Characteristic Volatile Compounds Research Articles

Controlling glycolysis to generate characteristic volatile organic compounds of lung cancer cells

Characteristic volatile organic compounds (VOCs) are anticipated to be used for the identification of lung cancer cells. However, to date, consistent biomarkers of VOCs in lung cancer cells have not been obtained through direct comparison between cancer and healthy groups. In this study, we regulated the glycolysis, a common metabolic process in cancer cells, and employed solid phase microextraction gas chromatography mass spectrometry (SPME–GC–MS) combined with untargeted analysis to identify the characteristic VOCs shared by cancer cells. The VOCs released by three types of lung cancer cells (A549, PC-9, NCI-H460) and one normal lung epithelial cell (BEAS-2B) were detected using SPME–GC–MS, both in their resting state and after treatment with glycolysis inhibitors (2-Deoxy-d-glucose, 2-DG/3-Bromopyruvic acid, 3-BrPA). Untargeted analysis methods were employed to compare the VOC profiles between each type of cancer cell and normal cells before and after glycolysis regulation. Our findings revealed that compared to normal cells, the three types of lung cancer cells exhibited three common differential VOCs in their resting state: ethyl propionate, acetoin, and 3-decen-5-one. Furthermore, under glycolysis control, a single common differential VOC—acetoin was identified. Notably, acetoin levels increased by 2.60–3.29-fold in all three lung cancer cell lines upon the application of glycolysis inhibitors while remaining relatively stable in normal cells. To further elucidate the formation mechanism of acetoin, we investigated its production by blocking glutaminolysis. This interdisciplinary approach combining metabolic biochemistry with MS analysis through interventional synthetic VOCs holds great potential for revolutionizing the identification of lung cancer cells and paving the way for novel cytological examination techniques.

Characteristic volatile compounds contributed to aroma of braised pork and their precursor sources

The characteristic aroma compounds of traditional braised pork were investigated by gas chromatography–mass spectrometry−olfactometry (GC–MS–O), odor-activity values, and aroma recombination and omission experiments. A total of 56 volatile compounds were detected by GC–MS, among which hexanal, octanal, nonanal, (E)-2-octenal, 2,3-octanedione, 1-octen-3-ol, 2-pentylfuran, methanethiol, and dimethyl trisulfide were identified as the key aroma compounds by molecular sensory science. Partial least squares regression analysis indicated that some aroma compounds significantly contributed to fatty (hexanal, heptanal, 2-pentylfuran, nonanal, and (E)-2-octenal), meaty (methanethiol, dimethyl disulfide, dimethyl trisulfide, and octanal), sauce-like flavor (3-hydroxy-2-butanone and 2-furfural), and sweet, caramel (2,3-octanedione, 1-octen-3-ol). Lean meat produced more aldehydes, alcohols, ketones, and sulfur-containing compounds than subcutaneous fat. The seasonings (saccharose, cooking wine, and soy sauce) facilitated the formation of ethyl L-lactate, 2-acetylfuran, 2-furfural, 5-methyl-2-furaldehyde, 2-methyl-pyrazine, and 2-acetylpyrrole. Meanwhile they reduced the content of lipid oxidation products, thereby stimulated the characteristic aroma of the Chinese traditional braised pork.

The Influence of Cooking Methods and Muscle on Beef Aroma Profile and Consumer Satisfaction: Insights from Volatile Compound Analysis

The objective of this study is to determine the effect of two distinct cooking techniques, namely roasting and stewing, on the formation of volatile compounds in various beef muscles (Semimembranosus, Biceps femoris, and Rectus femoris) and how this relates to consumer acceptance. The research employs the concept of volatile “marker” compounds to discern the influence of cooking techniques on the flavor profile of beef. Eighteen “marker compounds” were selected to represent a number of the mechanisms of formation and quantified in beef subjected to two different cooking methods. While no statistically significant differences were observed in consumer evaluations between the two cooking methods, notable disparities emerged in the consumer assessments of specific muscle cuts. Notably, the Rectus femoris muscle received the highest ratings (p < 0.05) among other evaluated muscles. The utilization of Solid-Phase Microextraction (SPME) and gas chromatography–mass spectrometry (GC-MS) methods for the analysis of volatile “marker compounds” in beef proved effective in highlighting significant differences in flavor compound classes between cooking methods, and these differed between muscles. The main effect was of the cooking method with stewed beef aroma having approximately 39× more dimethyl trisulphide, 9× more dimethyl disulphide, 7× more pentanal, 3× more hexanal, and twice as much benzaldehyde and 2-methylthiophene. Dimethyldisulphide, dimethyltrisulphide, hexanal, and heptanal, therefore, emerged as characteristic volatile compounds associated with the stewing cooking technique, suggesting their potential as markers for lipid and other oxidation reactions. This work indicates that certain lipid oxidation compounds, Strecker aldehydes, and sulfur compounds can be markers for the undesirable and/or desirable flavors of cooked beef, but that this depends on the cooking method chosen. It shows that flavor differences may be understood through the analysis of volatile flavor compounds in association with palatability and other chemical measurements.

The potential correlation between the succession of microflora and volatile flavor compounds during the production of Zhenba bacon

Microbial composition plays an important role in the quality and flavor of bacon. The aims of this study were to detect bacterial community succession using high-throughput sequencing (HTS) and volatile flavor compound changes using gas chromatography-ion mobility spectrometry (GC-IMS) during the production of Zhenba bacon. The results showed that a total of 70 volatile compounds were detected. Among them, ketones, hydrocarbons, aldehydes, esters and alcohols were the main substances in the curing and smoking stages. In addition, the fungal abundance was greater than the bacterial abundance, and there was obvious succession of the microbial community with changes in fermentation time and processing technology. The main functional bacterial genera in the curing and smoking stages were Staphylococcus, Psychrobacter and Latilactobacillus, and the main fungal genera were Fusarium and Debaryomyces. Through correlation analysis, we found that pyrrole, 2-pentanol, methyl isobutyl ketone (MIBK) and ethyl acetate (EA) were significantly correlated with Staphylococcus, Psychrobacter, Pseudomonas and Myroides (p < 0.01), and it is speculated that they contribute significantly to flavor formation. The results of this study are helpful for understanding the microbial dynamics and characteristic volatile flavor compounds in Zhenba bacon, and provide new insights into the relationship between microorganisms and flavor through potential correlations.

Effect of light treatmeat on oxidation and flavour of dry-cured Wuchang fish

Lighting conditions are an important factor affecting dry-cured products. This study investigated the effects of treatments with different light intensities (0 lx, 1000 lx, 25000 lx) and different light sources including red light, blue light, UV-light on oxidation leve and flavor change in dry-cured Wuchang fish. The results showed that dry-cured Wuchang fish exhibited an attractive brown-yellow color, the highest oxidation degree of myoglobin (Mb), the highest fat oxidation under the light conditions of 25000 lx light intensity and UV-light irradiation. This phenomenon was observed that the degree of Mb oxidation was increased, while the degree of fat oxidation was increased. At 25000 lx light intensity and UV-light irradiation, dry-cured Wuchang fish showed an ignificantly decreased fatty acid conten (especially oleic acid and linoleic acid), significantly increased characteristic volatile compound contents (22 for 25,000 lx light intensity and 27 for UV-light irradiation), which contributed to the improvement of quality stability of dry-cured Wuchang fish. Our findings provide theoretical support for the industrial application of exogenous light in dry-cured Wuchang fish.

Steam distillation process for flavor enhancement of milk coffee: Effects of condensation temperature on volatile compounds and flavor characteristics.

To enhance the flavor characteristics of milk coffee, steam distillation was applied to roasted ground coffee to obtain extracts that were then added to the hot water extract of the residue. The effects of different condensation temperatures for steam distillation on the volatile compounds of condensates and the flavor characteristics of the milk coffees prepared with each condensate were investigated. The volatile compounds were analyzed by gas chromatography/mass spectrometry, and principal component analysis (PCA) was performed on the mean peak areas of the volatiles that showed significant differences between the samples. The five types of milk coffees prepared with/without condensates were evaluated by consumer panelists using the check-all-that-apply question combined with the milk coffee flavor lexicon. The results showed that the concentration of volatile compounds tended to be higher in response to decreasing condensation temperature in steam distillation. The volatile compounds were grouped into four patterns based on their concentration in the condensates, which was affected by the volatility of the compounds and the duration of the condensation process in steam distillation. PCA clarified the characteristic volatile compounds that contribute to differences between the three condensates. The check-all-that-apply results indicated that the samples prepared with the condensates enhanced some specific coffee flavors, although acceptances for them were not enhanced. Implementing a steam distillation step in the milk coffee production process could lead to enhancing the coffee flavor strength of milk coffee products, and changing the condensation temperature for steam distillation was effective for providing different flavor characteristics of milk coffee. PRACTICAL APPLICATION: Changing the condensation temperature for steam distillation is effective in differentiating the flavor characteristics of milk coffee. Increasing the condensation temperature resulted in decreased concentrations of volatile compounds, which enhanced the milk and rich flavor. Decreasing the condensation temperature resulted in increased concentrations of volatile compounds, which provided a stronger coffee flavor to the milk coffee, possibly leading to a reduction in the use of coffee for milk coffee production. The check-all-that-apply question combined with the milk coffee flavor lexicon could effectively evaluate consumers' perceptions of the milk coffee flavor characteristics and their acceptances in a single survey.

Influence of germination and roasting on the characteristic volatile organic compounds of quinoa using sensory evaluation, E-nose, HS-GC-IMS, and HS-SPME-GC-MS

This study aimed to investigate the effects of germination and roasting on the flavor of quinoa. Firstly, the aroma of quinoa and germinated quinoa roasted under different conditions was analyzed using sensory evaluation and electronic nose (E-nose). Results showed that the best favorable aroma of quinoa and germinated quinoa was obtained when roasted at 160 °C for 15 min. Then, a total of 34 and 80 volatile organic compounds (VOCs) of quinoa and germinated quinoa roasted at 160 °C for 15 min were determined using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC–MS), respectively. Germination and roasting effectively reduced the contents of VOCs that produced undesirable flavor. Moreover, germination improved the floral aromas, while roasting mainly produced caramel, cocoa, and roasted nut aromas of quinoa. This study indicated that germination and roasting treatments might serve as promising processing methods to improve the flavor of quinoa.

Unveiling the dynamic microbial succession and metabolic characteristics during traditional fermentation of hainan shanlan rice wine

The objective of this study was to reveal the microbial succession and metabolic characteristics during traditional fermentation of Hainan Shanlan rice wine (HSRW). Correlations between core microorganisms and key metabolites were explored. Four bacterial genera (Pediococcus, Levilactobacillus, Pantoea and Limosilactobacillus) and 3 fungal genera (Saccharomyces, Rhizopus, and Saccharomycopsis) were the dominant in HSRW. Alcohols, esters and organic acids were the main metabolites in the HSRW. 2-Ethyl-1-hexanol, dimethylsilanediol, pentaethylene glycol, ethyl hexadecanoate, ethyl tetradecanoate and (E)-9-octadecenoic acid ethyl ester were identified as the characteristic volatile flavor compounds. Malic acid and lactic acid were the primary organic acids. Spearman correlation analysis revealed that Levilactobacillus and Pediococcus were the core functional microorganisms and exhibited significant associations with key metabolites. This study provides a scientific and practical foundation for elucidating the potential value of core functional microorganisms and for the development of Directed Vat Set in the industrial prodution of HSRW.

New evidence for gut-muscle axis: Lactic acid bacteria-induced gut microbiota regulates duck meat flavor

The interaction between gut microbiota and muscles through the gut-muscle axis has received increasing attention. This study attempted to address existing research gaps by investigating the effects of gut microbiota on meat flavor. Specifically, lactic acid bacteria were administered to ducks, and the results of e-nose and e-tongue showed significantly enhanced meat flavor in the treatment group. Further analyses using GC–MS revealed an increase in 6 characteristic volatile flavor compounds, including pentanal, hexanal, heptanal, 1-octen-3-ol, 2,3-octanedione, and 2-pentylfuran. Linoleic acid was identified as the key fatty acid that influences meat flavor. Metagenomic and transcriptomic results further confirmed that cecal microbiota affects the duck meat flavor by regulating the metabolic pathways of fatty acids and amino acids, especially ACACB was related to fatty acid biosynthesis and ACAT2, ALDH1A1 with fatty acid degradation. This study sheds light on a novel approach to improving the flavor of animal-derived food.

Characterization of flavor substances in cooking and seasoned cooking brown seaweeds by GC-IMS and E-nose

The flavor of algae was one of the key factors for consumer acceptance. The objective of this study was to investigate the characteristic volatile compounds in cooking and seasoned cooking edible brown seaweeds (Undaria pinnatifida and Laminaria japonica). The gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose (E-nose) analysis showed that baking resulted in significant difference in flavor of brown seaweeds. However, the overall effect of cooking was not as significant as that of the seasoning solution treatment. Additionally, brown seaweeds treated with the seasoning solution were more acceptable. Undaria pinnatifida was found to contain 72 volatile flavor compounds, while Laminaria japonica had a total of 70. This study proved the applicability of GC-IMS combined with E-nose technology to detect the changes of volatile components of brown seaweeds after processing, providing beneficial knowledge and basic theory for the deep processing of brown seaweeds.

Characteristic volatile flavors of high-oleic peanut oil and normal peanut oil

Owing to its high content of oleic acid and bioactive components, high-oleic peanut oil (HOPO) is known as a healthy edible oil. However, the characteristic volatile compounds of HOPOs remain unknown. In this study, the volatile compounds in HOPO were analyzed by gas chromatography mass spectrometry combined with headspace solid phase microextraction (HS-SPME-GC-MS) and compared with those in normal peanut oil (NPO). As results, 92 volatile compounds were identified in HOPOs and NPOs. Ten volatile compounds with significant differences between HOPO and NPO were screened out by orthogonal partial least squares discriminant analysis (OPLS-DA). In addition, a sensory evaluation indicated that the HOPO possessed a stronger sweet aroma and a lighter rancidity one month after opening the cap. This meant that the HOPO had better flavor and higher stability. This study provides a reference for the flavor improvement of HOPO.

Comparative Analysis of Characteristic Volatile Compounds in Five Types of Infant Nutrition Powders by HS-GC-IMS and GC-MS.

This study employed the headspace-gas chromatography-ion migration spectrum (HS-GC-IMS) in conjunction with the gas chromatography-mass spectrometer (GC-MS) technique for the assessment of the flavor quality of complementary food powder intended for infants and young children. A total of 62 volatile compounds were identified, including aldehydes, esters, alcohols, ketones, pyrazines, and furans, among which aldehydes were the most abundant compounds. Based on the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models, infant nutritional powder (YYB) from different manufacturers could be clearly distinguished. Among them, 2-hydroxybenzaldehyde, 1, 2-dimethoxyethane, 2-isobutyl-3-methoxypyrazine, and methyl butyrate were the four most critical differential volatiles. In addition, these differences were also manifested in changes in fatty acids. The reason for this phenomenon can be attributed to the difference in the proportion of raw materials used in nutrition powder, micronutrient content, and the packaging process. In conclusion, this study provides comprehensive information on the flavor quality of YYB, which can be used as a basis for quality control of YYB.

Influence of heating temperatures and storage on the odor of duck meat and identification of characteristic odorous smell compounds

To clarify the characteristic odor of compounds present in duck meat, especially reheating after storage, the effect of duck breast cooked at three temperatures (90 °C, 100 °C, 105 °C) and reheating after 7 days of storage was studied. Electronic nose analysis and sensory evaluation revealed a significant increase (p < 0.05) in reheated duck meat odor after 7 days of storage. The 90 °C treatment group had the heaviest odor, which increased by 12.19 % after seven days of storage. Using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), 60 volatile flavor compounds were identified across various groups. Although the volatile compounds were consistent among different groups, their relative contents varied. By combining the sensory evaluation results with the Relative Odor Activity Value (ROAV) of these flavor compounds, chemometric orthogonal partial least squares discriminant analysis (OPLS-DA) was used to identify the following 9 characteristic volatile compounds: 2-methylbutanal, pentanal, octanal, heptanal, hexanal, (E)-2-octenal, (E)-2-nonenal, and 2-pentyl furan

Dynamic changes of microbiota and metabolite of traditional Hainan dregs vinegar during fermentation based on metagenomics and metabolomics

Hainan dregs vinegar (HNDV) is a traditional fermented food in China that is renowned for its unique flavor. HNDV is one of the most popular vinegars in Southeast Asia. However, research on the microorganisms and characteristic metabolites specific to HNDV is lacking. This study investigated the changes in microbial succession, volatile flavor compounds and characteristic non-volatile flavor compounds during HNDV fermentation based on metagenomics and metabolomics.The predominant microbial genera were Lactococcus, Limosilactobacillus, Lactiplantibacillus, and Saccharomyces. Unlike traditional vinegar, l-lactic acid was identified as the primary organic acid in HNDV. Noteworthy flavor compounds specific to HNDV included 3-methylthiopropanol and dl-phenylalanine. Significant associations were observed between six predominant microorganisms and six characteristic volatile flavor compounds, as well as seven characteristic non-volatile flavor compounds. The present results contribute to the development of starter cultures and the enhancement of HNDV quality.

Study on the dynamic change of volatile components of white tea in the pile-up processing based on sensory evaluation and ATD-GC–MS Technology

The pile-up processing has a great impact on the flavor of white tea. To investigate the effects of the volatile accumulation of white tea with different piling thickness treatments, tea leaves from different thickness treatments were subjected to sensory quantitative description analysis and ATD-GC–MS detection in this study. As a result, 122 volatile components were identified from white tea with different treatments. A total of 8 key compounds, including isovaleraldehyde, isobutyraldehyde, 2-methyl-butanal, 1-octene-3-ol, linalool, pentanoic acid, hexanal and 1-hexanol were screened out using multivariate statistical analysis, which were characteristic components of grassy, floral-fruity, pekoe aroma and sweet flavors. The results of the selected key characteristic volatile compounds were consistent with the sensory quantitative description. The aroma of mid-pile dried tea (MD) was exhibited a harmonious and pleasant overall flavor. This study provides a novel insight into the accumulation of volatile during the withering step of white tea production.

Effects of Monascus purpureus on ripe Pu-erh tea in different fermentation methods and identification of characteristic volatile compounds

The present study aimed to explore the key volatile compounds (VCs) that lead to the formation of characteristic flavors in ripe Pu-erh tea (RIPT) fermented by Monascus purpureus (M. purpureus). Headspace solid-phase microextraction coupled with gas chromatography/mass spectrometry (HS-SPME-GC–MS), orthogonal partial least square-discriminant analysis (OPLS-DA) were employed for a comprehensive analysis of the VCs present in RIPT fermented via different methods and were further identified by odor activity value (OAV). The VCs 1,2-dimethoxybenzene, 1,2,3-trimethoxybenzene, (E)-linalool oxide (pyranoid), methyl salicylate, linalool, β-ionone, β-damascenone were the key characteristic VCs of RIPT fermented by M. purpureus. OAV and Gas chromatography–olfactometry (GC-O) further indicated that β-damascenone was the highest contribution VCs to the characteristic flavor of RIPT fermented by M. purpureus. This study reveals the specificities and contributions of VCs present in RIPT under different fermentation methods, thus providing new insights into the influence of microorganisms on RIPT flavor.

Enhancement of fermented sausage quality driven by mixed starter cultures: Elucidating the perspective of flavor profile and microbial communities

The metabolic activities of microorganisms play a crucial role in the quality development of fermented sausage. This study investigated the effect of inoculation with different combinations of starter cultures (Lactiplantibacillus plantarum YR07, Latilactobacillus sakei L.48, Staphylococcus xylosus S.14, and Mammaliicoccus sciuri S.18) on the quality of sausages. Inoculation with mixed starter cultures promoted protein degradation to generate amino acids and the conversion to volatile compounds, which enhanced the flavor development in fermented sausages. The bacterial community analyses demonstrated that the inoculation of mixed starter cultures could inhibit the growth of spoilage and pathogenic bacteria, thereby reducing the total content of biogenic amines. The correlation analysis between the core bacteria and characteristic volatile compounds revealed that fermented sausages inoculated with Lactobacillus and coagulase negative staphylococci exhibited significant positive correlations with the majority of key characteristic volatile compounds. In four treatments, inoculation with L. plantarum YR07 and M. sciuri S.18 greatly promoted the formation of characteristic volatile compounds (3-hydroxy-2-butanone, hexanal, and 1- octen-3ol). Therefore, the combined inoculation of L. plantarum YR07 and M. sciuri S.18 is promising to enhance fermented sausage's flavor profile and safety.

Multi-omics revealed the formation mechanism of characteristic volatiles in Tibetan yak cheese induced by different altitudes

The variation in volatiles, bacteria and metabolites of Tibetan yak cheese (TYC) from different altitudes were characterized with multi-omics to reveal the formation mechanism of characteristic volatile compounds (C-VOCs) in TYC induced by altitudes. 22C-VOCs (odor activity value, OAV > 1) were identified in TYCs, and hexanal, dodecanol, 2,3-butanediol, butyl isobutyate, etc., C-VOCs were confirmed induced by altitude. Lactobacillus, Kocuria, etc., bacteria and benzyl thiocyanate, trehalose, sarcosine, etc., metabolites were screened as the variable bacteria and metabolites for TYCs regulated by altitude, respectively. Pediococcus and carbonhydrates maybe the main contributors for the formation of C-VOCs in TYCs induced by altitudes. The formation of dodecanol, 2,3-butanediol and hexanal maybe derived from sarcosine and EPA, and the generation of butyl isobutyrates maybe originated from 1,6-DP-fructose and threonic acid facilitating by Pediococcus. This research will help us gain insight into the contribution of altitude to the formation of volatiles in TYCs.

Sensing nature's alarm: SnO2/MXene gas sensor unveils methyl jasmonate signatures of plant insect stress.

The incorporation of artificial intelligence into agriculture presents challenges, particularly due to hardware limitations, especially in sensors. Currently, pest detection relies heavily on manual scouting by humans. Therefore, the objective of this study is to create a chemoresistive sensor that enables early identification of the characteristic volatile compound, viz., methyl jasmonate, released during pest infestations. Given the lower reactivity of esters, we have fine-tuned a composite consisting of SnO2 nanoparticles and 2D-MXene sheets to enhance adsorption and selective oxidation, resulting in heightened sensitivity. The optimized composite demonstrated a notable response even at concentrations as low as 120 ppb, successfully confirming pest infestations in tomato crops.

Maillard Reaction Process and Characteristic Volatile Compounds Formed During Secondary Thermal Degradation Monitored via the Change of Fluorescent Compounds in the Reaction of Xylose-Corn Protein Hydrolysate.

Until now, no effective method has been found to monitor the Maillard reaction process for complex protein hydrolysates. Dynamic changes in the concentration of α-dicarbonyl compounds, fluorescence intensity, and browning degree were investigated during the Maillard reaction of corn protein hydrolysates. When the fluorescence intensity reached the peak, deoxyosones would continue to be increased by ARP's degradation. However, the reaction node with the highest fluorescence intensity coincided with the turning point of the browning reaction, and the subsequent browning rate remarkably increased. Therefore, the change in fluorescence intensity could be used to monitor the degradation of ARP and the formation of browning melanoidin at different stages of the Maillard reaction of complex systems, thus effectively indicating the process of the Maillard reaction. When Maillard reaction intermediates (MRIs) with maximum fluorescent compounds were heated, the most abundant pyrazines were subsequently achieved. However, furan compounds would be progressively increased during the thermal process of MRIs with continuously enhanced browning.