Odor Activity Values Research Articles

The dynamic of physicochemical properties, volatile compounds and microbial community during the fermentation of Chinese rice wine with diverse cereals

This study investigates the impact of liquid state fermentation on the key flavor compounds and microbial community structure in Chinese rice wine brewed from five different raw materials: buckwheat, sorghum, japonica rice, glutinous rice, and black rice. Using HS-SPME-GC–MS and HPLC, the volatile compounds were analyzed across various grain liquefaction methods, detecting 82 volatiles, including esters, alcohols, aldehydes, and acids. The concentration of flavor compounds such as esters, amino acids, phenolic acids, and organic acids varied significantly depending on the raw material used. Based on odor activity values, 31 key compounds were identified, including 15 ethyl esters, like ethyl laurate, responsible for the unique and complex aroma of the rice wines. Bitter amino acids, making up over 50 % of the total amino acids, were predominant. Among the varieties, the buckwheat-fermented wine exhibited the highest ester content (27.39 mg/L), nearly double that of other samples, along with elevated amino acids (1.47 mg/mL) and phenolic acids (904.29 mg/L). Black rice ranked second in amino acid content (0.93 mg/mL), while glutinous rice had the highest organic acid content (239.76 mg/mL). Metagenomic sequencing on the fifth day of fermentation revealed significant differences in microbial community structure among the raw materials. Saccharomyces, Aspergillus, Thermomyces, Epicoccus, and Albertella were dominant fungi, while Weissella, Thermoactinomyces, Bacillus, and Saccharopolyspora were dominant bacteria. Sensory analysis showed that buckwheat-fermented rice wine was distinguished by its honey, floral, creamy, and umami attributes, while balancing alcohol, acidity, bitterness, and Qu aroma. The results demonstrate the significant influence of raw material selection and liquefaction method on both flavor profile and microbial diversity in Chinese rice wine.

Comparative characterization of key compounds of Sauce-flavored rounded-Baijiu in northern and southern China and the potential possibility of similar quality of their combined products

The flavor characteristics and sensory attributes of northern Sauce-flavored rounded-Baijiu (NR) and southern Sauce-flavored rounded-Baijiu (SR) were systematically studied. A total of 56 major flavor compounds were quantitatively detected through Gas chromatography-flame ionization detection (GC-FID). Besides, 20 kinds of key aroma compounds and 7 significant differential compounds were identified by calculating the odor activity values (OAVs) and orthogonal partial least squares discriminant analysis (OPLS-DA) of flavor compounds in NR and SR. And then, the relationship between sensory attributes and key aroma compounds were investigated by network analysis. Furthermore, A group of combined-Baijiu (the ratios of the first to the fifth round of Sauce-flavored Baijiu in the north (NR1–5) were 5 % NR1, 35 % NR2, 30 % NR3, 20 % NR4, 10 % NR5) was closer to the style known for blending different proportions of SR into the combined-Baijiu. This study provided a guiding significance for the standardized production of sauce-flavored Baijiu.

Characteristics of volatile flavor development in aged longissimus lumborum post-ultrasound treatment: 4D proteomics combined with phosphoproteomics analysis

The present study aimed to evaluate the impact of ultrasonic treatment on the development of volatile flavor compounds in beef during postmortem aging and its potential mechanism. Results showed that ultrasound treatment may cause an increase in the total content of unsaturated fatty acids, which could lead to lipid oxidation and potentially result in changes in the flavor development. Additionally, it was also found that ultrasound exacerbated protein oxidation. A total of 141 volatile compounds were obtained by SPME–GC–MS analysis, and 18 differential aroma substances (P < 0.05, VIP > 1) were obtained by orthogonal partial least squares discrimination analysis (OPLS-DA). Five key volatile flavor compounds (hexanal, nonanal, octanal, pentanal, and 1-pentanol) originating from lipid oxidation were identified according to odor activity values (OAVs). The concentration of these compounds was significantly higher in the ultrasonic treatment group compared to the non-ultrasonic group that underwent a 3-day aging process. Nine common differentially expressed proteins (DEPs) were identified through the utilization of proteomics and phosphoproteomics analysis. KEGG pathways showed that selenocompound metabolism, tryptophan metabolism and cysteine and methionine metabolism led to flavor formation during wet aging of beef after ultrasound treatment. This study provided proteomic insights into the flavor of beef aged through sonication and suggested potential links between flavor development and biological processes.

Comparative Investigation of Aroma-Active Volatiles in ("Ruixue", "Liangzhi", "Crystal Fuji," and "Guifei") Apples by Application of Gas Chromatography-Mass Spectrometry-Olfactometry (GC-MS-O) and Two-Dimensional Gas Chromatography-Quadrupole Mass Spectrometry (GC × GC-qMS) Coupled with Sensory Molecular Science.

Aroma dramatically impacts the overall flavor profiles and consumer acceptance; therefore, it is necessary to conduct a comprehensive analysis of the aroma characteristics of apples. In this study, the aroma differences among four popular apple varieties ("Ruixue", "Liangzhi", "Crystal Fuji," and "Guifei") were compared using two extraction methods (headspace-solid phase microextraction, and solvent-assisted flavor evaporation) coupled with gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-qMS). A total of 82 odorants were identified via GC-MS-O, and 143 volatiles were identified by GC× GC-qMS. Among them, 41 key aroma-active compounds (butanal, ethyl acetate, 3-methylbutanal, methyl butanoate, 2-methylpropyl acetate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, butyl acetate, hexanal, 2-methylbutyl acetate, 1-butanol, 2-methylpropyl butanoate, 3-methylbutyl acetate, (E)-2-hexenal, butyl butanoate, butyl 2-methylbutanoate, hexyl acetate, hexyl butanoate, hexyl, 2-methylbutanoate, 1-octen-3-ol, 3-methylthiopropanol, 1,3-octanediol, linalyl acetate, and so on) with high odor activity values (OAVs) and AI value (odor activity values ≥1 or aroma intensity ≥3) were identified. Partial least-squares-discriminant analysis showed that Ruixue exhibited a high "fruity" note, Guifei and Crystal Fuji had the greatest "wood," "floral," and "sweet" notes, while Liangzhi presented a significant "green" note. This study provided flavor chemistry support for the apple quality control and production.

Nutrition, Flavor, and Microbial Communities of Two Traditional Bacterial Douchi from Gansu, China.

Douchi has attracted attention for its unique taste and rich health functions. This study investigated the nutrition, flavor and correlation between the flavor and microorganisms of two traditional bacterial douchi from the province of Gansu in northwest China. The findings reveal significant variations in nutrition, flavor compounds, and the microbiota between Longnan and Qingyang douchi. Three dominant bacterial genera (Carnobacterium, Ignatzschineria, and Bacillus) and one dominant bacterial genus (Pichia) were found in the QY douchi, while four bacterial genera (Bacillus, Ignatzschineria, Proteus, and Providencia) and three fungal genera (Pichia, Candida, and Rhodosporidium) were dominant in samples of the LN douchi. For flavor substances, a total of 48 volatile components were detected in Longnan douchi and 41 in Qingyang douchi. Using the relative odor activity value (ROAV), we identified five key flavor compounds in Longnan douchi and four key flavor compounds in Qingyang douchi. The correlation analysis showed that there were certain positive or negative correlations between the key microorganisms and the flavor of the two traditional bacterial douchi. The results of this study can serve as a theoretical reference for improving the quality and flavor of traditional douchi.

Study on Evaluation of Fruit Aroma of Plum Variety Resources Based on Headspace Solid-Phase Microextraction Combined with Gas Chromatography-Mass Spectrometry.

To explore the characteristics of and variations in aroma components across different plum varieties and maturity stages, this study employed headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). This method was used to systematically analyze the aroma components of 12 early-maturing, 15 medium-maturing, and 11 late-maturing plum varieties. The variations in volatile components among these three germplasm types were then compared using multivariate statistical methods. The examination revealed that 138 aromatic components were meticulously identified and quantified, such as 26 aldehydes, 63 esters, 13 ketones, 30 alcohols, and six other compounds. Thirteen main aroma compounds including acetic acid hexyl ester, (Z)-3-hexen-1-ol acetate, hexanal, 1-hexanol, 3-hexenal, butanoic acid butyl ester, (E)-2-hexen-1-ol, hexanoic acid butyl ester, propanoic acid butyl ester, (E)-2-hexenal, L-.alpha.-terpineol, (Z)-2-hexen-1-ol acetate, and 1-butanol were considered dominant. The orthogonal partial least squares discriminant analysis (OPLS-DA) combined with variable importance projection (VIP) results showed that 24 differential aroma compounds were screened out from 38 varieties of plum fruits based on their differences in aroma components, which can be used to distinguish plum fruits at different ripening times. Twenty-four aroma-contributing compounds were identified based on their odor activity values (OAVs). Among these, 14 key aroma components with OAVs ≥ 10 were highlighted. In summary, the aroma compounds of early- and late-maturing plum germplasm exhibited rich diversity, with significant differences in aroma components between plums of varying maturity and germplasm. These differences can serve as indicators for identifying different plum germplasm.

Characterization of Important Odorants in Dried Lobster Mushrooms.

Lobster mushrooms, a type of wild edible mushroom that primarily grows in North America, have a distinctive aroma resembling seafood and are highly desired by fine dining establishments and food enthusiasts. Lobster mushrooms have a short collection season; therefore, they are usually dried for a year-round sale. Owing to their rising popularity, lobster mushrooms have become one of the most expensive mushroom species in the dried mushroom market. Herein, 35 odorants were identified from dried lobster mushrooms using solvent assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA). Fourteen odorants were quantitated using stable isotope dilution assays (SIDA), and their odor activity values (OAVs) were calculated. Eleven of the quantitated odorants exhibited OAVs of ≥1. Some notable odorants with relatively high OAVs included 2-acetyl-1-pyrroline (OAV 730), γ-nonalactone (OAV 410), 1-octen-3-one (OAV 180), and sotolon (OAV 170). The organohalogen molecule 2,6-dichlorophenol was determined to be key to the seafood aroma character of the mushrooms. An aroma simulation model formulated based on the quantitation data closely matched the aroma profile of the dried mushrooms. This study lays the groundwork for future studies aimed at understanding the effect of processing on lobster mushroom aroma chemistry and the biotechnological production of natural seafood flavors.

Analysis of volatile compounds in Xiangjiao baijiu from different storage containers and years based on HS-GC-IMS and DI-GC–MS

The volatile compounds in 16 different storage containers and years of Xiangjiao Baijiu (XJBJ) were compared and analyzed via direct injection (DI) combined with gas chromatography–mass spectrometry (GC–MS) and headspace extraction (HS) coupled with gas chromatography-ion mobility spectrometry (HS-GC-IMS) for the first time. Through HS-GC-IMS analysis, it was found that the succession rules of 14 compounds such as furfural during aging process. A total of 60 compounds were identified using DI-GC–MS. Twenty-five of these compounds were further quantified, and 18 compounds had odor activity values (OAVs) > 1, which were important contributor to aroma of XJBJ. Among them, those with OAVs >1000 included ethyl hexanoate, ethyl octanoate, ethyl butanoate, and ethyl pentanoate. Combining the results of quantitative, OAVs and partial least squares-discriminant analysis (PLS-DA) revealed that 10 compounds such as ethyl octanoate were the important compounds that lead to the differences between different storage types of XJBJ.

HS–SPME combined with GC–MS and GC–O for characterization of key aroma-active compounds in fruity and grassy peppers (Capsicum chinense Jacq.)

Pepper (Capsicum spp.) is highly popular due to its unique flavor. However, there was limited research on the primary volatiles that influence the different flavors of fresh peppers. In this study, peppers with three aroma compound types denoted as “grassy,” “fruity,” and “no special aroma” (control) were analyzed using sensory evaluation combined with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). Altogether, 393 volatiles were identified by GC–MS, and the main volatiles in peppers (C. chinense Jacq.) were esters and terpenoids. GC–O and relative odor activity value analysis revealed that 2-isobutyl-3-methoxypyrazine had a highly bitter, spicy aroma intensity in all peppers. Hexanal and trans-2-hexenal were the main aroma-active compounds in grassy peppers. In addition, citronellal was determined to be a crucial aroma-active compound in fruity peppers. This study offers a theoretical foundation for guiding the growth of the pepper processing industry and breeding.

HS-SPME-GC-MS combined with relative odor activity value identify the key aroma components of flowery and fruity aroma in different types of GABA tea

HS-SPME-GC-MS combined with relative odor activity value identify the key aroma components of flowery and fruity aroma in different types of GABA tea

Volatile flavor characteristics of scallops (Chlamys farreri) with different drying methods were analyzed based on GC-IMS and GC-O-QTOF

To investigate the effects of different drying methods on the flavor of scallops, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with gas chromatography-olfactometry-quadrupole time-of-flight (GC-O-QTOF) was used to analyze the flavor of scallops processed by five drying methods. A total of 62 volatile organic compounds (VOCs) were identified by GC-IMS. 27 characteristic aroma compounds were identified by GC-O-QTOF, and the highest content was trimethylamine. 17 aroma compounds with GC-O ≥ 6 were screened by the time-intensity method, and the maximum aroma intensity value of 2-acetyl-1-pyrroline was 9.9 aroma compounds with relative odor activity value (ROAV) ≥ 1 were identified. Using GC-O ≥ 6 and ROAV ≥1 as the criteria, 6 differential aroma compounds were further screened, and the results proved that naturally dried scallops had a heavier fishy odor. These findings will provide deeper insights into the processing of scallops.

Comparative characterization of flavor precursors and volatiles in Chongming white goat of different ages by UPLC-MS/MS and GC–MS

Age has a significant impact on goat meat flavor. However, reporting the effects of age on free amino acid (FAAs), lipid profiles and aromas of goat meat is limited. Here, the FAAs, lipid profiles and aromas in the Chongming white goat with 12 months and 24 months were investigated in this study. A total 1164 lipids were identified using lipidomics, including 31 subclasses. Multivariate statistical analysis showed that 201 lipids had significant changes, FFA, TG and DG increased with goat age. Furthermore, the pathway analysis indicated that glycerophospholipid metabolism and glycerolipid metabolism were the key pathways that relate to lipid profile changes during goat growth. Thirty-five volatile compounds were identified, among them, 14 aromas with odor activity value greater than 1 were considered as potential characteristic aroma compounds of Chongming white goat meat. These findings reveal the FAAs, lipids, and aromas profiles in Chongming white goat meat are affected by age, which provides a basis for improving goat meat flavor.

Influence of inoculation with different non-Saccharomyces yeasts and Saccharomyces cerevisiae on the aroma chemical composition and sensorial features of red dragon fruit wine

Abstract In this investigation, we focused on elucidating the impact of non-Saccharomyces yeasts on both the aromatic chemical composition and sensory attributes of red dragon fruit wine. This was achieved through the introduction of Hanseniaspora uvarum or Pichia guilliermondii concurrently with Saccharomyces cerevisiae, employing methodologies encompassing co-inoculation or sequential inoculation. The findings suggested that the combined inoculation of non-Saccharomyces yeasts and S. cerevisiae is capable of modulating the sensory properties of wines. Additionally, varying inoculation methods exerted a significant impact on the aromatic qualities of the wine. Co-inoculation and sequential inoculation of H. uvarum or P. guilliermondii with S. cerevisiae demonstrated a remarkable augmentation in the quantity of volatile chemicals while effectively regulating the number of odor activity value (OAV) &gt; 1 in the wine. Therefore, the utilization of mixed fermentation emerges as a viable strategy for regulating the flavor profile of red dragon wine. This methodology stands as a valuable guideline for making various fruit wines, including red dragon fruit wine.

Effects of Five Different Withering Methods on the Composition and Quality of Congou Black Tea.

To explore the effects of different withering methods on the quality of Congou black tea, this study focused on five different withering methods: natural withering, warm-air withering, sun-natural combined withering, sun withering, and shaking withering. Gas chromatography‒mass spectrometry (GC‒MS), high-performance liquid chromatography (HPLC), and ion-exchange chromatography techniques were used to analyze the nonvolatile and volatile components and composition of the tea. The results revealed significant differences (p < 0.05) in the contents of nonvolatile constituents including caffeine, polyphenols, soluble sugars, free amino acids and their components, theaflavins, thearubigins, and catechins among the five different withering methods, with varying degrees of correlation between these components. A total of 227 aroma compounds were detected, and significant differences in the contents of alcohols, aldehydes, and ketones were observed. A relative odor activity value (ROVA) analysis of the aroma compounds revealed that 19 compounds had an ROVA > 1. Among them, benzylaldehyde, trans-2-decenal, decanal, benzaldehyde, nonanal, hexanal, trans-linalool, and geraniol from the shaking withering method had significantly higher ROVA values than those from the other withering methods, which may be the reason for the prominent floral and fruity aroma of shaking withering. This study revealed the impact of different withering methods on the quality of Congou black tea, providing a scientific basis for the development of Congou black tea with different flavors and the improvement of Congou black tea processing techniques.

Impact of Mild Field Drought on the Aroma Profile and Metabolic Pathways of Fresh Tea (Camellia sinensis) Leaves Using HS-GC-IMS and HS-SPME-GC-MS.

Aroma plays a pivotal role in defining tea quality and distinctiveness, and tea producers have often observed that specific drought conditions are closely associated with the formation and accumulation of characteristic aroma compounds in tea leaves. However, there is still limited understanding of the differential strategies employed by various tea cultivars in response to drought stress for the accumulation of key volatile aroma compounds in fresh tea leaves, as well as the associated metabolic pathways involved in aroma formation. In this study, two widely cultivated tea cultivars in China, Fuding Dabai (FD) and Wuniuzao (WNZ), were examined to assess the impact of mild field drought stress on the composition and accumulation of key volatile aroma compounds in fresh leaves using headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) and headspace solid phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) technologies. Results revealed that drought stress led to a substantial increase in the diversity of volatile compounds (VOCs) in FD, while WNZ exhibited a notable rise in low-threshold VOC concentrations, amplifying sweet, floral, fruity, and earthy aroma profiles in post-drought fresh leaves. Through partial least squares discriminant analysis (PLS-DA) of HS-GC-IMS and HS-SPME-GC-MS data, integrating variable importance projection (VIP) scores and odor activity values (OAVs) above 1, 9, and 13, key odor-active compounds were identified as potential markers distinguishing the drought responses in the two cultivars. These compounds serve as crucial indicators of the aromatic profile shifts induced by drought, providing insights into the differential metabolic strategies of the cultivars. Additionally, KEGG enrichment analysis revealed 12 metabolic pathways, such as terpenoid biosynthesis, fatty acid synthesis, cutin, suberine, and wax biosynthesis, and phenylalanine metabolism, which may play crucial roles in the formation and accumulation of VOCs in tea leaves under drought stress. These findings provide a comprehensive framework for understanding the cultivar-specific mechanisms of aroma formation and accumulation in tea leaves under mild drought conditions.

Aroma characterization of Sichuan and Cantonese sausages using electronic nose, gas chromatography–mass spectrometry, gas chromatography-olfactometry, odor activity values and metagenomic

The interest of Chinese consumers in meat-free sausages has increased considerably due to their health benefits, but the aroma quality is far from reaching the traditional fermented meat sausages. This study evaluated the aroma characterization of Sichuan and Cantonese sausages using electronic nose (E-nose), gas chromatography–mass spectrometry (GC–MS), gas chromatography-olfactometry (GC-O), odor activity values (OAVs) and metagenomic. Ninety-eight volatile compounds were identified. Among them, 23 odorants were perceived, and their intensity differed in the two groups of sausages. There was a significant difference in the volatile compound profile between Sichuan and Cantonese cooked sausages. E-nose sensors could differentiate them through specific responses to these volatile compounds. Furthermore, there was a significant difference in microbial communities between Sichuan and Cantonese sausages. For aroma quality improvement of meat-free sausages, studies should focus on controlling the formation of aroma compounds by aroma precursors and using different microorganisms to produce diverse meat aromas. Our results provide a reference for the implementation of these strategies.

Comparative study of volatile compounds of cold-pressed oils extracted from three different oilseeds after gamma irradiation.

To investigate the effect of gamma irradiation on the volatile compounds of edible oils. Three types of oilseeds, including peanut, sesame, and flaxseed, were subjected to 8 kGy gamma irradiation, followed by cold pressing to extract their oils. The volatile compounds of the oils were isolated by simultaneous distillation extraction and analyzed by gas chromatography-mass spectrometry. A total of 91 volatile compounds were identified, which can be grouped into eight categories: hydrocarbons, aldehydes, ketones, alcohols, acids, esters, furans, and benzene derivatives. Irradiation treatment resulted in a significant increase in the levels of hydrocarbons, aldehydes, and ketones in all oil samples (p<0.05), with the greatest increase observed in hydrocarbons (4-14 times). In contrast, changes in alcohols, acids, esters, furans, and benzene derivatives were related to oilseed type. The increased hydrocarbons mainly originated from the degradation of palmitic, stearic, oleic, and linoleic acids. The irradiation resistance of the three oilseeds varied considerably, in the order: flaxseed>sesame>peanut. Based on the odor activity value, 11 key aroma compounds were selected, and (E)-2-decenal (tallow, oily, and orange), 1-octanol (soapy and oily), and 1-nonanol (floral and soapy) were only detected in the irradiated samples. Principal component analysis revealed that the oil samples of the three oilseeds could be well classified based on their key aroma compounds, and that the irradiation treatment had no remarkable effect on their intrinsic aroma.

Effect of inoculation with different Eurotium cristatum strains on the microbial communities and volatile organic compounds of Fu brick tea

Eurotium cristatum is the primary fungus in Fu brick tea (FBT) and plays a crucial role in its special flavor. This study investigated the effect of inoculation with different E. cristatum strains (i.e., ZJ, GX, GZ, HN, and SX) on the microbial communities and volatile organic compounds (VOCs) of FBT. A total of 113 VOCs were identified in all samples, with the concentration of VOCs (alcohols, aldehydes, and ketones) significantly higher in GXE FBT than in other samples. The core VOCs of GXE (19), GZE (16), HNE (19), SXE (15), and ZJE (13) FBT were identified using orthogonal partial least squares discriminant analysis and relative odor activity value (ROAV) analysis. Methional (a27), butanal (a41), 1-octen-3-one (a69), and ethyl acetate (a77) were key markers for inoculated FBTs, and 1-octen-3-ol, dimethyl disulfide, and acetoin-M were the specific markers of HNE. Linalool and (E)-2-octenal were particularly prominent in GXE, and isoamyl acetate-D was an important aroma component of GZE. Differences in microbial diversity were observed among the different inoculated fermented FBTs, and E. cristatum inoculation remarkably influenced the richness and diversity of bacterial communities. The VOCs were closely associated with fungi and bacteria, and 19 potentially dominant microorganisms (10 fungal and 9 bacterial genera) correlated with VOCs were identified. Among them, Aspergillus (fungi) and Pseudomonas (bacteria) exerted the greatest role. The FBT inoculated with E. cristatum from ZJ had the highest content of theaflavins and theabrownins, which intensified the red and yellow colors of the tea. E. cristatum greatly decreased the free amino acids and fatty acids, contributing to the aroma formation of FBT. Therefore, inoculating FBT with E. cristatum remarkably influenced the microbial communities and improved its flavor profile. This work provides a theoretical foundation on the role of E. cristatum in the formation and regulation of FBT flavor.

Regional aroma characteristics of spontaneously fermented Cabernet Sauvignon wines produced from seven sub-regions in Shangri-La of China.

Shangri-La is a promising wine region in China, which has great potential for producing high-quality wines with distinctive regional characteristics. In this work, the aroma properties of spontaneously fermented Cabernet Sauvignon wines produced from seven sub-regions of Shangri-La (Adong, Liutongjiang, Sinong, Xidang, and Nitong from Lancang River basin; Benzilan and Dari from Jinsha River Basin) were comprehensively analyzed using the headspace micro-extraction with gas chromatography-mass spectrometry, odor activity values, and olfactory evaluation. Results showed that a total of 59 volatiles belonging to seven groups were identified and quantified in all regional wines, with alcohols constituting the most abundant group, followed by esters and volatile fatty acids. Based on their odor activity values, six alcohols, seven esters, two terpenes, one C13-norisoprenoids, and three volatile fatty acids were identified as key volatiles which significantly contribute to the aroma of these wines. Principal component analysis showed the distinct compositions of these 19 key volatiles among the seven regional wines. Olfactory evaluation revealed certain differences in aroma profiles, particularly "Tropical fruit", "Dried fruit", "Vegetal", and "Sweet" among them. This study enhances our understanding on the unique terroir flavors of Shangri-La wines and is helpful for further producing high-quality wines with regional characteristics.

Characterization of Odorants in Clustered Mountain Mint Pycnanthemum muticum.

The clustered mountain mint, Pycnanthemum muticum, is a pleasant-smelling, native North American plant. Despite its wide geographical presence across the United States and Canada, little is known about the specific odorants responsible for its pleasing aroma. Herein, 42 odorants were identified in the plant through solvent-assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS). Subsequent analysis involved determining flavor dilution (FD) factors using aroma extract dilution analysis (AEDA), quantitating 14 odorants through stable isotope dilution assays (SIDA), and calculating their odor activity values (OAVs). Several noteworthy odorants with OAV ≥ 1 included pulegone (mint, medicinal; OAV 276), 1-octen-3-one (mushroom; OAV 149), menthofuran (mint, petrol; OAV 139), nonanal (citrus; OAV 21), γ-nonalactone (coconut; OAV 13), 1,8-cineole (eucalyptus; OAV 12), mintlactone (mint, coconut; OAV 12), menthone (mint, fresh; OAV 7.3), α-pinene (pine; OAV 4), and piperitenone (mint; OAV 1.9). The study also determined the stereochemistry of various chiral odorants. An aroma simulation model was developed to validate the identification and quantitative results; upon evaluation using olfactory profile analysis, no significant differences were found between the aroma model and an aqueous infusion of P. muticum (P > 0.05). These findings lay the foundation for future investigations into the diversity of P. muticum selections and can provide valuable insights for studies on plant hybridization for food and flavor applications.