Search Results (128)

To elucidate the impacts of climatic and edaphic factors on the chemical composition and bioactivities of black mulberries, this study conducted a systematic comparative analysis of fruits sourced from four regions in Xinjiang: Turpan (T), Bayingolin Mongol Autonomous Prefecture (B), Hotan (H), and Kashgar (K). H exhibited the highest contents of total phenolics and total tannins, whereas T showed elevated levels of total flavonoids and flavan-3-ols. Notably, samples from B and H demonstrated superior antioxidant potential. Using UPLC-MS/MS, a total of 48 anthocyanin metabolites and 4 non-anthocyanin metabolites were identified in the mulberry fruits. Among these, 6 were region-specific compounds, and 8 were identified as differential metabolites. Furthermore, headspace solid-phase microextraction (HS-SPME) coupled with GC-MS/MS revealed 292 volatile metabolites, of which 15 were identified as differential metabolites based on OPLS-DA and relative odor activity value (rOAV) analyses. Metabolite profiling indicated that B possessed the greatest diversity of volatile metabolites, while T exhibited a remarkable richness in anthocyanin diversity. The observed regional variations in chemical constituents and metabolite profiles collectively accounted for the differences in antioxidant capacity and enzyme inhibitory activities among the black mulberry fruits. These findings provide a theoretical foundation for the regional characterization and targeted processing of black mulberries from the four production areas in Xinjiang. Full article

Quality deterioration, characterized by browning and cooked-off flavor (COF) development, often occurs in green tea beverages (GTBs) during shelf life. Changes in sensory quality and physical and chemical properties, as well as COF formation and its alleviation under different storage conditions, were comprehensively investigated in beverages prepared from five green teas and one jasmine-scented green tea. As the storage temperature increased and the storage duration extended, all GTBs exhibited a noticeable decrease in total sensory score (TSS), along with remarkable increases in total color difference (ΔE) and COF. Contents of total polyphenols declined markedly during storage of GTBs, while levels of caffeine and free amino acids changed insignificantly. Among the nine volatiles negatively correlated with TSS and positively correlated with COF, linalool, geraniol, 1-octanol, and 3-methylbutanal were identified as key COF contributors due to their high relative odor activity values. These results indicate that quality deterioration of GTBs during storage is closely associated with polyphenol loss, accumulation of COF-related components, and shifts in volatile composition and ratios. Notably, beverages prepared from jasmine-scented tea exhibited higher sensory scores and slower quality deterioration during storage than those prepared from unscented tea. This study identifies the key volatile contributors to COF and demonstrates that jasmine scenting effectively mitigates quality deterioration, offering a practical strategy for extending the shelf life of GTBs. Full article

Yunnan traditional rose jam is made from fresh Rosa ‘Crimson Glory’ petals and brown sugar through natural fermentation and has been consumed by local people for years due to its characteristic floral aroma. The present study investigated the dynamics and correlations between the microbial communities and flavor quality during 98-day fermentation at ambient temperature (23.72 ± 1.26 °C). The total titratable acidity (0.20–0.29 g/100 g) and reducing sugars content (0.92–5.37 g/100 g) increased with fermentation, while the pH (4.30–5.47), total phenolics content (0.25–0.72 g/100 g), and total flavonoids content (0.13–0.32 g/100 g) decreased. High-throughput 16S rDNA and ITS sequencing revealed that Klebsiella, Zygosaccharomyces, Starmerella, and Podosphaera were the dominant microorganisms. Esters and terpenoids were the main flavor substances. Based on relative odor activity value evaluation, the relative levels of volatile compounds responsible for rose, sweet, and fruity odors increased during fermentation, while those responsible for a green character diminished. The physicochemical properties, especially the total titratable acidity and reducing sugars, as well as esters and terpenoids were positively related with Zygosaccharomyces. The present study systematically elucidated the correlation between microbial communities and flavor formation during fermentation of Yunnan traditional rose jam, providing key scientific basis for flavor-targeted regulation and standardized production of this traditional fermented food. Full article

This study explored the flavor profiling of baked potatoes, with a focus on how maturity affects the volatile flavor. By using HS-SPME-GC-MS, sensory evaluation, multivariate statistical analysis and computational modeling, a total of 99 volatile compounds were finally identified. Multivariate statistical analysis yielded 36 different important compounds (VIP > 1, p < 0.05). Subsequently, combined with relative odor activity value (ROAV), four key compounds including 2-ethyl-3,5-dimethylpyrazine, 2,6-diethylpyrazine, ethyl acetate and benzeneacetaldehyde were identified as potential indicators of baked potatoes with different maturities. Further, molecular docking analysis revealed the interactions between key pyrazine compounds and human olfactory receptors OR5K1 through hydrogen bonds and other interactions. These findings provide new insights into the relationship between potato maturity and flavor differences, and also lays a foundation for in-depth exploration into flavor identification and perception. Full article

Four sweet cherry cultivars (FuChen, Redlight, Huangmi, and Samituo) grown in northern China were used to produce sweet cherry wines with two alcohol levels. Physicochemical properties, antioxidant capacity, and volatile aroma compounds of the wines were systematically investigated. The results showed that wine from the Redlight cultivar with an alcohol content of 11.22 ± 0.17% contained the highest phenolic content and also exhibited the strongest antioxidant capacity as measured by DPPH and ABTS•⁺ assays. Meanwhile, wine from the FuChen cultivar with an alcohol content of 11.45 ± 0.03% had the highest anthocyanin content and showed the strongest FRAP antioxidant activity. Orthogonal partial least squares discriminant analysis (OPLS-DA) based on electronic nose data clearly distinguished the eight sweet cherry wine samples from different cultivars. A total of 58 volatile compounds were identified by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS). Both principal component analysis (PCA) and OPLS-DA revealed clear differences among the sweet cherry wines based on their volatile composition. Using variable importance in projection (VIP) scores > 1 and relative odor activity values (ROAVs), the key aroma compounds contributing to the characteristic aroma profiles of the eight sweet cherry wines were identified as ethyl butanoate, isoamyl acetate, isoamyl hexanoate, methyl decanoate, ethyl decanoate, ethyl benzoate, methyl salicylate, citronellol, and eugenol. These findings provide important guidance for the selection of raw materials to improve the production of sweet cherry wines with targeted alcohol levels. Full article

This study presents a comprehensive flavour profile analysis of 12 Morchella samples (5 cultivated and 7 wild species) collected from diverse regions across China. The contents of free amino acids and volatile organic compounds were determined using UHPLC-QE-HRMS and HS-SPME-GC-MS. Flavour contribution was assessed by calculating taste activity values (TAVs) and relative odor activity values (rOAVs), and the influence of environmental factors on flavour compound accumulation was further explored. The findings indicated that cultivated Morchella exhibited pronounced fruity, floral, sweet, and mushroom-like notes (e.g., 1-octen-3-one, beta-damascone, and 1-(2-aminophenyl)ethanone), rendering them suitable for fresh consumption. In contrast, wild Morchella exhibited higher levels of herbaceous and smoky aroma compounds (e.g., (E,Z)-2,6-nonadienal, benzenemethanethiol, and non-8-enal), suggesting potential for premium product development. Correlation analysis revealed metabolic associations between taste-active amino acids and key volatile organic compounds via intermediates of the lipoxygenase pathway and the tricarboxylic acid cycle. Furthermore, environmental parameters including elevation, annual precipitation, and solar radiation were found to significantly influence the accumulation of flavour-related metabolites. These findings provide insights into the chemical basis underlying the flavour diversity of Morchella and offer a theoretical foundation for species identification, flavour-directed breeding, and differentiated product development. Full article

To reveal how the characteristic flavor of jasmine tea is generated, this study analyzed the coordinated changes in sensory properties, chemical components, and aroma migration behavior during scenting. Sensory evaluation, biochemical assays, and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) integrated with orthogonal partial least squares discriminant analysis (OPLS-DA) and relative odor activity value (rOAV) filtering were applied to tea samples before and after scenting. After scenting, aroma and taste scores increased significantly, and liquor color shifted from tender green to pale yellow. Amino acids and soluble sugars increased, while astringent substances such as tea polyphenols and catechins decreased. Key floral compounds, including cis-3-hexenyl benzoate and methyl anthranilate, were transferred from jasmine flowers to the tea base and enriched, likely contributing to the typical aroma profile. The retention rate of aroma in spent flowers was positively correlated with hydrophobicity (logP, r > 0.46, p < 0.01) and negatively with polarity (TPSA, r > −0.42, p < 0.05), suggesting regulation by hydrophobic partitioning. In contrast, aroma transfer to the tea base showed no simple correlation with any single physicochemical parameter, suggesting multi-factor regulation. This study provides insights into the scenting process and offers a theoretical reference for quality control in jasmine tea production. Full article

The sensory quality and flavor of lamb meat, critical to market competitiveness, are influenced by rumen microbial fermentation and dietary management strategies. Coated betaine (CBet), a rumen-protected methyl donor, exerts systemic nutritional regulation in ruminants. This study explored the effects of CBet supplementation on lamb meat quality using 18 Dorset ♂ × Hu sheep ♀ F1 crossbred lambs, randomly assigned to either a control group (basal diet) or a 0.20% CBet-supplemented diet for 60 days (n = 9 per group). The results demonstrated that CBet significantly increased ruminal concentrations of total volatile fatty acids (TVFAs), acetic acid, propionic acid, and butyric acid (p < 0.05). Additionally, CBet supplementation enhanced muscle redness (a*), crude fat, crude ash, heptadecanoic acid (C17:0), and tricosanoic acid (C23:0) (p < 0.05) while decreasing shear force and the concentration of cis-13,16-docosadienoic acid (C22:2) (p < 0.05). Furthermore, CBet elevated characteristic flavor compounds (e.g., nonanal) and their relative odor activity values (ROAVs), and decreased undesirable odors (e.g., dodecanal) (p < 0.05). As illustrated in the graphical abstract, these improvements were mediated through regulatory effects of CBet on rumen microbiota composition, muscle fatty acids, amino acids, and volatile flavor compounds. Specifically, CBet significantly increased the relative abundances of Firmicutes, Proteobacteria, Prevotella, and Bifidobacterium in the rumen (p < 0.05) and altered the Firmicutes/Bacteroidota ratio. In conclusion, dietary supplementation with 0.20% CBet effectively enhances lamb meat quality and flavor, effects closely associated with changes in the abundance of key ruminal microbial taxa. Full article

Ripened Pu-erh tea (RPT) experiences notable aroma transformations during industrial pile fermentation, yet the stage-dependent evolution of key aroma compounds remains poorly understood. This study analyzed two independent industrial batches of RPT across three fermentation stages: raw material (RM), intermediate fermentation (IF), and final fermentation (FF). Using HS-SPME/GC-MS coupled with multivariate statistical analysis and relative odor activity values (rOAVs), 134 volatile organic compounds (VOCs) were identified, with hydrocarbons, alcohols, and esters as predominant classes. In total, 13 key aroma-active compounds (rOAVs > 1) were found to be major contributors to RPT’s characteristic aroma. During early fermentation, relative levels of VOCs responsible for fresh and green aromas (e.g., linalool, D-limonene) diminished, while those for woody and minty aromas (e.g., isophorone, methyl salicylate) increased. A flavor wheel was developed to illustrate the dynamic shifts in aroma profiles. This stage-resolved analysis offers new mechanistic insights into aroma formation, aiding in the optimization of aroma quality control and process standardization for RPT production. Full article

This study developed an optimized processing strategy for γ-aminobutyric acid (GABA) instant white tea (GABA-IT) using GABA-enriched white tea as raw material, systematically characterizing its chemical composition and volatile profile. In contrast to the conventional instant tea production process, this work integrates response surface methodology with spray-drying parameter optimization. This integrated approach enables the simultaneous enhancement of functional components and sensory quality. A response surface design was employed to refine the extraction and spray-drying variables following preliminary single-factor trials, and the optimal parameter combination was subsequently determined (40% ethanol concentration, material-to-liquid ratio of 1:15, extraction time of 3 days, atomization speed of 300 rpm, and inlet temperature of 120 °C); the resulting GABA-IT exhibited significantly improved quality characteristics. Specifically, the GABA content increased by 209% (reaching 4.42 mg/g), and theanine, catechins, and caffeine were enriched by 200–300%. Regarding volatile profiles, processing led to a reduction in esters but an increase in aldehydes and hydrocarbons. Relative odor activity value (rOAV) analysis revealed that epoxy-β-ionone and linalool were the key contributors to the characteristic aroma of GABA-IT. Collectively, this study demonstrates the technical feasibility of producing GABA-rich instant tea with enhanced functional components and improved sensory quality, providing practical guidance for the large-scale industrial production of functional tea beverages. Full article

Consumer demand is growing for traceable, high-quality Cinnamomum cassia with defined sensory attributes. However, research linking cultivar morphology to these specific flavor signatures remains scarce. This study elucidated the relationships between phenotypic traits, volatile constituents, and key aroma characteristics of three C. cassia cultivars (Xijiang [XJ], Dongxing [DX], and Qinghua [QH]) using phenotypic evaluation, headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS), and a combination of relative odor activity value and principal component analysis (rOAV-PCA). XJ exhibited an intensely spicy aroma, attributable to its high trans-cinnamaldehyde content (718.76 ± 60.08 mg/g). In contrast, DX showed the highest δ-cadinene level (44.86 ± 4.48 mg/g) and a complex spicy–woody–sweet profile, shaped by sesquiterpenes such as α-humulene, α-copaene, caryophyllene, and β-caryophyllene. QH displayed both a high volatile oil yield (2.57 ± 0.28%) and a distinct herbal–woody character, primarily contributed by δ-cadinene and α-muurolene. This study constructed an integrated phenotype–chemistry–sensory map for C. cassia cultivars, facilitating cultivar discrimination, supporting flavor quality management, and enabling marker-assisted breeding for desirable aroma profiles. Full article

Given the growing consumer preference for plant-based proteins, improving their flavor profiles is essential for market success. Despite their nutritional benefits, plant proteins, such as walnut proteins, often suffer from weaker and less appealing flavors than those of animal proteins. This study investigated the pivotal role of amino acids in walnut aroma development during microwave treatment. Through gas chromatography mass spectrometry analysis of five walnut varieties, considerable differences in the aroma compound composition were identified with 13 key aroma components highlighted via relative odor activity value analysis. The present results demonstrated that methionine played a predominant role in pyrazine and heterocyclic compound production, underscoring its importance in walnut aroma formation. Thus, heat treatments, particularly microwave processing, show potential for enhancing flavor under the conditions investigated. These findings suggest a possible approach for improving flavor profiles in plant protein–based systems. Full article

In Chinese cuisine, seasoning oil enhances the aroma and appearance of dishes. This study examined how processing affects flavor release in multi-ingredient oils. Volatile organic compounds (VOCs), relative odor activity value (ROAV), and variable importance projection (VIP) were used to assess flavor changes. Optimal frying was 160 °C for 15 min with 11% green Sichuan peppercorn, 3% ghost pepper, 6% green onion, 0.1% bay leaf, 0.2% deseeded tsaoko, 0.5% star anise, 0.3% fennel seeds, 1.5% dried Erjingtiao chili, 5% ginger, and 2.5% red Sichuan peppercorn. Gas chromatography–ion mobility spectrometry (GC-IMS) and gas chromatography–mass spectrometry (GC-MS) analyzed heating at 150 °C, 160 °C, and 170 °C. Temperature strongly influenced VOC formation; 160 °C produced the most diverse VOCs, including aldehydes, ketones, terpenes, esters, and alcohols. Multivariate analysis identified 73 key compounds (VIP > 1) between 150 and 160 °C, but only 39 between 160 and 170 °C, indicating that high heat reduces complexity. Compounds such as 2-methylpyrazine and (E)-2-heptenal contributed caramel, nutty, buttery notes, with 2-methoxy-3-(1-methylethyl)-pyrazine as the core aroma. Frying at 160 °C balanced sweet, floral, and roasted aromas, offering guidance for precise seasoning oil flavor control. Full article

Grade and cultivar are the important factors influencing white tea quality, but their relative metabolic contributions are not fully understood. Twelve white tea samples representing four major Fujian cultivars across three grades were analyzed using UHPLC–MS-based non-volatile metabolomics, HS-SPME–GC–MS volatile profiling, and sensory correlation analysis. In total, 47 non-volatile and 21 volatile markers were associated with grade differences, while 44 non-volatile and 26 volatile markers were linked to cultivar differences. Catechins and amino acids declined as grade decreased, whereas flavonol glycosides and gallic acid increased, accompanied by stronger astringency and reduced umami and sweetness. Aroma profiles showed a similar trend, with higher-grade teas dominated by floral notes and lower-grade teas exhibiting more herbal characteristics. Dimeric catechins, oxylipins, and aroma glycosides varied among cultivars. Volatile profiles separated the cultivars into two aroma groups: Fuding Dabai and Fuding Dahao showed more floral–fruity aromas, whereas Fuan Dabai and Zhenghe Dabai exhibited stronger herbal and aged aromas. Odor activity value analysis showed that linalool, geraniol, and (E,Z)-3,6-nonadien-1-ol were among the most abundant aroma-active compounds across white tea samples. These results provide chemical evidence for distinguishing white tea by grade and cultivar, with potential relevance to quality evaluation. Full article

Hawk tea (Litsea coreana Levl. var. lanuginosa), a naturally caffeine-free herbal beverage widely consumed in Southwest China, is characterized by a pronounced camphoraceous note that often deters first-time consumers. In this study, hawk tea leaves were subjected to solid-state fermentation with four microbial strains—Monascus purpureus, Aspergillus cristatus, Bacillus subtilis, and Blastobotrys adeninivorans. The volatile compounds of unfermented and fermented hawk teas were identified by ultra-fast gas chromatography electronic nose (ultra-fast GC e-nose), gas chromatography–mass spectrometry (GC-MS) and gas chromatography–ion mobility spectrometry (GC-IMS) analyses, respectively. Furthermore, the calculation of odor activity values (OAVs) and relative odor activity value (ROAV) revealed that 6 and 25 volatile chemicals, including perillaldehyde (OAV 3.692) and linalool (ROAV 100), were the main contributors to the floral, fruity, and woody aroma of fermented hawk tea. Sensory evaluation confirmed that fermentation generally enhanced woody notes while significantly reducing the characteristic camphoraceous and oil oxidation odors. Notably, the Blastobotrys adeninivorans-fermented sample exhibited the most pronounced floral and fruity nuances, accompanied by significantly elevated aroma complexity and acceptability. Consequently, Blastobotrys adeninivorans represents a promising starter culture for the improvement of hawk tea flavor. Full article