 (0.64-0.79), <0.001). This discrimination was observed in both Crohn's disease (CD) (0.75 (0.67-0.84), <0.001) and ulcerative colitis (UC) (0.67 (0.56-0.78), 0.01) patients. VOC profiles between CD and UC patients were not distinguishable (0.57 (0.45-0.69), 0.87). Baseline VOC profiles of responders did not differ from non-responders (0.70 (0.58-0.83), 0.1). In conclusion, faecal VOC profiles of paediatric IBD patients differ significantly from those of CGIs.

GC–IMS facilitates identification of carbapenem-resistant Klebsiella pneumoniae in simulated blood cultures

This study aimed to identify carbapenem-resistant Klebsiella pneumoniae (CRKP) based on changes in levels of its volatile organic compounds (VOCs) in simulated blood cultures (BCs) using the gas chromatography–ion mobility spectrometry (GC–IMS) technique. A comprehensive analysis of volatile metabolites produced by Klebsiella pneumoniae (K. pneumoniae) in BC bottles was conducted using GC–IMS. Subsequently, the released VOCs were analyzed to examine differences in VOC release between CRKP and carbapenem-susceptible Klebsiella pneumoniae (CSKP). A total of 54 VOCs were detected, of which 18 (6 VOCs found in both monomer and dimer forms) were successfully identified. The VOCs produced by K. pneumoniae in BC bottles (BacT/ALERT® SA) were primarily composed of organic acids, alcohols, esters, and ketones. The content of certain VOCs was significantly different between CRKP and CSKP after the addition of imipenem (IPM). Moreover, the inclusion of carbapenemase inhibitors facilitated the identification of carbapenemase-producing K. pneumoniae based on the variations in VOCs. This study demonstrates the utility of GC–IMS technology in identifying CRKP, and reveals that changes in VOCs are closely related to the growth and metabolism of K. pneumoniae, indicating that they can be leveraged to promote early identification of CRKP bacteremia. However, further in-depth studies and experiments are needed to validate our findings.

Geographical traceability of flavor compounds in Chinese mitten crab (Eriocheir sinensis): Implications for quality differentiation, authenticity assessment, and mechanism research

Geographical traceability plays a crucial role in ensuring quality assurance, brand establishment, and the sustainable development of the crab industry. In this study, we examined the possibility of using gas chromatography-ion mobility spectrometry with multivariate statistical authenticity analysis to identify the origin of crabs from five sites downstream of the Yangtze River. Significant variations were observed in the levels of alcoholic flavor compounds in the hepatopancreas and muscles of crabs from different geographical locations, and a support vector machine exhibited discriminant ability with 100% accuracy. These flavor variations exhibited significant correlations with the types and concentrations of elements within the crabs, as well as with free amino acids. This study offers a practical approach for determining the geographical traceability of Chinese mitten crabs and elucidates the role of elements in flavor modulation, thereby providing innovative strategies to enhance the efficiency of crab farming.

Application of GC-IMS, GC-MS, and LC-MS/MS techniques to a comprehensive systematic study on the flavor characteristics of different muscles in the yak

This study aims to explore the key metabolites and metabolic pathways related to the formation of flavor in yak meat, laying the foundation for in-depth analysis of the composition of yak meat and improving meat quality. This study selected six healthy 4-year-old male Tianzhu white yaks under the same growth conditions as the research subjects. The metabolites of three groups of longissimi dorsi (LD), triceps brachii (TB), and biceps femoris (BF) were analyzed and identified using gas chromatography–ion mobility spectrometry (GC-IMS), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that Tianzhu white yak meat contains abundant metabolites, and the VOC levels in BF muscles are higher than those in LD and TB muscles. The levels of 1-penten-3-one and 2-pentone in LD muscle are higher than in BF and TB muscle. The levels of 2-hexanol, 2-hexanol-D, and pyridine in TB muscles are higher than those in LD and BF muscles. The content of benzaldehyde, benzaldehyde D, 3-hydroxy-2-butane-D, 3-hydroxy-2-butanone, and mesitylene in BF muscle is higher than in LD and TB muscle. There is a significant difference in the enrichment degree of the glycolysis or gluconeogenesis pathways between LD muscles and the other two groups (BF and TB muscles). There were significant differences in the enrichment degrees of the d-glutamine and d-glutamate metabolic pathways, the alanine, aspartate, and glutamate metabolic pathways between the TB muscles and the other two groups (BF and LD muscles). There is a significant difference in the enrichment degree of the niacin and nicotinamide metabolic pathways between BF and LD muscles. In addition, there were significant differences in the enrichment degree of the histidine metabolism pathway among the three groups of muscles. This study identified key metabolites related to differences in meat quality and flavor formation in different parts of the muscle tissue of Tianzhu white yak through metabolomics analysis, providing a theoretical basis for exploring the molecular regulatory mechanism and molecular breeding of yak meat flavor formation in the future, and also providing a reference for quality trait breeding in other beef cattle.

Discrimination and screening of volatile metabolites in atractylodis rhizoma from different varieties using headspace solid-phase microextraction-gas chromatography-mass spectrometry and headspace gas chromatography-ion mobility spectrometry, and ultra-fast gas chromatography electronic nose

Atractylodis rhizoma is a common bulk medicinal material with multiple species. Although different varieties of atractylodis rhizoma exhibit variations in their chemical constituents and pharmacological activities, they have not been adequately distinguished due to their similar morphological features. Hence, the purpose of this research is to analyze and characterize the volatile organic compounds (VOCs) in samples of atractylodis rhizoma using multiple techniques and to identify the key differential VOCs among different varieties of atractylodis rhizoma for effective discrimination. The identification of VOCs was carried out using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), resulting in the identification of 60 and 53 VOCs, respectively. The orthogonal partial least squares discriminant analysis (OPLS-DA) model was employed to screen potential biomarkers and based on the variable importance in projection (VIP ≥ 1.2), 24 VOCs were identified as critical differential compounds. Random forest (RF), K-nearest neighbor (KNN) and back propagation neural network based on genetic algorithm (GA-BPNN) models based on potential volatile markers realized the greater than 90 % discriminant accuracies, which indicates that the obtained key differential VOCs are reliable. At the same time, the aroma characteristics of atractylodis rhizoma were also analyzed by ultra-fast gas chromatography electronic nose (Ultra-fast GC E-nose). This study indicated that the integration of HS-SPME-GC–MS, HS-GC-IMS and ultra-fast GC E-nose with chemometrics can comprehensively reflect the differences of VOCs in atractylodis rhizoma samples from different varieties, which will be a prospective tool for variety discrimination of atractylodis rhizoma.

60Co γ‐radiation at low‐dose level alters volatile compounds of blueberry during storage

Summary60Co γ‐radiation was applied to blueberry fruits in an effort to investigate a safe, eco‐friendly and effective blueberry preservation technique. However, the preservation effects were variable depending on tissue tolerance to irradiation doses. Moreover, irradiation may cause off‐odour. In this study, we examined the effects of three low doses of 60Co γ‐radiation on the physical and flavour attributes of blueberry. The results showed that 60Co γ‐radiation did not significantly improve fruit quality but extend the shelf life up to 15 days at 25 °C and 30 days at 4 °C. Compared with the control group, the preservation effect of 0.5–1.0 kGy irradiation treatment on blueberry fruit was not obvious before 15 days but maintained 65% of fruit firmness and reduced the loss of nutrients afterwards at 4 °C. At 25 °C, irradiation treatment caused up to a 150% increase in polyphenol oxidase activity, which was relevant to colour changes in late storage. Headspace Gas Chromatography Ion Mobility Spectrometry (HS‐GC‐IMS) was applied, and 33 volatile organic compounds (VOCs) in blueberry treated with different radiation doses were identified, including 11 esters, 8 aldehydes, 7 alcohols, 6 ketones and other substances, which increased with increasing radiation dose. Radiation reduced the green taste of blueberry and promoted their ripening. Radiation above the level of 1.02 kGy led to the flavour deterioration of blueberry such as ethyl trans‐2‐butenoate. The side effects of radiation on the aroma of blueberry could be offset by low‐temperature storage. Blueberry stored at 4 °C contained more aldehydes with a heavier fresh/green aroma. Six aromas were proposed to be characteristic odour markers of radiated blueberry.

Evaluating the influence of high-temperature sterilization and pasteurization on volatile organic compounds in tomato stewed beef brisket: An analysis using gas chromatography-ion mobility spectrometry and multivariate statistical visualization

Thermal Sterilization processes, while essential for ensuring food safety, can potentially compromise the organoleptic qualities and flavor profiles of prepared dishes. The present research endeavors to conduct an investigation into the discrepancies of different sterilization methodologies on the volatile organic compounds (VOCs) present in Tomato Stewed Beef Brisket (TSBB). Employing gas chromatography-ion mobility spectrometry (GC-IMS) and the relative odor activity value (ROAV), this study analyzed Untreated (US), Pasteurized (PS), and High-temperature sterilized (HTSS) TSBB samples. A total of 59 VOCs were identified, with aldehydes (37.2%), ketones (22.0%), and esters (17.5%) being the major contributors to the characteristic VOCs of TSBB.Principal component analysis (PCA) revealed significant distinctions between the US and HTSS. Furthermore, orthogonal partial least squares discriminant analysis (OPLS-DA) and partial least squares discriminant analysis (PLS-DA) collectively elucidated the discrepancies of VOCs from different thermal sterilization processes. The ROAV results indicated the presence of 21, 23, and 24 essential VOCs (ROAV>1) in the US, PS, and HTSS groups, respectively. Notably, High-temperature Sterilization significantly increased the aldehyde content, while Pasteurization augmented the ester content, specifically ethyl acetate-D and butyl acrylate-M. Overall, the findings indicate that High-temperature Sterilization exerted the most profound negative impact on the flavor profile of TSBB.This study provides a theoretical reference and practical basis for selecting the optimal sterilization process for prepared dishes, thereby contributing to the preservation of desirable organoleptic qualities and establishing a methodological framework for examining discrepancies in volatile organic compounds arising from divergent sterilization processes of TSBB.

Analysis of Volatile Aroma Components in Different Parts of Shiitake Mushroom (Lentinus edodes) Treated with Ultraviolet C Light-Emitting Diodes Based on Gas Chromatography-Ion Mobility Spectroscopy.

Further assessment of ultraviolet C light-emitting diode (UVC-LED) irradiation for influencing shiitake mushrooms' (Lentinus edodes) volatile and sensory properties is needed. In this study, a comparison of UVC-LED irradiation treatment on the flavor profiles in various parts of shiitake mushrooms was conducted using gas chromatography-ion mobility spectrometry (GC-IMS) and sensory analysis. Sixty-three volatile compounds were identified in shiitake mushrooms. The fresh shiitake mushrooms were characterized by the highest values of raw mushroom odors. After UVC-LED treatment, the content of C8 alcohols decreased, especially that of 1-octen-3-ol, while the content of aldehydes increased, especially the content of nonanal and decanal. The score of fatty and green odors was enhanced. For fresh samples, the mushroom odors decreased and the mushroom-like odors weakened more sharply when treated in ethanol suspension than when treated with direct irradiation. The fruit odors were enhanced using direct UVC-LED irradiation for fresh mushroom samples and the onion flavor decreased. As for shiitake mushroom powder in ethanol suspension treated with UVC-LED, the sweaty and almond odor scores decreased and the vitamin D2 content in mushroom caps and stems reached 668.79 μg/g (dw) and 399.45 μg/g (dw), respectively. The results obtained from this study demonstrate that UVC-LED treatment produced rich-flavored, quality mushroom products.

Characteristic Flavor Substances of Guizhou Black Tea and the Environmental Factors Influencing Their Formation Using Stable Isotopes and Headspace Gas Chromatography-Ion Mobility Spectrometry

Characteristic Flavor Substances of Guizhou Black Tea and the Environmental Factors Influencing Their Formation Using Stable Isotopes and Headspace Gas Chromatography-Ion Mobility Spectrometry

Removal of Cu (II) by ion exchange resin and its re-utilization of the residual solution from the distilled Lycium barbarum wine

In order to re-utilize the residual from the distillation of the Chinese wolfberry wine and reduce the environmental pollution, the residual is firstly filtered by the ceramic membrane of 50 nm, then the Cu (II) has transferred from the distillation is removed using the ion exchange resin, and the treated solution is recombined with the distilled liquor to make the Chinese wolfberry brandy and the comparison has conducted on the physicochemical properties, antioxidant activity and flavor compounds between the recombined brandy and the finished brandy. The results indicate that the Cu (II) was effectively removed by ceramic membrane combined with the D401 resin. Compared with finished brandy, the recombined brandy contains high contents of polysaccharides, phenols and flavonoids, thus contributing to the improvement of antioxidant capacity. The gas chromatography-ion mobility spectrometry (GC-IMS) reveals that 25 volatile compounds like esters and alcohols have identified in the brandy samples, and the differences are significant between the recombined and the finished brandy. In summary, the distilled residual from the Chinese wolfberry wine might be re-used after the appropriate treatment so as to reduce the discharge and environmental pollution.

Impact of thermal ultrasound on enzyme inactivation and flavor improvement of sea cucumber hydrolysates

In this study, the effects of the thermal ultrasonic enzyme inactivation process on flavor enhancement in sea cucumber hydrolysates (SCHs) and its impact on the inactivation of neutral proteases (NPs) were investigated. The body wall of the sea cucumber was enzymatically hydrolyzed with NPs. On the one hand, the structure of NPs subjected to different enzyme inactivation methods was analyzed using ζ-potential, particle size, and Fourier transform infrared (FT-IR) spectroscopy. On the other hand, the microstructure and flavor changes of SCHs were examined through scanning electron microscopy, E-nose, and gas chromatography-ion mobility spectrometry (GC-IMS). The results indicated that thermal ultrasound treatment at 60 °C could greatly affect the structure of NPs, thereby achieving enzyme inactivation. Furthermore, this treatment generated more pleasant flavor compounds, such as pentanal and (E)-2-nonenal. Hence, thermal ultrasound treatment could serve as an alternative process to traditional heat inactivation of enzymes for improving the flavor of SCHs.

An Evaluation of the Impact of 60Co Irradiation on Volatile Organic Compounds of Olibanum Using Gas Chromatography Ion Mobility Spectrometry.

Olibanum is a resinous traditional Chinese medicine that is directly used as a powder. It is widely used in China and is often combined with other traditional Chinese medicine powders to promote blood circulation and relieve pain, as well as to treat rheumatism, rheumatoid arthritis, and osteoarthritis. Powdered traditional Chinese medicine is often easily contaminated by microorganisms and 60Co irradiation is one of the good sterilization methods. Volatile organic compounds (VOCs) are the main active ingredient of olibanum. The aim of this study was to validate the optimum doses of 60Co irradiation and its effect on VOCs. 60Co irradiation was applied in different doses of 0 kGy, 1.5 kGy, 3.0 kGy, and 6.0 kGy. Changes in VOCs were detected using gas chromatography ion mobility spectrometry. A total of 81 VOCs were identified. The odor fingerprint results showed that, with an increase in irradiation dose, most of the VOCs of olibanum changed. Through principal component analysis, cluster analysis, and partial least squares discriminant analysis, it was demonstrated that, at 1.5 kGy, the impact of radiation on the VOCs of olibanum was minimal, indicating this is a relatively good irradiation dose. This study provides a theoretical basis for the irradiation processing and quality control of resinous medicinal materials such as olibanum and it also provides a good reference for irradiation technology development and its application to functional foods, thus making it both significant from a research perspective and useful from an application perspective.

A Novel Strategy for Mixed Jam Evaluation: Apparent Indicator, Sensory, Metabolomic, and GC-IMS Analysis.

Jam is a popular traditional and modern food product for daily consumption. However, the benefits of mixed jams over single-fruit jams have not been thoroughly explored, with analyses limited to superficial indices. In this study, Xinjiang special Morus nigra L. and Prunus domestica L. were used as raw materials to prepare single-fruit and mixed jams, and their differences in antioxidants, organoleptic qualities, pH, texture, and color were analyzed. The dynamics of metabolites before and after thermal processing were assessed using untargeted metabolomics. The results indicate that the main metabolites were flavonoids, terpenoids, amino acids, phenolic acids, and carbohydrates. Flavonoid metabolites changed significantly after thermal processing, with 40 up-regulated and 13 down-regulated. During storage, polyphenols were the prominent differential metabolites, with fifty-four down-regulated and one up-regulated. Volatile aroma components were analyzed using gas chromatography-ion mobility spectrometry (GC-IMS); the aroma components E-2-hexenal, E-2-pentenal, 3-methylbutanal, 1-penten-3-ol, tetrahydro-linalool, 1-penten-3-one, hexyl propionate, isoamyl acetate, α-pinene, and propionic acid in mixed jam were significantly higher than in single-fruit jam. In this study, untargeted metabolomics and GC-IMS were used to provide a more comprehensive and in-depth evaluation system for jam analysis.

Towards optimizing the protocol for untargeted profiling of urine volatiles via gas chromatography-ion mobility spectrometry. A pilot study.

The analysis of volatile organic compounds (VOCs) present in various biological samples holds immense potential for non-invasive disease diagnostics and metabolic profiling. One of the biological fluids that are suitable for use in clinical practice is urine. Given the limited quantity of VOCs in the urine headspace, it's imperative to enhance their extraction into the gaseous phase and prevent any degradation of VOCs during the thawing process. The study aimed to test several key parameters (incubation time, temperature, and thawing) that can influence urine volatilome and monitor selected VOCs for their stability. The analysis in this study was performed using a BreathSpec® (G.A.S., Dortmund, Germany) device consisting of a gas chromatograph (GC) coupled with an ion mobility spectrometer (IMS). Testing three different temperatures and incubation times yielded a low number of VOCs (9 out of 34) that exhibited statistically significant differences. However, examining three thawing conditions revealed no VOCs with statistically significant changes. Thus, we conclude that urine composition remains relatively stable despite exposure to various thermal stresses.

GC-IMS and multivariate analyses of volatile organic components in different Chinese breeds of chickens

This study examined the difference in volatile flavor characteristics among four different local breeds of chicken by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with multivariate analysis. In total, 65 volatile organic compounds (VOCs) were identified (17 aldehydes, 12 alcohols, 7 ketones, 5 esters, 2 acids, and 22 unidentified, i.e., 26.15% aldehydes, 18.46% alcohols, 10.77% ketones, 7.69% esters, 3.08% acids, and 33.84% unidentified), of which 43 were annotated. The chicken meats from the four breeds exhibited good separation in topographic plots, VOC fingerprinting, and multivariate analysis. Meanwhile, 20 different volatile components, with variable importance in projection value > 1, were selected as potential markers to distinguish different breeds of chicken by partial least squares discriminant analysis (PLS-DA). These findings provide insights into the flavor traits of chicken meat. Also, HS-GC-IMS combined with multivariate analysis can be a convenient and powerful method for characterizing different meats.