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Different origins and qualities can lead to differences in the taste and aroma of tea; however, the impacts of origin and quality on the taste and aroma characteristics of Wuyi rock tea and Huizhou rock tea have rarely been studied. In this study, high-performance liquid chromatography (HPLC), gas chromatography–mass spectrometry (GC–MS), and sensory evaluation methods were used to compare the quality components of Wuyi rock tea and Huizhou rock tea. The sensory evaluation showed that they each have their own characteristics, but the overall acceptability of Wuyi rock tea is ahead of Huizhou rock tea (p < 0.01). Biochemical experiments showed that HT was the highest in water leachables, about 43.12%; WT was the highest in tea polyphenols, about 14.91%; WR was the highest in free amino acids, about 3.38%; and the six rock teas had different health benefits. High-performance liquid chromatography showed that the theanine contents of WS and WR were 0.183% and 0.103%, respectively, which were much higher than those of other varieties. The OPLS-DA model predicted the factors that caused their different tastes, in order of contribution: CG > ECG > caffeine > EGCG > theanine. Ten volatile substances with OAV ≥ 1 and VIP > 1 were also found, indicating that they contributed greatly to the aroma characteristics, especially hexanoic acid, hexyl ester, and benzyl nitrile. The results of the correlation analysis showed that theanine was significantly correlated with taste (p < 0.05), and hexanoic acid, hexyl ester, and benzyl nitrile were significantly correlated with smell (p < 0.05). Substances such as theanine, hexanoic acid, hexyl ester, and benzyl nitrile give them their unique characteristics. Analysis of the differences in the quality components of the six rock teas can provide reference value for the cultivation and processing of rock teas. [ABSTRACT FROM AUTHOR]

Cigar tobacco leaves exhibited distinct regional characteristics, and aroma compounds were the key substances determining the different style features of cigars. However, the differences in aroma characteristics and the mechanisms of key aroma compound synthesis have not been fully elucidated. This study collected filler tobacco leaves (FTLs) from 5 representative domestic and international production regions. Gas chromatography-mass spectrometry (GC-MS) identified aroma compounds, an aroma wheel was established based on odor activity values (OAV), and principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) revealed major differences. Synthesis pathways of key differential components were further explored using the Kyoto Encyclopedia of Genes and Genomes (KEGG). In this study, 56 aroma compounds were identified in FTLs. Imported-FTLs (IMP-FTLs) contained higher levels of ketones and esters, along with moderate nicotine content, and exhibited a more noticeable sour and woody aroma. In contrast, Domestic-FTLs (DOM-FTLs) had a greater distribution of aldehydes, phenols, and neophytadiene, presenting a more prominent bean, burnt-sweet, and floral aroma. Nine compounds, including sclareol, 5-methylfurfural, and (E)-5-isopropyl-8-methylnona-6,8-dien-2-one, were identified as key differential components, and their synthesis primarily involves pathways such as phenylalanine metabolism and carotenoid biosynthesis. These findings provided a novel perspective on the targeted enhancement of key aroma compounds, which was significant for improving the aroma quality of filler tobacco leaves. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the key flavor characteristics and the influence of oxidation degree of oil on warmed-over flavor of pre-prepared steamed pork with preserved vegetable. The volatile flavor compounds and taste indexes of different brands of pre-prepared steamed pork with preserved vegetable were quantitatively detected by headspace-solid phase microextraction-gas chromatography-mass spectrometry and electronic tongue. The key flavor factors of pre-prepared steamed pork with preserved vegetable were screened and analyzed by odor activity value (OAV) and principal component analysis. Acid value, peroxide value and TBA value were used to analyze the oxidation degree of oil and warmed-over flavor of different brands of pre-prepared steamed pork with preserved vegetable. Results showed that a total of 85 volatile compounds were identified from 7 kinds of pre-prepared steamed pork with preserved vegetable, including 16 alkanes, 19 terpenes, 7 alcohols, 22 aldehydes, 3 ketones, 13 esters, 3 phenols and 2 others. A total of 23 key volatile compounds were screened by OAV, and the substances with OAV>10 were 1-octene-3-ol, hexanal, heptanal, octanal, nonanal, (E,E)-2,4-nonadienal, capric aldehyde, (E)-2-decenal, (E,E)-2,4-decenal and 1-octene-3-ketone, which were the key flavor substances for pre-prepared steamed pork with preserved vegetable. The results of electronic tongue and overripe taste evaluation showed that the taste of 7 kinds of pre-prepared steamed pork with preserved vegetable were mainly salty, umami and aftertaste. Its overripe taste mainly presented linseed oil taste and rancidity taste. The oil oxidation indexes of 7 kinds of pre-prepared steamed pork with preserved vegetable were higher and the differences were significant (P

In order to study the key flavor characteristics and the influence of oxidation degree of oil on warmed-over flavor of pre-prepared steamed pork with preserved vegetable. The volatile flavor compounds and taste indexes of different brands of pre-prepared steamed pork with preserved vegetable were quantitatively detected by headspace-solid phase micro- extraction-gas chromatography-mass spectrometry and electronic tongue. The key flavor factors of pre-prepared steamed pork with preserved vegetable were screened and analyzed by odor activity value (OAV) and principal component analysis. Acid value, peroxide value and TBA value were used to analyze the oxidation degree of oil and warmed-over flavor of different brands of pre-prepared steamed pork with preserved vegetable. Results showed that a total of 85 volatile compounds were identified from 7 kinds of pre-prepared steamed pork with preserved vegetable, including 16 alkanes, 19 terpenes, 7 alcohols, 22 aldehydes, 3 ketones, 13 esters, 3 phenols and 2 others. A total of 23 key volatile compounds were screened by OAV, and the substances with OAV>10 were 1-octene-3-ol, hexanal, heptanal, octanal, nonanal, (E,E)-2,4- nonadienal, capric aldehyde, (E)-2-decenal, (E,E)-2,4-decenal and 1-octene-3-ketone, which were the key flavor substances for pre-prepared steamed pork with preserved vegetable. The results of electronic tongue and overripe taste evaluation showed that the taste of 7 kinds of pre-prepared steamed pork with preserved vegetable were mainly salty, umami and aftertaste. Its overripe taste mainly presented linseed oil taste and rancidity taste. The oil oxidation indexes of 7 kinds of pre-prepared steamed pork with preserved vegetable were higher and the differences were significant (P<0.05). The correlation analysis showed that the main factors that produce warmed-over flavor were (E)-2-decenal, 2-heptanone, nonylaldehyde, 1-octene-3-ketone, (E,E)-2,4-decenal, hexal, pentaldehyde, heptanal, (E)-2-heptenal and octanal, which were positively correlated with acid value, peroxide value and TBA value. In summary, the key flavor factors of the 7 kinds of pre-prepared steamed pork with preserved vegetable were related to overcooked taste, and it was speculated that the overcooked taste of pre-prepared steamed pork with preserved vegetable was related to the higher oxidation degree of oil. The key flavor factors, electronic tongue and overripe taste evaluation indexes obtained in this study provide the basis for the establishment of flavor quality system and overripe taste control of pre-prepared steamed pork with preserved vegetable. [ABSTRACT FROM AUTHOR]

Aroma in food plays an important role in food perception and acceptance, which depends on various mixtures of volatile organic compounds (VOCs). Moreover, VOCs are of great significance for aroma identification. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS) technology was used to determine the VOCs in 10 pear syrups. A total of 127 VOCs were quantitatively determined, including 9 common VOCs and 46 characteristic VOCs of 10 pear syrups. The pear syrups were divided into three categories by cluster analysis, and thirty-eight differential VOCs were obtained using orthogonal partial least squares discrimination analysis (OPLS-DA) and fourteen key VOCs were selected by odor activity value (OAV). It was revealed that the key and common aroma components of pear syrups were butanoic acid, methyl ester, 2-methyl-, methyl ester and Hexanoic acid, and ethyl ester. The characteristic and differential VOCs were 10-Undecen-1-ol, Hexadecanal, n-Propylacetate, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1S,2R,5S)-, Methional, Disulfide, dimethyl, 8-Nonenoic acid, ethyl ester, Naphthalene, 1,2-dihydro-1,1,6-trimethyl-, 3H-Purin-6-amine, N,N,3-trimethyl-, 2-Octanol,2,6-dimethyl-, Furyl hydroxymethyl ketone, Heptane, 2,2,4,6,6-pentamethyl-, and Butanoic acid,2-methyl-,methyl ester. The above results showed that different pear syrups had rich diversity in aroma compounds, with some components being shared among them while others are exclusive to specific syrups. [ABSTRACT FROM AUTHOR]

Introduction: The cheese microbiota is very complex and is made up of technologically-relevant, spoilage, opportunistic and pathogenic microorganisms. Among them lactic acid bacteria and yeasts are the main ones. One of the most interesting dairy yeasts is Kluyveromyces marxianus because of its technological properties including the ability to produce aroma compounds. Methods: This study investigated the contribution of Kluyveromyces marxianus to the gross composition and aroma profile of cow cheeses. Experimental cheeses were prepared by inoculating a co-culture of K. marxianus FM09 and a commercial strain of Lacticaseibacillus casei and compared with cheeses obtained with only L. casei. The gross composition was determined by a FoodScan™ 2 Dairy Analyser, and free amino acids were evaluated at 507 nm after reaction with Cd-ninhydrin. The volatile organic compounds were extracted by head-space solid phase micro-extraction and analyzed by gas chromatography-mass spectrometry coupled with odor activity values. qRT-PCR was applied to determine the expression of genes involved in esters synthesis and degradation. Results: The inoculation of K. marxianus induced an increase of pH and a reduction of protein content of cheeses, in agreement with the stronger proteolysis detected in these cheeses. K. marxianus influenced the content of aroma compounds both quantitatively and qualitatively. In particular, an increase of higher alcohols, esters and organic acids was observed. Moreover, 12 compounds were detected only in cheeses obtained with the co-culture. These differences were in agreement with the odor activity values (OAV). In fact, only 11 compounds showed OAV > 1 in cheeses obtained with the commercial strain, and 24 in those obtained with the co-culture. The qPCR analysis revealed an over expression of ATF1, EAT1, and IAH1 genes. Conclusion: Kluyveromyces marxianus could act as an important auxiliary starter for cheese production through the development and diversification of compounds related to flavor in short-aged cow cheeses. [ABSTRACT FROM AUTHOR]

Summary: Four different extraction methods were used to extract aroma compounds from flour. It was found that dynamic headspace sampling (DHS) was a better method for extracting aroma‐active compounds in flour. Hexanal, decanal, butanoic acid, 2,3‐pentanedione, 2‐acetyl‐1‐pyrrolinoline, and 3‐octen‐2‐one were found to be the important aroma‐active compounds in flour by olfaction (O) in two‐dimensional gas chromatography–olfactometry–mass spectrometry (GC×GC‐O‐MS). Dynamic headspace dilution analysis (DHDA), odour activity value (OAV), recombination and omission experiment further verified that these compounds can roughly simulate the overall aroma profile of flour. In this study, we determined the aroma‐active compounds in flour by molecular sensory science to improve the sensory preference of flour and enhance the quality of flour aroma, which will provide analytical ideas for future research on flour aroma and improve the production process. [ABSTRACT FROM AUTHOR]

Cigar tobacco leaves exhibited distinct regional characteristics, and aroma compounds were the key substances determining the different style features of cigars. However, the differences in aroma characteristics and the mechanisms of key aroma compound synthesis have not been fully elucidated. This study collected filler tobacco leaves (FTLs) from 5 representative domestic and international production regions. Gas chromatography-mass spectrometry (GC-MS) identified aroma compounds, an aroma wheel was established based on odor activity values (OAV), and principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) revealed major differences. Synthesis pathways of key differential components were further explored using the Kyoto Encyclopedia of Genes and Genomes (KEGG). In this study, 56 aroma compounds were identified in FTLs. Imported-FTLs (IMP-FTLs) contained higher levels of ketones and esters, along with moderate nicotine content, and exhibited a more noticeable sour and woody aroma. In contrast, Domestic-FTLs (DOM-FTLs) had a greater distribution of aldehydes, phenols, and neophytadiene, presenting a more prominent bean, burnt-sweet, and floral aroma. Nine compounds, including sclareol, 5-methylfurfural, and (E)-5-isopropyl-8-methylnona-6,8-dien-2-one, were identified as key differential components, and their synthesis primarily involves pathways such as phenylalanine metabolism and carotenoid biosynthesis. These findings provided a novel perspective on the targeted enhancement of key aroma compounds, which was significant for improving the aroma quality of filler tobacco leaves.

The term "recurrent constellations of embryonic malformations" (RCEM) is used to describe a number of multiple malformation associations that affect three or more body structures. The causes of these disorders are currently unknown, and no diagnostic marker has been identified. Consequently, providing a definitive diagnosis in suspected individuals is challenging. In this study, genome-wide DNA methylation analysis was conducted on DNA samples obtained from the peripheral blood of 53 individuals with RCEM characterized by clinical features recognized as VACTERL and/or oculoauriculovertebral spectrum association. We identified a common DNA methylation episignature in 40 out of the 53 individuals. Subsequently, a sensitive and specific binary classifier was developed based on the DNA methylation episignature. This classifier can facilitate the use of RCEM episignature as a diagnostic biomarker in a clinical setting. The study also investigated the functional correlation of RCEM DNA methylation relative to other genetic disorders with known episignatures, highlighting the common genomic regulatory pathways involved in the pathophysiology of RCEM. This study identified a common DNA methylation episignature in 40/53 individuals with recurrent constellations of embryonic malformations (RCEM). This episignature can serve as a diagnostic biomarker, enhancing diagnosis accuracy. Additionally, the study revealed shared genomic pathways between RCEM and other genetic disorders, advancing our understanding of their underlying mechanisms. [ABSTRACT FROM AUTHOR]

IntroductionThe cheese microbiota is very complex and is made up of technologically-relevant, spoilage, opportunistic and pathogenic microorganisms. Among them lactic acid bacteria and yeasts are the main ones. One of the most interesting dairy yeasts is Kluyveromyces marxianus because of its technological properties including the ability to produce aroma compounds.MethodsThis study investigated the contribution of Kluyveromyces marxianus to the gross composition and aroma profile of cow cheeses. Experimental cheeses were prepared by inoculating a co-culture of K. marxianus FM09 and a commercial strain of Lacticaseibacillus casei and compared with cheeses obtained with only L. casei. The gross composition was determined by a FoodScan™ 2 Dairy Analyser, and free amino acids were evaluated at 507 nm after reaction with Cd-ninhydrin. The volatile organic compounds were extracted by head-space solid phase micro-extraction and analyzed by gas chromatography–mass spectrometry coupled with odor activity values. qRT-PCR was applied to determine the expression of genes involved in esters synthesis and degradation.ResultsThe inoculation of K. marxianus induced an increase of pH and a reduction of protein content of cheeses, in agreement with the stronger proteolysis detected in these cheeses. K. marxianus influenced the content of aroma compounds both quantitatively and qualitatively. In particular, an increase of higher alcohols, esters and organic acids was observed. Moreover, 12 compounds were detected only in cheeses obtained with the co-culture. These differences were in agreement with the odor activity values (OAV). In fact, only 11 compounds showed OAV > 1 in cheeses obtained with the commercial strain, and 24 in those obtained with the co-culture. The qPCR analysis revealed an over expression of ATF1, EAT1, and IAH1 genes.ConclusionKluyveromyces marxianus could act as an important auxiliary starter for cheese production through the development and diversification of compounds related to flavor in short-aged cow cheeses.

Different origins and qualities can lead to differences in the taste and aroma of tea; however, the impacts of origin and quality on the taste and aroma characteristics of Wuyi rock tea and Huizhou rock tea have rarely been studied. In this study, high-performance liquid chromatography (HPLC), gas chromatography–mass spectrometry (GC–MS), and sensory evaluation methods were used to compare the quality components of Wuyi rock tea and Huizhou rock tea. The sensory evaluation showed that they each have their own characteristics, but the overall acceptability of Wuyi rock tea is ahead of Huizhou rock tea (p < 0.01). Biochemical experiments showed that HT was the highest in water leachables, about 43.12%; WT was the highest in tea polyphenols, about 14.91%; WR was the highest in free amino acids, about 3.38%; and the six rock teas had different health benefits. High-performance liquid chromatography showed that the theanine contents of WS and WR were 0.183% and 0.103%, respectively, which were much higher than those of other varieties. The OPLS-DA model predicted the factors that caused their different tastes, in order of contribution: CG > ECG > caffeine > EGCG > theanine. Ten volatile substances with OAV ≥ 1 and VIP > 1 were also found, indicating that they contributed greatly to the aroma characteristics, especially hexanoic acid, hexyl ester, and benzyl nitrile. The results of the correlation analysis showed that theanine was significantly correlated with taste (p < 0.05), and hexanoic acid, hexyl ester, and benzyl nitrile were significantly correlated with smell (p < 0.05). Substances such as theanine, hexanoic acid, hexyl ester, and benzyl nitrile give them their unique characteristics. Analysis of the differences in the quality components of the six rock teas can provide reference value for the cultivation and processing of rock teas.

To investigate the impact of various cooking methods on the volatile aroma compounds of button mushroom, gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose) were utilized for aroma analysis. The results indicated that the E-nose was able to effectively distinguish between the samples prepared using different cooking methods. In the raw, steamed, boiled and baked samples, 37, 23, 33 and 35 volatiles were detected, respectively. The roasting process significantly contributed to the production of flavor compounds, giving button mushroom its distinctive flavor. Sixteen differential aromas were identified based on the p-value and VIP value. Additionally, the cluster analysis of differential aroma substances revealed a stronger odor similarity between the steamed and raw groups, consistent with the results of the OPLS-DA analysis of overall aroma components. Seven key aromas were identified through OAV analysis and omission experiments. In addition, 1-octen-3-one was identified as the main aroma component of cooked button mushroom. The findings of the study can be valuable for enhancing the flavor of cooked button mushroom. [ABSTRACT FROM AUTHOR]

To investigate the effect of ultrasound treatment on the flavor profile of beef during postmortem aging, a comprehensive analysis of beef flavor was conducted at 0, 7, and 12 d of aging using sensory evaluation and electronic nose. Furthermore, the key volatile flavor compounds were identified using gas chromatography-mass spectrometry (GC–MS), and the odor activity value (OAV) was further evaluated. In addition, the primary pathway involved in flavor formation during beef aging after ultrasound treatment was explored. The results indicated that ultrasound enhanced the flavor profile of beef during postmortem aging by modifying the OAV of hexanal, heptanal, octanal, nonanal, decanal, (Z)-2-nonenal, dodecanal, pentanal, 1-octen-3-ol, octanoic acid, and 2-pentylfuran. Lipid oxidation was a crucial pathway through which ultrasound promoted the generation of volatile flavor compounds in beef, confirmed by the improved oxidation level of fatty acids, particularly monounsaturated ones. The study indicates that ultrasound technology can be regarded as an effective method for enhancing the beef flavor profile during postmortem aging.

This paper investigated the compositional changes of Rosa roxburghii Tratt. fruit vinegar during fermentation. By using Rosa roxburghii Tratt. as raw material and using the whole liquid fermentation technique, fruit vinegar was prepared by fermenting alcoholic and acetic acids simultaneously. The physicochemical properties of the fermentation process were dynamically monitored. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and the odor activity value (OAV) were utilized to analyze volatile flavor components. As fermentation proceeded, soluble solids, pH, total sugars, and reduced sugars decreased, while total acid and VC contents increased. From the original juice to the end of acetic acid fermentation, the total acid and VC contents ranged from 1.86 g/100 mL and 956.82 mg/100 mL to 6.79 g/100 mL and 1275.88 mg/100 mL. Oxalic acid, quinic acid, pyruvic acid, ascorbic acid, lactic acid, acetic acid, and fumaric acid showed varying degrees of increasing (P

Aroma in food plays an important role in food perception and acceptance, which depends on various mixtures of volatile organic compounds (VOCs). Moreover, VOCs are of great significance for aroma identification. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS) technology was used to determine the VOCs in 10 pear syrups. A total of 127 VOCs were quantitatively determined, including 9 common VOCs and 46 characteristic VOCs of 10 pear syrups. The pear syrups were divided into three categories by cluster analysis, and thirty-eight differential VOCs were obtained using orthogonal partial least squares discrimination analysis (OPLS-DA) and fourteen key VOCs were selected by odor activity value (OAV). It was revealed that the key and common aroma components of pear syrups were butanoic acid, methyl ester, 2-methyl-, methyl ester and Hexanoic acid, and ethyl ester. The characteristic and differential VOCs were 10-Undecen-1-ol, Hexadecanal, n-Propylacetate, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1S,2R,5S)-, Methional, Disulfide, dimethyl, 8-Nonenoic acid, ethyl ester, Naphthalene, 1,2-dihydro-1,1,6-trimethyl-, 3H-Purin-6-amine, N,N,3-trimethyl-, 2-Octanol,2,6-dimethyl-, Furyl hydroxymethyl ketone, Heptane, 2,2,4,6,6-pentamethyl-, and Butanoic acid,2-methyl-,methyl ester. The above results showed that different pear syrups had rich diversity in aroma compounds, with some components being shared among them while others are exclusive to specific syrups.

To attain the differences in the flavor profile of Douchi, the key aroma-active compounds of three types of Douchi were investigated. The “Sauce-like”, “Smoky”, “Nutty”, “Roast”, “Caramel”, and “Flower” of Douchi were favored by customers. Further, a total of 179 volatile compounds were identified using HS-SPME-GC-MS, and 29 aroma compounds were detected using GC-O-MS. Based on the quantification, 9, 13, and 10 compounds were regarded as aroma-active compounds in Yangjiang Douchi (YJ), Pingjiang Douchi (PJ), and Liuyang Douchi (LY), respectively. Moreover, the mixture of these aroma-active compounds successfully simulated the main aromas of PJ, LY, and YJ. And omission experiments confirmed that guaiacol was the key aroma compound for LY, benzene acetaldehyde, dimethyl trisulfide, and 2-acetyl pyrrole were important for YJ, benzene acetaldehyde and 3,5-diethyl-2-methyl pyrazine notably contributed to key aroma of PJ.

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectroscopy (HS–SPME–GC–MS) and Odor Activity Value (OAV) analysis were used to characterize the aroma components of Chuanhong congou black tea. The key aroma compounds were screened by combining Principal Component Analysis (PCA), Orthogonal Partial Least Squares Discrimination Analysis (OPLS-DA) model, and Variable Importance Projection (VIP). The perceived interactions among the key aroma compounds in the tea were analyzed using Feller summation model and S-curve. Thus, 89 volatile aroma compounds were identified in the samples. Thirty key aroma compounds (OAV > 1) were screened by OAV, PCA (R2Xcum = 0.941, Q2cum = 0.897), and OPLS-DA (R2cum > 0.9, Q2cum > 0.9). Results showed a good model fit and more effective clustering of the samples. Finally, eight key aroma compounds were screened, which included trans-2-Hexenal, 2-hexenal, linalool, hexanal, phenylacetaldehyde, methyl salicylate, benzaldehyde, and (E)-linalool oxide (furan type). The perceived interactive relationships among the key aroma substances showed that 12 of the 15 groups of binary compounds had masking effects and 3 groups had additive effects. The results would serve as a reference for improving the quality of Chuanhong congou black tea. [ABSTRACT FROM AUTHOR]

The research investigates the variations in floral scent composition among different species and developmental stages of Iris plants: Iris uniflora, Iris typhifolia, and Iris sanguinea. The study analyzes the fragrance components by utilizing electronic nose technology in tandem with headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Principal component analysis (PCA), linear discriminant analysis (LDA), and loading analysis are applied to discern whether floral scents of the same Iris species at distinct stages could be differentiated. The results show that the electronic nose significantly distinguishes the aromas from different stages and that there are differences in aroma composition. Gas Chromatography-Mass Spectrometry confirms significant differences in volatile components regarding the three Iris species, with common compounds like alcohols, aromatics, and aldehydes present throughout stages. Notably, nonyl aldehyde, capric aldehyde, 2,4-di-tert-butylphenol, and n-heptadecane are consistently found. Cluster analysis reveals a grouping of decay stage samples of Iris typhifolia and Iris sanguinea due to terpene and ester abundance. Nonyl aldehyde significantly contributes to the aroma profiles of all species, owing to its high odor activity value. The significant content of volatile compounds in these Iris varieties suggests economic and medicinal potential beyond ornamental value, providing references for the development of Iris-scented products, aromatherapy, and the extraction of pharmacologically active substances from Iris. [ABSTRACT FROM AUTHOR]

Reducing and controlling industrial odor fluxes requires a complete characterization of emissions. In particular, knowing the chemical nature, in terms of nature and concentration of pollutants, and evaluating the odor potential of odorous emissions are necessary to understand and manage industrial odorous fluxes by choosing the correct abatement system. Due to the complexity of the odorous matrix, a combination of different techniques appears the best choice to obtain a complete characterization of industrial fluxes. Dynamic olfactometry is the only standardized technique to measure odor concentration (C od), that exploits the human nose as a sensor to determine the concentration at which odor can be perceived. Regarding chemical information (the nature and the quantification of pollutants), the principal technique is Gas chromatography coupled with Mass Spectrometry (GC–MS). In parallel, other instruments (specific or non-specific instruments) or additional GC detectors are used in the odor characterization context. Every technique has advantages and drawbacks; therefore, the use of complementary procedures and the combination of different analytical instrumentations appears fundamental to obtain as much information as possible about odor. This chapter aims to illustrate all these techniques applied to odor characterization, the potentiality and the limits of their application. [ABSTRACT FROM AUTHOR]

Cigars have unique aroma and style characteristics. In order to clarify the differences of aroma components between domestic and imported cigars and the material basis of the stylistic characteristics of different cigars, gas chromatography-mass spectrometry (GC-MS) and sensory evaluation were used to compare and analyze the aroma components in the mainstream smoke of four domestic cigars and two imported cigars. The GC-MS results showed that a total of 97 aroma components were measured in the smoke of the six cigars, and the types of aroma components were similar, but there were differences in their contents. In comparison with those of domestic cigars, imported cigars had suitable nicotine content, and higher contents of phytol, neophytadiene, 3-methylpentanoic acid, and (+)-δ-cadinene. To further explore the differences in the aroma components of the six cigars, GC-MS data combined with chemometrics were used to screen out 14 key aroma components based on P-value (P) 1, and Aroma Activity Values (OAV) > 1. The key aroma components of each cigar were obtained, Snow Dream No. 5: cedrol; Wangguan Guocui: 6-methyl-5-hepten-2-one, pyridine, 2-ethyl-6-methylpyrazine; General Achileus No. 3: p-cresol, 2-methylbutyraldehyde, methyl cyclopentenolone; Montecristo No. 4: cedrol, 2-methylbutyraldehyde, guaiacol, 4-vinylguaiacol, methyl cyclopentenolone; Romeo y Julieta Wide Churchills: cedrol, 2,6-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-heptanone, phenethyl alcohol; Great Wall No. 2: p-cresol, phenethyl alcohol, geranylacetone, methyl cyclopentenolone, dihydroactinidiolide. The odor descriptors of these compounds were consistent with the aroma profiles that were prominent in the senses of each cigar. This experiment initially explored the differences in aroma composition and style characteristics of cigars and provided data to support the quality improvement of domestic cigars.

Objective: To clarify the differences of volatile aroma substances among rice, rice and cooked rice under acidic conditions, and to provide data support for the analysis of volatile flavor differences in the distillation process of nong-flavor liquor. Methods: Headspace solid phase microextraction-comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (HS-SPME-GC-TOFMS) was used to identify volatile aroma compounds in raw rice (broken rice flour) and cooked rice (cooked rice, cooked rice with acid). The differences of volatile flavor compounds between samples were analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA) and aroma activity value (OAV). Results: A total of 98 volatile flavor substances were identified in broken rice flour, rice and rice with acid, which were 65,55 and 68 volatile substances, respectively, of which 31 were common substances. The number and content of substances were mainly alcohols, aldehydes, esters and ketones. Based on the content of volatile flavor compounds in the three samples, OPLS-DA analysis was carried out. The results showed that there were 54 different substances with VIP > 1 in the three samples. Among them, there were 24 substances such as 2-heptanone, 2,3-octane- dione and dihydro-5-pentyl-2 (3H)-Furanone in broken rice flour, 6 substances such as 3-thiophenecarboxaldehyde, 2, 3-pentanedione and 2,6,6-trimethyl-2-cyclohexene-1,4-dione in rice, and furfuryl alcohol, furfural and thearone in rice with acid. Isovaleric acid and other 24 kinds. OAV analysis showed that ethyl caproate had higher OAV values in the three samples, and the OAV of 2-acetyl-1-pyrroline in broken rice flour and rice was > 10. The highest OAV value in acid-added rice was ethyl caproate, and 2-acetyl-1-pyrroline was not detected in acid-added rice. The OAV values of 1-octene-3-ol, nonanal, ethyl caproate and other substances increased to varying degrees compared with the substances with OAV > 0.1 in rice. These substances with OAV > 0.1 could assist the overall aroma presentation, which was one of the reasons for the difference in aroma between rice and rice with acid. Conclusion: HS-SPME-GC-TOFMS combined with OPLS-DA and OAV were used to explore the differences of volatile compounds between raw rice, cooked rice and cooked rice under acidic conditions, so as to provide data reference for clarifying the effect of nong-flavor liquor on the extraction of volatile flavor substances in rice during 'mixed steaming and mixed burning'. [ABSTRACT FROM AUTHOR]

To comprehensively understand the volatile flavor composition of dry-rendered beef fat, solvent-assisted flavor evaporation (SAFE) with four extraction solvents (dichloromethane, pentane, ethyl ether, and methanol) combined with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactormetry (GC–O) were performed. GC–MS analysis found 96 different volatile compounds in total using the four extraction solvents. According to the GC–MS results and the heat map and principal component analysis (PCA), most of the volatile compounds resulted from dichloromethane and pentane extraction, followed by ethyl ether. Methanol extraction found a few volatile compounds of higher polarity, which was supplementary to the analysis results. Moreover, GC–O analysis found 73 odor-active compounds in total using the four extraction solvents. The GC–O results found that pentane and dichloromethane extraction had a significantly larger number of odor-active compounds than ethyl ether and methanol extraction. This indicated that pentane and dichloromethane were more effective solvents for the extraction of odor-active compounds than the other two solvents. Finally, a total of 15 compounds of odor-active values (OAVs) ≥ 1 were determined to be the key aroma compounds in the dry-rendered beef fat, including 2–methyl–3–furanthiol, 3–methylthiopropanal, (E,E)–2,4–nonadienal, 12–methyltridecanal, and 1–octen–3–one. [ABSTRACT FROM AUTHOR]

As a further extension of the deep processing technology of tea raw materials, tea aroma type distilled spirit combines the aroma of tea and wine, and has a unique flavor. In order to clarify the changes of flavor substances of tea aroma type distilled spirit under different processes, solid-phase microextraction/gas chromatography-mass spectrometry was used to analyze the flavor components. The odor specific magnitude estimation method and Odor activity value method in liquid-liquid extraction/gas chromatography-olfactometry-mass spectrometry were used to determine the characteristic flavor substances and their contribution to the overall flavor. The results show that 76 kinds of aroma substances were detected, including 32 esters, 14 alcohols, 10 aldehydes and ketones, 4 acids, 13 terpenes and 3 other substances. Gas chromatography-olfactometry mass spectrometry analysis results show that there were 21 aroma compounds that could be smelled, and 12 key aroma compounds were identified by OAV and OSME together, including linalool (rose flowers), anisole (herbal), ethyl caprate (fruit), ethyl caproate (wine aroma) and so on. The results show that different kinds of microorganisms, fermentation methods and distillation technology significantly affected the composition and contents of flavor substances in tea aroma type distilled spirit. The results of this study have important guiding significance for the characteristic aroma characterization and quality control of tea aroma type distilled spirit. [ABSTRACT FROM AUTHOR]

To understand the effects of particle size on the extraction of volatile huajiao (HJ) Zanthoxylum oils, Hanyuan pepper powder of 20, 30, 40, 60, and 80 mesh sizes was fried at 130 ℃ for 20 minutes with rapeseed oil as the extract oil. E-nose, gas chromatography-ion mobility spectrometry (GC-IMS), gas chromatography-mass spectrometer (GC-MS), odor activity value (OAV), and quantitative descriptive analysis (QDA) were applied to analyze the volatile Zanthoxylum oil components extracted from different sizes of pepper particles. Cluster analysis and Pearson correlation were performed to explore the differences in aroma profiles between samples. The E-nose and CA results indicated that the HJ-1 (20 mesh) sample was clearly different from other samples in terms of aroma, the aroma characteristics of HJ-4 (60 mesh) and HJ-5 (80 mesh) samples were similar, and the aroma characteristics of HJ-2 (30 mesh) and HJ-3 (40 mesh) samples were similar to each other. A total of 118 aromatic components were detected by GC-IMS, comprising 20 unidentified components and 98 identified components. The identified compounds included 13 aldehydes, 11 ketones, 12 alcohols, 22 esters, 16 heterocycles, seven acid, two phenolic compounds, and eight miscellaneous components. Moreover, the OAV values of 14 key aromatic components were greater than 1, including linalool, 2-furanmethanol, 2-phenylethanol, linalyl acetate, methyl phenyl acetate, γ-terpinene, phellandrene, and β-pinene. The key aromatic components of the HJ-4 sample contributed the most to the aroma of Zanthoxylum oil. QDA analysis revealed that the HJ-4 samples had very strong woody, lemon, nutty and fatty flavors. The Pearson correlation coefficient showed that the sensory property of lemon, woody, nutty and fatty flavors and concentrations of most key aromatic were strongly and positively correlated. From comprehensive analysis, the HJ-4 sample prepared from 60 mesh pepper powder was determined to have the best aroma sensory quality. In conclusion, GC-IMS and OAV values were able to identify the effect of different sizes of pepper particles during the extraction of volatile components of Zanthoxylum oil. This information could be used to provide a theoretical and practical reference for the production of Zanthoxylum oil.

At the dawn of a food transition encouraging the consumption of healthy and sustainable non-dairy probiotic products, the development of a fermented functional drink based on Sobacha is considered. Sobacha is an infusion of roasted buckwheat seeds widely consumed in Asian countries for its health benefits. As fermentation improves the nutritional and organoleptic status of grains, the mixed fermentation process involved in the development of kombucha beverages (fermented sweet tea) is conducted by inoculating a symbiotic culture of bacteria and yeasts into the transposable matrix (Sobacha instead of tea). Sobacha, a healthy pseudo-cereal matrix with promising aromas, could be fermented to potentially develop an innovative drink, named "Hakko Sobacha". This neologism would reveal the fermented character of the infusion, Hakko meaning fermented in Japanese. Considering the beverage characterization, the kinetics of the volatile organic compound syntheses were determined using stir-bar sorptive extraction followed by gas chromatography coupled to mass spectrometry analysis. Odor-active compounds were theoretically calculated to estimate the flavor composition. Finally, sensory analyses highlighted the appreciation and preferences of the consumer towards the beverages. The fermentative yield differences observed between the two buckwheat concentration modalities tested seemed to be correlated with the sugar and nutrient levels available from the starch (buckwheat) matrix. Having characterized Hakko Sobacha, this study proposed the possibility of developing new beverages by monitoring the fermentative process. This should enable improved control and enhancement of their sensorial properties, which could in turn lead to greater customer acceptability. [ABSTRACT FROM AUTHOR]

The increase in demand for food flavorings due to the shortening and simplification of food production technology also entails an increase in the demand for new technologies for their production. The biotechnological production of aromas is a solution characterized by a high efficiency, an independence from environmental factors and a relatively low cost. In this study, the influence of the implementation of lactic acid bacteria pre-fermentation into the production of aroma compounds by Galactomyces geotrichum on a sour whey medium on the intensity of the obtained aroma composition was analyzed. The monitoring of the culture in terms of biomass buildup, the concentration of selected compounds, and the pH resulted in the confirmation of interactions between the analyzed microorganisms. The post-fermentation product underwent a comprehensive sensomic analysis for the identification and quantification of the aroma-active compounds. The use of gas chromatography−olfactometry (GC−O) analysis and the calculation of odor activity values (OAVs) allowed 12 key odorants to be identified in the post-fermentation product. The highest OAV was found for phenylacetaldehyde with a honey odor (1815). The following compounds with the highest OAVs were 2,3-butanedione with a buttery aroma (233), phenylacetic acid with a honey aroma (197), 2,3-butanediol with a buttery aroma (103), 2-phenylethanol with a rosy aroma (39), ethyl octanoate with a fruity aroma (15), and ethyl hexanoate with a fruity aroma (14). [ABSTRACT FROM AUTHOR]

The GC-MS was used to qualitatively analyze the aroma components of red koji wine with low glucose fermented by biological hypoglycemic fermentation, and the OAV was further used to evaluate the changes of the characteristic aroma components and alcohol-ester ratios, so as to characterize the characteristic aroma components of red koji wine with low glucose fermented by biological hypoglycemic fermentation. The results showed that: (1) The red koji wine with low glucose fermented by biological hypoglycemic fermentation was salmon pink, with the elegant and mellow aroma, delicious and round taste, and harmonized wine body. And its sensory score was 96 points, which was better than that of the traditional sweet rice wine (the sensory score being 94 points). (2) The total sugar content of red koji wine with low glucose fermented by biological hypoglycemic fermentation was only 26 g ⋅ L-1, which was 79. 2% lower than that of the traditional sweet red koji wine. (3) A total of 32 kinds of volatile substances were identified in the red koji wine fermented by biological hypoglycemic fermentation and the control samples, including alcohols (7 kinds), esters (18 kinds), and the others (7 kinds). The highest proportion of volatile compounds was esters, followed by alcohols. Among them, the OAV values of 14 flavor substances such as ethanol, β-phenylethanol, 2,3-butanediol, ethyl acetate, ethyl caproate, isoamyl acetate and so on were all >1, which were important aroma components of the characteristic aroma of red koji wine. [ABSTRACT FROM AUTHOR]

The flavor and quality of tea largely depends on the cultivar from which it is processed; however, the cultivar effect on the taste and aroma characteristics of Hakka stir-fried green tea (HSGT) has received little attention. High-performance liquid chromatography (HPLC), gas chromatography–mass spectrometry (GC-MS), and sensory evaluations were used to detect and predict the essential taste and aroma-contributing substances of HSGTs made from Huangdan (HD), Meizhan (MZ) and Qingliang Mountain (QL) cultivars. Orthogonal partial least squares data analysis (OPLS-DA) ranked four substances that putatively distinguished the tastes of the HSGTs, epigallocatechin gallate (EGCG) > theanine > epigallocatechin (EGC) > epicatechin gallate (ECG). Ten substances with variable importance in projections (VIPs) ≥ 1 and odor activation values (OAVs) ≥ 1 contributed to their overall aromas, with geranylacetone having the most significant effect on HD (OAV 1841), MZ (OAV 4402), and QL (OAV 1211). Additionally, sensory evaluations found that HD was relatively equivalent to QL in quality, and both were superior to MZ. HD had a distinct floral aroma, MZ had a distinct fried rice aroma, and QL had a balance of fried rice and fresh aromas. The results provide a theoretical framework for evaluating the cultivar effect on the quality of HSGT and put forward ideas for future HSGT cultivar development. [ABSTRACT FROM AUTHOR]

Since the sensorial profile is the cornerstone for the development of kombucha as a beverage with mass market appeal, advanced analytical tools are needed to gain a better understanding of the kinetics of aromatic compounds during the fermentation process to control the sensory profiles of the drink. The kinetics of volatile organic compounds (VOCs) was determined using stir bar sorptive extraction—gas chromatography—mass spectrometry, and odor-active compounds were considered to estimate consumer perception. A total of 87 VOCs were detected in kombucha during the fermentation stages. The synthesis of mainly phenethyl alcohol and isoamyl alcohol probably by Saccharomyces genus led to ester formation. Moreover, the terpene synthesis occurring at the beginning of fermentation (Δ-3-carene, α-phellandrene, γ-terpinene, m- and p-cymene) could be related to yeast activity as well. Principal component analysis identified classes that allowed the major variability explanation, which are carboxylic acids, alcohols, and terpenes. The aromatic analysis accounted for 17 aroma-active compounds. These changes in the evolution of VOCs led to flavor variations: from citrus-floral-sweet notes (geraniol and linalool domination), and fermentation brought intense citrus-herbal-lavender-bergamot notes (α-farnesene). Finally, sweet-floral-bready-honey notes dominated the kombucha flavor (2-phenylethanol). As this study allowed to estimate kombucha sensory profiles, an insight for the development of new drinks by controlling the fermentation process was suggested. Such a methodology should allow a better control and optimization of their sensory profile, which could in turn lead to greater consumer acceptance. [ABSTRACT FROM AUTHOR]

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Citrus, as one of the most popular fruits in the world, besides their pulp, their peel has a unique flavor and rich value. Compared with pulp, the aroma of citrus peel is more intense and unique, and there are few comprehensive studies on the difference between citrus peel and pulp aroma properties. In this study, the aroma characterization of September Red navel orange (SRO) pulp (OPU) and peel (OPE) was investigated by gas chromatography–mass spectrometry (GC–MS), gas chromatography–olfactometry (GC–O), odor activity value (OAV) determination and sensory analysis. Terpenes, alcohols, and aldehydes were found as the major volatile compounds in SRO, meanwhile, 23 key aroma components were detected, with 15 of them present in both OPU and OPE, and the concentration of the 15 substances in OPE was 1–1700 times higher than in OPU. The quantitative descriptive analyses (QDA) sensory analysis results showed there were six main fragrances present, with "fruity", "green", "floral", and "woody" significantly stronger (p < 0.05) in OPE than in OPU. Finally, (E)-2-pentenal, ethyl butyrate, (E)-2-decenal, styrene, (Z)-3-hexen-1-ol, (Z)-2-hexen-1-ol, linalool, nerol, γ-terpinene, and acetic acid were summarized as the key aroma compounds by aroma recombination and omission experiments. This study expands our knowledge of orange aroma characterization and not only provides theoretical basis for natural fruit flavor products, but also helps to promote the healthy development of the flavor industry. [ABSTRACT FROM AUTHOR]