Search Results (594)

The impact of seasonality on the aroma quality of tea has been documented in various tea types, but not specifically in oolong tea. This study is the first to explore the complex relationships between seasonality, volatile compounds, and aroma quality in oolong tea. Using Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS)-based untargeted metabolomics, we analyzed 266 samples of Tieguanyin oolong tea. The data identified linalool, linalool oxides (trans-linalool oxide (furanoid) and trans-linalool oxide (pyranoid)), and their metabolites (diendiol I; hotrienol) as key seasonal discriminants. Four out of the top ten key differential compounds for distinguishing aroma scores were metabolites from fatty acid degradation, namely trans-3-hexenyl butyrate, trans-2-hexenyl hexanoate, hexyl hexanoate, and hexyl 2-methyl butyrate. Approximately one-fifth of the seasonal discriminant volatile compounds were significant in influencing aroma quality. Overall, the impact of seasonality on the aroma quality of finished Tieguanyin oolong tea is marginal. These findings enhance our understanding of the interplay between seasonal variations, volatile composition, and aroma quality in oolong tea. Full article

Knowledge about the composition (volatile and non-volatile) and functionality of natural extracts from Mediterranean plants serves as a basis for their further application. In this study, five selected plants were used for the extraction of plant metabolites. Leaves and flowers of Critmum maritimum, Rosmarinus officinalis, Olea europea, Phylliera latifolia and Mellisa officinalis were collected, and a total of 12 extracts were prepared. Extractions were performed under microwave-assisted conditions, with two solvent types: water (W) and a hydroalcoholic (ethanolic) solution (HA). Detailed extract analysis was conducted. Phenolics were analyzed by detecting individual bioactive compounds using high-performance liquid chromatography and by calculating total phenolic and total flavonoid content through spectrophotometric analysis. Higher concentrations of total phenolics and total flavonoids were obtained in the hydroalcoholic extracts, with the significantly highest total phenolic and flavonoid values in the rosemary hydroalcoholic extract (3321.21 mg_GAE/L) and sea fennel flower extract (1794.63 mg_QE/L), respectively; and the lowest phenolics in the water extract of olive leaves (204.55 mg_GAE/L) and flavonoids in the water extracts of sea fennel leaves, rosemary, olive and mock privet (around 100 mg_QE/L). Volatile organic compounds (VOC) were detected using HS-SPME/GC–MS (Headspace Solid-Phase Microextraction coupled with Gas Chromatography-Mass Spectrometry), and antioxidant capacity was estimated using DPPH (2,2-diphenyl-1-picrylhydrazyl assay) and FRAP (Ferric Reducing Antioxidant Power) methods. HS-SPME/GC–MS analysis of samples revealed that sea fennel had more versatile profile, with the presence of 66 and 36 VOCs in W and HA sea fennel leaf extracts, 52 and 25 in W and HA sea fennel flower extracts, 57 in rosemary W and 40 in HA, 20 in olive leaf W and 9 in HA, 27 in W mock privet and 11 in HA, and 35 in lemon balm W and 10 in HA extract. The lowest values of chlorophyll a were observed in sea fennel leaves (2.52 mg/L) and rosemary (2.21 mg/L), and chlorophyll b was lowest in sea fennel leaf and flower (2.47 and 2.25 mg/L, respectively), while the highest was determined in olive (6.62 mg/L). Highest values for antioxidant activity, determined via the FRAP method, were obtained in the HA plant extracts (up to 11,216 mg_AAE/L for lemon balm), excluding the sea fennel leaf (2758 mg_AAE/L) and rosemary (2616 mg_AAE/L). Considering the application of these plants for fresh fish preservation, antimicrobial activity of water extracts was assessed against Vibrio fischeri JCM 18803, Vibrio alginolyticus 3050, Aeromonas hydrophila JCM 1027, Moraxella lacunata JCM 20914 and Yersinia ruckeri JCM 15110. No activity was observed against Y. ruckeri and P. aeruginosa, while the sea fennel leaf showed inhibition against V. fisheri (inhibition zone of 24 mm); sea fennel flower was active against M. lacunata (inhibition zone of 14.5 mm) and A. hydrophila (inhibition zone of 20 mm); and rosemary and lemon balm showed inhibition only against V. fisheri (inhibition zone from 18 to 30 mm). This study supports the preparation of natural extracts from Mediterranean plants using green technology, resulting in extracts rich in polyphenolics with strong antioxidant potential, but with no clear significant antimicrobial efficiency at the tested concentrations. Full article

The white oil-bearing rose (R. alba L.) is the second of the industrially important rose species for Bulgarian rose cultivation and essential oil production. In recent years, the interest in white oil-bearing rose has increased, following the worldwide trend for searching for new aromatic alternatives. Therefore, the purpose of the current research is to evaluate the volatile compounds profile of fresh R. alba L. flowers using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS). More than 75 individual compounds were identified and quantified using HS-SPME-GC/MS. The study revealed that the aroma-bearing fraction of rose volatiles consists mainly of monoterpene alcohols; 2-phenylethanol was the most abundant component (8.4–33.9%), followed by geraniol (12.8–32.5%) and citronellol + nerol (17.7–26.5%). Linalool, α-pinene, β-myrcene, and rose oxides were also observed in low concentrations. The stearopten fraction in the HS phase was observed in low concentration, with main representatives nonadecane + nonadecene, heptadecane, heneicosane, and tricosane. The HS-GC profile of the R. alba fresh flowers shows distinct differences in relative abundance of the components between the two studied clones of the population, as well as between volatiles in petals and in the whole blossom. The absence of some undesirable components, such as allergenic and potentially carcinogenic methyl eugenol in fresh R. alba blossom, makes white oil-bearing rose a promising alternative to R. damascena in perfumery, natural cosmetics, and aromatherapy. Full article

Tomatoes are globally esteemed not only for their nutritional value but also for their complex and appealing aroma, a key determinant of consumer preference. The present study aimed to comprehensively characterise the volatilomic fingerprints of three tomato species—Solanum lycopersicum L., S. lycopersicum var. cerasiforme, and S. betaceum—encompassing six distinct varieties, through the application of headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS). A total of 55 volatile organic compounds (VOCs) spanning multiple chemical classes were identified, of which only 28 were ubiquitously present across all varieties examined. Carbonyl compounds constituted the predominant chemical family, with hexanal and (E)-2-hexenal emerging as putative key contributors to the characteristic green and fresh olfactory notes. Notably, esters were found to dominate the unique volatile fingerprint of cherry tomatoes, particularly methyl 2-hydroxybenzoate, while Kumato and Roma varieties exhibited elevated levels of furanic compounds. Multivariate statistical analyses, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), demonstrated clear varietal discrimination and identified potential aroma-associated biomarkers such as phenylethyl alcohol, 3-methyl-1-butanol, hexanal, (E)-2-octenal, (E)-2-nonenal, and heptanal. Collectively, these findings underscore the utility of volatilomic fingerprint as a robust tool for varietal identification and quality control within the food industry. Full article

The sensory quality of black tea is intrinsically linked to cultivar genetics, yet comprehensive characterization of flavor compounds in emerging northern Guangdong black tea (NGBT) remains limited. This study employed high-performance liquid chromatography-ultraviolet (HPLC-UV) and headspace solid-phase microextraction coupled with GC-MS (HS-SPME-GC-MS) to analyze non-volatile and volatile compounds in five NGBT cultivars—Jinshahong (JSH), Danxia No.1 (DXY), Danxia No.2 (DXE), Yingde Black Tea (QTZ), and Yinghong No.9 (YHJ)—alongside sensory evaluation. Orthogonal partial least squares-discriminant analysis (OPLS-DA) identified key non-volatile discriminants (VIP > 1) ranked by contribution: total catechins > simple catechins > CG > EGCG > ester catechins > EGC. HS-SPME-GC-MS detected 97 volatiles, with eight aroma-active compounds exhibiting OAV > 1 and VIP > 1: Geraniol > Methyl salicylate > Linalool > β-Myrcene > Benzyl alcohol > (Z)-Linalool Oxide > Phenethyl alcohol > (Z)-Jasmone. These compounds drive cultivar-specific aromas in NGBTs. Findings establish a theoretical framework for evaluating cultivar-driven flavor quality and provide novel insights for targeted breeding and processing optimization of NGBTs. Full article

Essential oils have emerged as promising alternatives for pest insect control. However, sublethal effects on insect reproduction and development are rarely explored, despite their relevance to integrated pest management (IPM). This study evaluated the sublethal effects of Piper hispidivervum C. DC. essential oil (EOPH) on the development and population growth of four populations of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), as well as the persistence of safrole residue in treated corn grains. Population development rates were determined using emergence curves and total emerged adults, while population growth was assessed by counting live insects in the feeding substrate at different storage intervals. Safrole residue persistence was analyzed using solid-phase microextraction in headspace mode (SPME-HS). Sublethal exposure to EOPH significantly reduced the development rate, total emergence, and growth in three of the four populations. The population from Crixás, GO, showed no significant reduction, with a population curve overlapping the control. The lethal dose was reduced by 98.20%, indicating low persistence and potential food safety. The EOPH exhibited sublethal effects on S. zeamais populations, reducing both development rates and population growth. This reduction varied among the populations studied. Further research is encouraged to explore its effects on different insect populations and under broader environmental conditions. Full article

The garden Nasturtium (Tropaeolum majus L.) is increasingly consumed worldwide due to its culinary appeal and perceived health benefits. However, the chemical markers underlying its functional properties remain insufficiently characterized. Building on evidence from a recent human pilot study confirming both high acceptability and dietary safety, we conducted a comprehensive volatilomic and phytochemical analysis of T. majus flowers and their juice. Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS) was employed to establish the volatilomic fingerprint of floral tissues and juice. Our analysis revealed a striking dominance of benzyl isothiocyanate and benzonitrile, which together accounted for 88% of the total volatile organic metabolites (VOMs) in the juice, 67% and 21%, respectively. In the floral tissues, benzyl isothiocyanate was even more prevalent, representing 95% of the total volatile profile. Complementary in vitro assays confirmed a substantial total phenolic content and strong antioxidant activity in the flowers. These findings provide a robust chemical rationale for the potential health-promoting attributes of T. majus, while identifying key volatilomic markers that could support future functional and safety claims. In parallel, a benefit–risk assessment framework is discussed in accordance with the European Food Safety Authority (EFSA) guidelines for the Qualified Presumption of Safety (QPS) of edible flowers. Given that both benzyl isothiocyanate and benzonitrile are classified as Cramer Class III substances, a conservative intake threshold of 1.5 μg/kg body weight per day is proposed. To enable quantitative exposure modeling and support the derivation of a tolerable daily intake (TDI), future studies should integrate organic solvent-based extraction methodologies to estimate the total volatile load per gram of floral biomass. This would align risk–benefit assessments with the EFSA’s evolving framework for novel foods and functional ingredients. Full article

Wuyi Shuixian tea, a premium oolong tea known for its complex floral-fruity aroma, exhibits significant quality variations across different grades. This study systematically analyzed the aroma characteristics and key fragrant compounds of four grades (Grand Prize SA, First Prize SB, Outstanding Award SC, and Non-award SD) using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV) analysis, and multivariate statistical methods. A total of 159 volatile compounds were identified, with similar compound categories but distinct concentration gradients between grades. OAV-splitting analysis (based on OAV ≥ 1 as the threshold for aroma activity) identified β-ionone (fruity), octanal (fatty), and linalool (floral) as core aroma-active contributors, as their OAV values significantly exceeded 10 in awarded grades (SA, SB, SC), indicating dominant roles in sensory perception. Notably, linalool, a floral marker, showed a concentration gradient (SA > SB > SC) and was absent in SD, serving as a critical determinant of grade differentiation. Orthogonal partial least squares-discriminant analysis (OPLS-DA) further distinguished awarded grades (SA, SB, SC) by balanced fruity, floral, and woody notes, while SD lacked floral traits and exhibited burnt aromas. This classification was supported by hierarchical clustering analysis (HCA) of volatile profiles and principal component analysis (PCA). Electronic nose data validated these findings, showing strong correlations between sensor responses (W5S/W2W) and key compounds like hexanal and β-ionone. This study elucidates the molecular basis of aroma-driven quality grading in Wuyi Shuixian tea, providing a scientific framework for optimizing processing techniques and enhancing quality evaluation standards. The integration of chemical profiling with sensory attributes advances precision in tea industry practices, bridging traditional grading with objective analytical metrics. Full article

In this study, we analysed cocoa (a dried and fully fermented seed of Theobroma cacao L.) from two Amazonian cultivars and a commercial sample of the Amazonian variety EETP801, grown under sustainable organic conditions, in comparison to CCN51 cocoa grown on a neighbouring commercial farm using standard practises and a European commercial cacao powdered beverage. The overall metabolite profile of the 70% aq acetone sample cocoa extracts was analysed using high-performance TLC analyses (HPTLC), and the xanthine alkaloids were analysed using quantitative liquid chromatography–UV photodiode array (HPLC-DAD) analyses. The volatile fraction in the headspace of the freshly ground cocoa was subjected to solid phase micro-extraction and analysed by gas chromatography–mass spectrometry (HS-SPME/GC-MS). Total polyphenol content was determined by the Folin–Ciocalteu method. Despite the reduced production of cocoa by the EETP801 cultivar in comparison with the CCN51 cultivar, the obtained produce is significantly richer in theobromine (130 mg vs. 170 mg per g of cacao), with CCN51 having a double concentration of theophylline (12.6 vs. 6.5 mg per g of cacao). Qualitatively, the two Amazonian cocoa samples had a similar polyphenolic composition (per the HPTLC fingerprint). HS-SPME/GC-MS analyses revealed that all the samples show a spontaneous emission profile mainly rich in non-terpene derivatives, of which hydrocarbons and pyrazines are the most abundant groups. The most represented volatile organic compound is n-tridecane for both EETP801 and CCN51. The variability in the artisan fermentation and roasting processes influenced certain aspects of the volatile composition as reflected by the trimethyl pyrazine/tetramethyl pyrazine ratio, which was zero in EETP-801 and lower than 1 in CCN51. Acetic acid was absent in CCN51 but significant (c.a. 5.5.%) in EETP801 and the commercial samples. The cultivar EETP801 is a viable option for a more ecologically conscious sector of the cocoa beverages consumer group. Full article

Various volatile compounds are responsible for the odor changes in fish during storage. In this study, a coupled headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC-MS) analytical approach was applied to characterize the volatile compounds in large yellow croaker (Pseudosciaena crocea) during storage under three treatments: cold storage (CS), slurry ice (SI), and crushed ice (CI). A total of 24 volatile substances were identified, including aldehydes, ketones, and alcohols. Multivariate statistical analyses (PCA, PLS-DA, VIP, and cluster heatmap) revealed significant differences in volatile compounds between the treatment groups during storage, and 10 key volatiles along with 5 potential biomarker compounds were identified. The underlying mechanisms of volatile changes were further investigated by analyzing three key pathways: thermal reactions, lipid oxidation, and amino acid degradation. Notably, SI treatment better avoid volatile compound variation in large yellow croaker. Full article

The exploitation of underutilised resources is critical for achieving a sustainable society, and non-edible seaweeds are promising candidates. This study focused on the red alga Portieria hornemannii from Okinawa, Japan, a seaweed with a distinctive aroma, and determined its volatile organic compounds (VOCs) and halogenated secondary metabolites using headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS) at various extraction temperatures. HS-SPME-GC-MS analysis revealed 52 VOCs in Okinawan P. hornemannii, including predominant compounds α-pinenyl bromide (IUPAC name: 2-bromomethyl-6,6-dimethylbicyclo [3.1.1]hept-2-ene; halogenated monoterpene), myrcene disulfide (3-(6-methyl-2-methylidenehept-5-enylidene)dithiirane), and 5,6-dimethyl-1H-benzimidazole, the content of which in the extract increased with increasing extraction temperature from 30 to 60 °C. On the other hand, the β-myrcene (7-methyl-3-methyleneocta-1,6-diene) content, which likely contributes majorly to the distinct fresh odour of the algae, declined as the temperature increased. Furthermore, the proportion of β-myrcene obtained using SPME was significantly higher than that extracted using solvent liquid extraction (SLE) (7.20% in SPME at 30 °C vs. 0.09%, respectively). However, SLE-GC-MS provided a different P. hornemannii volatile profile, allowing for the acquisition of more furan-, alcohol-, ester-, and carboxylic acid-containing compounds. These data provide valuable information, such as a systematic analytical framework for volatiles profiling in the marine macroalgae P. hornemannii, with potential applicability in the development of food and fragrance products. Full article

The evaluation of region-specific aroma characteristics in green tea remains critical for quality control. This study systematically analyzed eight Tongcheng Xiaohua tea samples (standard and premium batches) originating from four distinct regions using sensory analysis, electronic nose (E-nose), headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), and chemometrics. The E-nose results demonstrated that the volatile characteristics of Tongcheng Xiaohua tea exhibit distinct geographical signatures, confirming the regional specificity of its aroma. HS-SPME-GC-MS identified 66 volatile metabolites across samples, with 18 key odorants (OAV > 1) including linalool, geraniol, (Z)-jasmone, and β-ionone driving aroma profiles. The partial least squares–discriminant analysis (PLS-DA) model, combined with variable importance in projection (VIP) scores and OAV, identified seven compounds that effectively differentiate the origins, among which α-pinene and β-cyclocitral emerged as novel markers imparting unique regional characteristics. Further comparative analysis between standard and premium grades revealed 2-methyl butanal, 3-methyl butanal, and dimethyl sulfide as main differential metabolites. Notably, the influence of geographical origin on metabolite profiles was found to be more significant than batch effects. These findings establish a robust analytical framework for origin traceability, quality standardization, and flavor optimization in tea production, providing valuable insights for the tea industry. Full article

The increasing scarcity of traditional nectar sources due to climate change has led beekeepers to explore alternative floral sources. This study investigates the volatile profile, sensory characteristics, and consumer acceptability of monofloral honey derived from Capparis spinosa L., a drought-resistant Mediterranean plant. Honey samples produced by Apis mellifera ssp. sicula on Aeolian Islands (Sicily, Italy) were analyzed. Volatile organic compounds (VOCs) were extracted using headspace solid–phase microextraction (HS-SPME) and identified by gas chromatography–mass spectrometry (GC–MS), revealing 59 compounds, with dimethyl sulfide being the predominant one. Sensory evaluation using quantitative descriptive analysis (QDA) and Time Intensity (TI) analysis identified distinctive descriptors such as sweet-caramel, cabbage/cauliflower, and pungent notes. Statistical analyses confirmed correlations between specific VOCs and sensory perceptions. A consumer acceptability test involving 80 participants showed lower preference scores for caper honey in terms of aroma and overall acceptability compared to commercial multifloral honey, with differences observed across age groups. The unique aromatic profile and consumer feedback suggest that caper honey has strong potential as a niche, high-quality product, particularly within the context of climate-resilient beekeeping, offering valuable opportunities for innovation and diversification in sustainable apiculture. Full article

The development of sensitive, non-invasive methods is essential for the preservation and study of heritage books, allowing insights into their historical production processes and conservation needs. Volatile organic compound (VOC) analysis provides a valuable, non-destructive approach to assess paper composition and degradation in historical volumes. In this study, we analyzed VOC emissions from two books preserved at the Biblioteca Capitolare of Busto Arsizio, Italy: a 16th-century Latin grammar book and a 19th-century mathematics handbook for measurement conversions. Using headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC-MS), VOCs were sampled after 24 h of storage at room temperature. The results revealed distinct degradation markers: Straight-chain aldehydes, indicative of lipid oxidation, were more prevalent in the 16th-century book, reflecting the higher quality and durability of its rag-based paper. In contrast, elevated furfural levels in the 19th-century book suggest accelerated cellulose hydrolysis typical of wood pulp paper. Additionally, the presence of menthol and anethole in both volumes points to the use of bacteriostatic agents for preservation. These findings not only highlight differences in material composition but also underscore the importance of tailored conservation approaches for historical documents from different eras. Full article

This study investigates the impact of using Lactiplantibacillus plantarum and Saccharomyces cerevisiae, either individually or in co-culture, on the fermentation of rose beverage. We comprehensively analyzed the resulting changes in quality characteristics and volatile compound profiles. Fermentation significantly altered the physicochemical properties, appearance, color, and free amino acid/organic acid content. Both microbial strains significantly increased total polyphenols and flavonoid content, with co-fermentation exhibiting a more pronounced effect compared to single-strain fermentations. Furthermore, the volatile compounds in rose beverages fermented with different microorganisms were characterized by an electronic nose (E-nose) and headspace–solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS). E-nose analysis demonstrated distinct volatile profiles distinguishing the four fermentation samples. HS-SPME/GC-MS identified a total of 245 volatile compounds, among which alcohols constituted the most abundant class. Integrating GC-MS data with odor activity value (OAV ≥ 1) analysis pinpointed 34 key aroma compounds. Partial least-squares discriminant analysis (PLS-DA) based on variable importance in projection (VIP) identified eight key volatile markers: eugenol, phenylethyl alcohol, (E)-3,7-dimethyl-2,6-octadienoic acid, methyleugenol, ethyl octanoate, citronellol, D-citronellol, and 2,4-bis(1,1-dimethylethyl)phenol. These findings provide valuable insights into the microbial influence on rose beverage quality and offer a theoretical basis for optimizing industrial fermentation processes. Full article