Search Results (45)

Background: Phoebe zhennan and Phoebe chekiangensis are valuable evergreen trees recognized for their unique aromas and ecological significance, yet the organ-related distribution and functional implications of aroma-active volatiles remain insufficiently characterized. Methods: In this study, we applied an integrated GC-MS-based volatile metabolomics approach combined with a relative odor activity value (rOAV) analysis to comprehensively profile and compare the volatile metabolite landscape in the seeds and leaves of both species. Results: In total, 1666 volatile compounds were putatively identified, of which 540 were inferred as key aroma-active contributors based on the rOAV analysis. A multivariate statistical analysis revealed clear tissue-related separation: the seeds were enriched in sweet, floral, and fruity volatiles, whereas the leaves contained higher levels of green leaf volatiles and terpenoids associated with ecological defense. KEGG pathway enrichment indicated that terpenoid backbone and phenylpropanoid biosynthesis pathways played major roles in shaping these divergent profiles. A Venn diagram analysis further uncovered core and unique volatiles underlying species and tissue specificity. Conclusions: These insights provide an integrated reference for understanding tissue-divergent volatile profiles in Phoebe species and offer a basis for fragrance-oriented selection, ecological trait evaluation, and the sustainable utilization of organ-related metabolic characteristics in breeding and conservation programs. Full article

In spite of the increasing industrial cultivation of lavender (Lavandula angustifolia Mill.), no genetic linkage map and mapping of QTLs (quantitative trait locus) has been reported for Lavandula species. We present the development of a set of SSR (simple sequence repeat) markers and the first genetic linkage map of lavender following the genotyping of a segregating population obtained by the self-pollination of the industrial lavender variety Hemus. The resulting genetic map comprises 25 linkage groups (LGs) corresponding to the chromosome number of the lavender reference genome. The map includes 375 loci covering a total of 2631.57 centimorgan (cM). The average marker distance in the established map is 7.01 cM. The comparison of the map and reference genome sequence shows that LG maps cover an average of 82.6% of the chromosome sequences. The PCR amplification tests suggest that the developed SSR marker set possesses high intra-species (>93%) and inter-species (>78%) transferability. The QTL analysis employing the constructed map and gas chromatography/mass spectrometry (GC/MS) dataset of flower extracted volatiles resulted in the mapping of a total of 43 QTLs for the accumulation of 25 different floral volatiles. The comparison of the genome location of the QTLs and known biosynthetic genes suggests candidate genes for some QTLs. Full article

Better quality and odor of silage and normal microbial fermentation metabolism are mostly dependent on an appropriate moisture content. The purpose of this study was to determine the effects of different moisture content gradients (50, 60, 70, and 80%) on the bacterial community, odor, and quality of alfalfa silage at 60 days by using gas chromatography–mass spectrometry (GC–MS) and electronic nose, with six replicates per group. The results showed that there were significant differences in odor response intensity among all groups, among which the 80% group had the strongest reaction to terpenoids, sulfides, and nitrogen oxides. Similarly, the different volatile organic compounds (VOCs) were mainly terpenoids, alcohols, and ketones, such as pine, camphor, and menthol (e.g., carlin and levomenthol). The dominant bacterium was Enterococcus with higher fiber, pH, and ammonia nitrogen (NH₃-N) content but poorer quality and odor (p < 0.05). The differential VOCs in the 60% group were mainly heterocyclics, esters, and phenols with fruity, floral, and sweet odors such as 2-butylthiophene and acorone. Pediococcus and Lactiplantibacillus were the dominant bacteria, with higher crude protein (CP), water-soluble carbohydrates (WSC), and lactic acid (LA) contents, as well as better quality and odor (p < 0.05). The biosynthesis of terpenoids and steroids, biosynthesis of secondary metabolites, and biosynthesis of phenylpropanoids were the main metabolic pathways of differential VOCs. In conclusion, regulating moisture content can alter bacterial community and metabolites, which will encourage fermentation and enhance alfalfa silage quality and odor. Full article

Background: Black tea processing conditions significantly affect the final taste and flavor profiles, so researchers are now focusing on developing equipment and improving the appropriate processing conditions of major black tea varieties. Methods: Here, we tested the effect of four different initial drying temperatures, i.e., R65 (65 °C), R85 (85 °C), R105 (105 °C), and R125 (125 °C), on the sensory and biochemical profiles and volatilome of the black tea variety “Lishui wild” (LWV). Results: Our results indicate that both 85 and 105 °C are better than 65 and 125 °C for initial drying for 20 min. R105 had the highest sensory evaluation scores due to better shape, aroma, taste, leaf base, thearubigins, theanine, caffeine, and ratio of theaflavins + thearubigins to theaflavins. Both R85 and R105 had higher catechins than R65 and R125. The LWV volatilome consisted of esters (19.89%), terpenoids (18.95%), ketones (11.3%), heterocyclic compounds (9.99%), and alcohols (8.59%). In general, acids, aldehydes, amines, aromatics, ethers, hydrocarbons, phenols, sulfur compounds, and terpenoids accumulated in higher amounts in R85 and R105. The highly accumulated compounds in R105 were associated with green, fruity, sweet, woody, floral, hawthorn, mild, nutty, powdery, rose, and rosy flavors. The main pathways affected are secondary metabolites, sesquiterpenoid and triterpenoid biosynthesis, glycerolipid metabolism, zeatin biosynthesis, phenylpropanoid biosynthesis, ABC transport, glutathione metabolism, etc. Therefore, R105 can be used to achieve the optimal taste, flavor, and aroma of LWV. Conclusions: Overall, the presented data can be used by the tea industry for processing black tea with the most optimum volatile substances, catechins, theanine, amino acids, and other compounds. Full article

Gracilaria fisheri (GF) is a red seaweed that is widely found in Southeast Asia and has gained attention for its potential bioactive compounds and versatile applications in food products. This study explored the potential of GF as a natural gelling agent in the development of sustainable strawberry-based drinking jelly. By utilizing GF at varying concentrations (0.2 (S1), 0.4 (S2), 0.6 (S3), 0.8 (S4), and 1.0% (S5)), the impact on the physicochemical, textural, phytochemical, and flavor profiles of the strawberry concentrate-based drinking jelly was examined. The results demonstrated that GF concentration significantly affected the color characteristics, structural development, and flavor profiles of the drinking jelly samples. Increasing GF levels progressively enhanced the lightness (L*) and redness (a*) values while reducing the yellowness (b*), with optimal visual appeal achieved in the S4 samples compared to others. Microscopical observations revealed that gel matrix development improved with GF concentrations up to 0.8% (S4), transitioning from a sparse, liquid-like structure at lower levels to a compact, over-gelated network at 1.0% (S5). Physicochemical parameters, including pH, total soluble solid (TSS), and TSS/titratable acidity (TA) ratios, increased with GF levels, contributing to a sweeter, less acidic product, while water activity (a_w) decreased, enhancing jelly stability. Viscosity and sulfate content increased significantly with GF concentration, indicating improved gel strength but reduced fluidity. Phytochemical analysis revealed that ascorbic acid (AsA) and total phenolic content (TPC) decreased progressively with higher GF levels, leading to a reduction in antioxidant activity (DPPH and ABTS). Volatile compound analysis identified alcohols, esters, and aldehydes as dominant contributors to the flavor profile. 1-Octanol (waxy, citrus-like) and methyl anthranilate (grape-like, sweet) increased substantially, while minor groups such as terpenoids and phenolic compounds contributed floral and woody notes. The findings suggest that S4 samples strike the optimal balance between texture, color, flavor, and antioxidant properties, achieving a cohesive, visually appealing, and flavorful drinking jelly suitable for commercial applications. Full article

Lilies (Lilium spp.) are renowned for their diverse and captivating floral scents, which are highly valued both commercially and ornamentally. This review provides a comprehensive overview of recent advancements in the identification, biosynthesis, and regulation of fragrance components in lily flowers. Various volatile organic compounds (VOCs) that contribute to the unique scents of different lily species and cultivars, including terpenoids, benzenoids/phenylpropanoids, and fatty acid derivatives, are discussed. The release patterns of these compounds from different floral tissues and at different developmental stages are examined, highlighting the significant role of tepals. Detection methods such as gas chromatography–mass spectrometry (GC-MS) and sensory analysis are evaluated for their effectiveness in fragrance research. Additionally, the biosynthetic pathways of key fragrance compounds are explored, focusing on the terpenoid and benzenoid/phenylpropanoid pathways and the regulatory mechanisms involving transcription factors and environmental factors. This review also addresses the influence of genetic and environmental factors on fragrance production and proposes future research directions to enhance the aromatic qualities of lilies through selective genetic and breeding approaches. Emphasis is placed on the potential applications of these findings in the floral industry to improve the commercial value and consumer appeal of lily flowers. Full article

Terpenes are critical components of the floral fragrance component in Dendrobium chrysotoxum, synthesized by terpene synthase (TPS). Analysis of the D. chrysotoxum genome and transcriptional data revealed that the gene DcTPSb1 was significantly up-regulated during flowering periods, showing a strong correlation with the accumulation of aromatic monoterpenes in the floral components of Dendrobium chrysotoxum. Consequently, the DcTPSb1 gene was selected for further analysis. DcTPSb1 exhibited elevated expression levels in flowers among four organs (roots, stems, leaves, flowers) of D. chrysotoxum, with the highest expression observed during the blooming phase, which aligned with the accumulation of volatile terpenes during flowering. DcTPSb1, located in the chloroplasts, was identified as a member of the TPS-b subfamily associated with monoterpenes synthesis, showing close phylogenetic relationships with homologous proteins in related plant species. An analysis of the promoter region of DcTPSb1 indicated that it may be regulated by methyl jasmonate (MeJA) responsiveness. Functionally, DcTPSb1 was shown to catalyze the conversion of geranyl diphosphate (GPP) to linalool, ocimene, and (-)-α-pinitol in vitro. Overexpression of DcTPSb1 in tobacco resulted in a significant increase in terpenoid release during the blooming stage; however, the up-regulated substances did not include their catalytic products. The classification of DcTPSb1 as a terpene synthase capable of producing multiple products provides valuable insights into the complex biosynthesis of terpenes in orchids. These findings enhance our understanding of the functional diversity of DcTPSb1 and the processes involved in terpene biosynthesis in orchids. Full article

Improving floral scent quality is an important goal in Malus breeding. However, the inheritance regularity for volatile components of Malus remains unclear. In this study, the floral scent compounds and scent characteristics of five Malus taxa with clearly defined parent–progeny relationships were analyzed by sensory evaluation, an electronic nose, and gas chromatography–mass spectrometry. A total of 51 volatile compounds were identified in five taxa. M. ioensis showed the highest sensory intensity with the maximum total content of compounds (8247.59 ng·g⁻¹ FW·h⁻¹). Compared to its progenies and ‘Lemoinei’, terpenoid compounds in M. ioensis accounted for the largest proportion (40.46%). Most compounds in the progenies were inherited from their maternal parent (60.61–75.00%), and most of them were significantly downregulated by hybridization. However, the content of several compounds in the progenies appeared transgressive, even unique. Progenies and their maternal parents exhibited similar sensory characteristics: earthy/woody, sweet, and rose. The content of characteristic compounds (geranylacetone, 6-methyl-5-hepten-2-one, 2-phenylethanol, α-ionone, β-ionone, decanal, and so on), total content, and the response of sensor W3S positively correlated with scent intensity. The response of sensor W1W correlated significantly and positively with the compound number and the total content. Our findings provided a reference for tracking maternal parents for cultivars and enabled rapid selection of fragrant flower cultivars by electronic nose. Full article

The calamondin (Citrus × microcarpa) is highly valued for its ornamental appeal and rich aromatic compounds, making it suitable for therapeutic gardens and widely applicable in the cosmetics, food, pharmaceutical, and perfume industries. Despite its importance, there is a lack of research on its floral volatiles. This study utilized headspace solid-phase microextraction gas chromatography–mass spectrometry (HS–SPME–GC–MS) to detect the volatile organic compounds (VOCs) of calamondin at different floral developmental stages: bud (BS), half-open (HS), full bloom (FS), and senescence (SS). Multivariate statistical analysis was employed to elucidate the aromatic characteristics. The results identified 67 VOCs across the four stages, including forty-eight terpenoids, six esters, five aromatics, four aldehydes, one olefin, one alcohol, and two others. Thirty-three VOCs were common across all stages, while BS, HS, FS, and SS had three, three, four, and nine unique VOCs, respectively. The total VOC content increased initially and then decreased as the flowers developed, with terpenoids being the predominant compounds, accounting for over 90% of the total emissions at all stages. Principal component analysis and hierarchical cluster analysis confirmed significant differences in VOC profiles at different stages. Partial least squares discriminant analysis identified five VOCs with variable importance in projection (VIP) values greater than one, including limonene, linalool, β-pinene, germacrene D, and β-ocimene, indicating their varying emission levels across stages. These findings enhance our understanding of the VOC characteristics of calamondin flowers and provide a scientific basis for further ornamental and industrial applications. Full article

This study utilized gas chromatography-mass spectrometry (GC-MS) to analyze the volatile components and sensory profiles of four basil varieties, both in their fresh state and as essential oils (EOs) extracted via steam distillation (SD). By employing headspace solid-phase microextraction (HS-SPME) and SD/GC-MS, a comprehensive comparison was conducted to elucidate the changes in volatile profiles before and after drying and extraction processes. In total, 47 volatile components were identified in fresh basil samples. Methyl chavicol was predominant in Thai basil (66.53%), lemon basil (90.18%), and sweet basil (89.19%), whereas linalool (58.56%) was the major component in purple basil. For EOs, 66 volatile components were detected, with methyl chavicol remaining significant in Thai basil (65.27%) and lemon basil (81.03%), though its proportion decreased in sweet basil (29.34%). Purple basil EOs showed a higher proportion of alcohols (54.54%) and terpenoids (31.31%), with the notable presence of linalool (20.08%) and τ-juniper alcohol (18.18%). Multivariate analyses, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), revealed significant variations in volatile profiles among basil varieties. Sensory evaluation, supported by radar fingerprinting, demonstrated that the drying and extraction processes notably impacted the aroma profiles. Distinctive aroma profiles revealed that Thai basil was noted for its aniseed aroma, lemon basil for its lemon scent, sweet basil for its pungency, and purple basil for its floral notes. These findings highlight the diverse applications of basil varieties and their EOs, providing valuable insights into flavoring, fragrance, and therapeutic products based on their volatile compositions and sensory attributes. Full article

Tea standard samples are the benchmark for tea product quality control. Understanding the inherent differences in Chinese national standards for Lapsang Souchong black tea of different grades is crucial for the scientific development of tea standardization work. In this study, Lapsang Souchong black tea of different grades that meet Chinese national standards was selected as the research object. The aroma characteristics were comprehensively analyzed through sensory evaluation, electronic nose, and HS-SPME-GC-MS (headspace solid-phase microextraction gas chromatography–mass spectrometry). The findings indicate that the higher-grade Lapsang Souchong has a higher evaluation score. The results of electronic nose analysis indicate that the volatiles with differences in tea of different grades were mainly terpenoids and nitrogen oxides. The results of HS-SPME-GC-MS analysis show that the odor characteristics of the super-grade samples are mainly floral and fruity, and these substances mainly include D-Limonene, 3,7-dimethyl-1,6-octadien-3-ol and 3-Hydroxymandelic acid, and ethyl ester. The primary aroma characteristics of the first-grade samples are floral, sweet, woody, and green, with key contributing compounds including 2-Furanmethanol, 1-Octen-3-ol, and 5-ethenyltetrahydro-α,α,5-trimethyl-cis-, 4,5-di-epi-aristolochene. The main aroma characteristics of the second-grade samples are green, herbal scent, and fruity, and the main substances include 3,7-dimethyl-1,6-octadien-3-ol, 2,3-dimethylthiophene, Dihydroactinidiolide, and Naphthalene-1-methyl-7-(1-methylethyl)-. It is worth noting that the second-grade samples contain a large amount of phenolic substances, which are related to the smoking process during processing. This study lays a solid foundation for the preparation of tea standard samples and the construction of the tea standard system. Full article

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. Full article

Keeving is the removal of nutrients from apple musts due to their binding to pectin, resulting in a slower fermentation and spontaneous arrest. The aim of this study was to determine the effect of keeving on the chemical composition of fermented apple must and on the volatile profile and sensory analysis of apple brandies. We compared the application of keeving during spontaneous fermentation with fermentation carried out by Saccharomyces cerevisiae (SafSpirit HG-1). We evaluated the impact of adding different doses of calcium chloride on various parameters of fermented musts and distillates. Calcium chloride had a greater effect on the ethanol concentration, total extract, and fermentation efficiency than on the type of fermentation used. However, a different phenomenon was observed with respect to the volatiles. The concentration of most of the higher alcohols, acetaldehyde, dodecanal, and geranylaceton, decreased after spontaneous fermentation and increased during the fermentation carried out with Saccharomyces cerevisiae SafSpirit HG-1. In general, the application of keeving contributed to a decrease in the concentration of ethyl and methyl esters, but caused an increase in the concentration of all acetate esters and terpenoids. When the amount of nutrients in the environment is limited and starvation occurs, microorganisms use the available nutrients for basic metabolic processes that allow them to survive and limit the formation of side metabolites such as volatiles. However, most of the samples fermented after the faecal depletion achieved high scores for the floral, fruity, and “overall note” parameters in the sensory analysis. This means that this method, carried out with a properly selected yeast strain, could be feasible for the distilling industry. Full article

Chestnut (Castanea mollissima) is an economically important forest tree species, and its flowers possess functions such as repelling mosquitoes, killing bacteria, and clearing heat. However, the regulatory mechanisms of floral volatile organic compounds (VOCs) in chestnut are still unclear. This study analyzed the contents of major volatile compounds and related gene expression levels in chestnut flowers during the initial flowering stage (IFS) and full-flowering stage (FFS) using metabolomics and transcription techniques. In total, 926 volatile compounds were detected, mainly terpenes, heterocyclic compounds, and esters. Acetylenone, styrene, and β-pinene had contents that exceeded 5% in FFS chestnut flowers. In total, 325 differential metabolites between the IFS and FFS were significantly (p < 0.05) enriched in the biosynthetic pathways of sesquiterpenes and triterpenes, as well as the ethylbenzene metabolic pathway. In total, 31 differentially expressed genes (DEGs) were related to terpenoid biosynthesis. There were only two DEGs related to the ethylbenzene metabolic pathway. In summary, we identified the volatile components of chestnut flowers and analyzed the changes in the contents of major volatile compounds in the flowers and the expression patterns of the related genes. The research results are helpful for understanding the regulation of VOCs in chestnut flowers. Full article

Rhododendron, a globally popular ornamental flower, is nevertheless limited in our understanding of the mechanisms underlying its fragrance formation. Notably, terpenoids are the most prevalent volatile metabolite produced by plants. In this study, gas chromatography–mass spectrometry (GC–MS), liquid chromatography–mass spectrometry (LC–MS) and transcriptomics sequencing were conducted to analyze the synthesis mechanisms of terpenoid fragrance compounds of petals in fragrant R. fortunei Lindl. (YJ) and non-fragrant R. “Nova Zembla” (NW). The results identified that (-)-myrtenol, linalool, pinene, myrtenyl acetate, and terpineol were key floral aroma substances in YJ. Furthermore, an analysis of KEGG enrichment and differentially expressed genes (DEGs) revealed that the bud and decay stages exhibited the highest number of enriched DEGs among different aroma types, indicating these as critical stages for the synthesis of terpenoid floral compounds. In this study, a structural gene, denoted as RfFDPS, was identified as a negative regulatory gene for monoterpene accumulation and a positive regulatory gene for sesquiterpene accumulation in YJ. Utilizing subcellular localization technology, we determined that RfFDPS proteins are located in the cytoplasm. A functional analysis through transient expression and gene silencing of RfFDPS demonstrated its ability to regulate the accumulation of monoterpenes and sesquiterpenes. The overexpression of RfFDPS led to an increase in the expression of structural genes related to terpenoid synthesis, resulting in a decrease in monoterpenes and an increase in sesquiterpenes. Conversely, gene silencing had the opposite effect. In conclusion, RfFDPS plays a pivotal role in the synthesis and release of terpenoid volatile compounds in YJ petals, laying a solid theoretical foundation for the cultivation and enhancement of aromatic R. species. Full article