Search Results (378)

Drying and storage conditions play a critical role in shaping the quality of aged citrus peel. This study investigated the effects of different processing strategies on the volatile composition, microstructure, and sensory characteristics of five-year-aged Citrus Reticulata ‘Chachi’ Peel (CRP). Four treatments were evaluated using SPME/GC–MS, GC–IMS, electronic nose analysis, sensory assessment, scanning electron microscopy (SEM), and multivariate statistical tools. GC–IMS identified 96 volatile compounds, demonstrating that aging combined with varied drying–storage conditions promoted the formation of diverse aroma-active substances. Terpenes and related compounds predominated, with the indoor-dried and warehouse-stored XH sample showing significantly higher concentrations of key terpenoids and sesquiterpenes, including α-terpineol, γ-muurolene, germacrene, β-selinenol, α-farnesene, and nerolidol. These compounds contributed to enhanced citrus, floral, fruity, and woody notes. Principal component analysis of electronic nose data (93.46% cumulative variance) clearly distinguished XH from other samples. Sensory results supported instrumental findings, indicating stronger fruity and sweet attributes in XH and C, while sun-dried samples exhibited more hay-like characteristics. SEM revealed better structural integrity in indoor-dried samples, potentially facilitating volatile retention. Overall, indoor drying and controlled storage improved aroma complexity and sensory quality, providing a scientific basis for optimized CRP processing. Full article

To explore the characteristic volatile compounds of ‘Hujing Milu’ peaches from different growing regions, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) were employed to analyze volatile components in samples from six production areas. A total of 73 and 56 volatile compounds were identified by HS-SPME-GC-MS and HS-GC-IMS, respectively. Quantitative analysis revealed that esters, aldehydes, and alcohols were the main contributors to the aroma profile, accounting for over 70% of the total relative content. Combined with chemometric analysis (VIP > 1 and OAV/ROAV > 1), 17 potential biomarkers were identified that can distinguish ‘Hujing Milu’ peaches from different regions, including ethyl acetate, hexanol, (E)-2-nonenal, and dihydro-β-ionone. Moreover, soil properties of these regions and their correlation with volatile compounds were analyzed to elucidate the formation mechanisms of characteristic aromas. The results showed that ethyl acetate exhibited a significant positive correlation with soil pH (r = 0.530, p < 0.05), whereas dihydro-β-ionone showed a significant positive correlation with soil organic matter (r = 0.587, p < 0.05) and available potassium (r = 0.830, p < 0.05). This study identified characteristic volatile compounds of ‘Hujing Milu’ peaches from different regions, providing a reliable technical basis for origin traceability and the enhancement of aroma quality in ‘Hujing Milu’ peaches. Full article

Royal jelly, a nutrient-rich bee product characterized by high water content and active components, is particularly susceptible to quality deterioration during storage. While temperature effects have been extensively documented, the specific role of light exposure in quality degradation remains largely unexplored. despite its relevance during production, handling, transportation, and display. This study systematically investigated the volatile organic compounds (VOCs) of royal jelly under different storage conditions using gas chromatography-ion mobility spectrometry (GC-IMS) combined with fingerprint analysis. Results from dual-column validation demonstrated that even short-term light exposure at 25 °C induced pronounced alterations in VOC profiles, triggering the accumulation of off-flavor aldehydes (e.g., hexanal, nonanal) and ketones, along with 2-furfural generated via Maillard reaction. Concurrently, characteristic fresh-aroma esters and alcohols were significantly depleted. Multivariate statistical analysis confirmed light exposure as the predominant factor driving quality deterioration, with temperature variation under dark conditions producing comparatively minor effects within the same short timeframe. This work provides the first systematic evidence establishing insights into early volatile changes in royal jelly and identifies key VOC markers that offer valuable insights for optimizing storage strategies and developing rapid quality monitoring protocols. Full article

Table grapes are widely consumed fruits, and their quality is largely determined by aroma, texture, and the accumulation of health-promoting compounds such as flavonoids. In this study, we systematically compared the edible quality and molecular basis of flavonoid biosynthesis among three major table grape cultivars: Crimson Seedless (CRS), Red Globe (RG), and Shine Muscat (SM). An integrated approach combining physicochemical assays, Gas chromatography–ion mobility spectrometry (GC-IMS)-based volatile profiling, and transcriptome sequencing (RNA-seq) was employed. Among the three cultivars, SM exhibited superior fruit quality, characterized by the highest firmness, total soluble solids, ascorbic acid, total phenolic content, and flavonoid content, whereas CRS showed the highest titratable acidity. Volatile compound analysis revealed distinct aroma profiles among the cultivars. SM was enriched in ethanol and 2-methylbutanal, contributing sweet and fruity notes, while CRS contained higher levels of C6 aldehydes, such as hexanal and (E)-2-hexenal, which are associated with green and leafy aromas. RG exhibited a relatively simpler volatile profile with lower overall abundance. Transcriptome analysis identified 20 differentially expressed genes involved in the flavonoid biosynthetic pathway, including PAL, C4H, 4CL, CHI, F3H, F3′H, and DFR, of which ten were significantly upregulated in SM. Eight of these genes showed strong positive correlations (r > 0.8) with flavonoid content. These results provide a comprehensive understanding of the metabolic and genetic mechanisms underlying cultivar-specific quality traits and identify promising candidate genes for breeding table grapes with enhanced flavor and health-promoting properties. Full article

To assess the impact of developmental stages on the postharvest quality of loquat, fruits at five distinct maturity phases (T1–T5) were systematically analyzed. This study employed a range of analytical techniques to conduct a comprehensive examination of the variations in quality, nutritional content, and volatile compounds of loquat across different developmental stages. Sensory evaluation indicated that the T4 stage achieved the highest score (93.21 ± 1.13), with significant differences observed in a* (6.56–13.08) and b* values (16.91–22.16). Both moisture content (45.45–86.94 g/100 g) and fruit firmness (8.65–3.31 N) exhibited a decline with delayed harvest (p < 0.05). Scanning electron microscopy (SEM) analysis revealed that, as the developmental period progressed, the pores in the loquat cell walls enlarged, and the cellular structure became increasingly relaxed. GC–MS and GC–IMS detected 48 and 47 volatile compounds, respectively. Using orthogonal partial least squares discriminant analysis (OPLS–DA), we identified 14 key compounds that distinguish the five developmental stages. E-nose and E-tongue analyses showed significant changes in the smell and taste profiles of loquats over time, with the T1 stage notably different from later stages. This study offers important insights and guidance on the postharvest quality of loquats at various developmental stages. Full article

A functional Huangjiu-based liqueur (called by Lujiu in China), a type of Chinese rice wine, was developed by incorporating Chinese gall leaven, as a medicinal–edible homologous ingredient, into the fermentation process to enhance its bioactivity. The physicochemical properties and enzymatic activities were investigated and found that supplementation with 2% (v/v) Chinese gall leaven optimized fermentation efficiency and substrate utilization. The co-fermentation significantly elevated the concentrations of bioactive compounds and improved antioxidant capacity, particularly free radical scavenging activity. Compared to traditional Chinese rice wine, the supplemented variant exhibited markedly higher levels of malic acid and phenolic acids. GC-MS analysis identified 85 and 84 volatile flavor compounds in the two supplemented variants, respectively, exceeding the 70 compounds detected in traditional Huangjiu. GC-IMS further revealed significant enrichment of key alcohols (e.g., 3-methyl-1-butanol, 2-methyl-1-propanol) and aldehydes (e.g., propanal, acetaldehyde) in the supplemented group. Microbial community analysis indicated distinct shifts, with increased relative abundances of Pediococcus, Lactiplantibacillus, Aspergillus, and Saccharomyces in the Chinese gall leaven-supplemented fermentation. These results suggest that the native microflora and enzymatic systems of Chinese gall leaven could enhance microbial metabolism and fermentation efficiency, thus contributing to the unique characteristics of rice wine and providing a novel strategy for functional Huangjiu-based liqueur production. Full article

In recent years, there has been substantial global progress in screening yeasts for fermenting various specialty fruits, especially non-Saccharomyces species known for their contributions to aroma enhancement. This study focused on mature fruits and soil samples collected from orchards located in the main production region of C. reticulata cv. ‘Dahongpao’ (CRCD) in China, with the objective of isolating specialized non-Saccharomyces yeasts suitable for producing CRCD fruit wine. After enrichment cultivation, seven characteristic yeast strains were isolated and purified. These isolates were identified as Candida parapsilosis, Meyerozyma caribbica, Candida quercitrusa, and Meyerozyma guilliermondii through a combination of microscopic morphology and molecular biology methods, which also included Pichia fermentans, Pichia kudriavzevii, and Pichia kluyveri. The strains’ fermentation potential, ethanol production rates, and tolerance levels were assessed, leading to the selection of Candida parapsilosis, Candida quercitrusa, Pichia fermentans, Pichia kudriavzevii, and Pichia kluyveri for further fermentation experiments. The commercial yeast La-Ma was used as a control. Analysis of volatile organic compounds (VOCs) in the fruit wine samples was performed using Gas Chromatography–Ion Mobility Spectrometry (GC-IMS). A total of 42 different VOCs were identified, with esters being the most prevalent. The fingerprint profiles demonstrated notable differences between the fruit wine samples fermented with selected yeasts and those fermented with commercial yeasts. Principal component analysis (PCA) indicated that Pichia kluyveri displayed the most significant divergence from both commercial and other selected yeasts. The samples contained notable VOCs such as 2-methyl-1-butanol, pentanal, 3-methyl-2-butenal, propyl acetate, butyl acetate, isobutyl acetate, isopentyl acetate, and 3-methyl-2-butenyl acetate, while the methanol production was observed to be lower compared to other samples. Consequently, this strain has the potential to produce distinctive fruit wine. Full article

Although aquatic products are abundant in premium proteins and other vital nutrients, their unique fishy smell often restricts public acceptance and the development of related products. Therefore, pre-marinating is usually used to improve sensory quality and mitigate fishy smell. In this study, sea bass filets were marinated for 1 h at a solid–liquid ratio of 3:5 (w/w) using 15% orange juice, 15% grapefruit juice, and 10% lemon juice. Subsequently, their effects on the flavor and sensory quality of sea bass were examined. The results of gas chromatography-ion mobility spectrometry (GC-IMS) showed that marinating the filets in citrus juice led to a notable increase in volatile compounds, including esters with fruity flavor such as ethyl butyrate and terpenes with pleasant citrus aromas such as limonene. The results of texture profile analysis (TPA) showed that pre-marinading with orange juice and grapefruit juice significantly reduced the hardness of fish and resulted in higher sensory evaluation scores (p < 0.05). Lemon juice treatment produced the most noticeable whitening effect (p < 0.05). These findings suggest that citrus juices can be effectively incorporated as marinade ingredients for sea bass, providing both theoretical insight and practical guidance for improving the marinating technology for aquatic products. 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

Lonicerae japonicae flos (LJF) is a natural product with medicinal, edible, and ornamental value which has been developed into LJF tea. At present, LJF tea can be processed using four main fixation methods: fixation by sun drying (SG), hot-air oven drying (HG), stir-frying drying (CZ), and steaming (ZZ). However, a comparative analysis of the effects of different fixation methods on the quality of LJF tea has not been reported. This study comprehensively investigated the effects of these fixation methods on the appearance color, volatile components, and non-volatile components of LJF tea samples. Our findings demonstrated that LJF tea in the SG group had the highest L value, causing a brighter appearance, which was mainly caused by the retention of organic acids and flavonoids. Additionally, LJF tea in the SG group had a higher content of aroma components than other groups. These results suggested that sun drying may be beneficial for improving the quality of LJF tea. This study provided a reference for the selection of fixation methods for LJF tea and offered a clue for quality improvement of LJF tea. Full article

The main characteristics of the large number of coffee species are differences in aroma and caffeine content. Labeled blends of Coffea arabica (C. arabica) and Coffea canephora (C. canephora) are common to broaden the flavor profile or enhance the stimulating effect of the beverage. New emerging species such as Coffea liberica (C. liberica) further increase the variability in blends. However, significant price differences between coffee species increase the risk of unlabeled blends and thus influence food quality and safety for consumers. In this study, a prototypic hyphenation of trapped headspace-gas chromatography-ion mobility spectrometry-quadrupole mass spectrometry (THS-GC-IMS-QMS) was used for the detection of characteristic compounds of C. arabica, C. canephora, and C. liberica in green and roasted coffee samples. For the discrimination of coffee species with IMS data, multivariate resolution with multivariate curve resolution–alternating least squares (MCR-ALS) prior to partial least squares–discriminant analysis (PLS-DA) was evaluated. With this approach, the classification accuracy, as well as sensitivity and specificity, of the PLS-DA model was significantly improved from an overall accuracy of 87% without prior feature selection to 92%. As MCR-ALS preserves the physical and chemical properties of the original data, characteristic features were determined for subsequent substance identification. The simultaneously generated QMS data allowed for partial annotation of the characteristic volatile organic compounds (VOC) of roasted coffee. Full article

Apple aroma is an important factor influencing consumers’ preferences. To understand the overall flavor characteristics of apples (Ruixue, Liangzhi, Grystal Fuji, and Guifei), volatile compounds and aroma profiles were investigated by headspace–gas chromatography–ion mobility spectrometry (HS-GC-IMS) combined with stir bar sorptive extraction (SBSE) and gas chromatography–mass spectrometry (GC-MS). The results showed that a total of 56 aroma compounds were identified by SBSE-GC-MS, and 39 aroma-active compounds were screened out using aroma intensity (AI) and odor activity value (OAV). Aroma recombination experiments showed enhanced ‘fruity’ and ‘sweet’ notes, whereas ‘floral’, ‘woody’, and ‘green’ aromas were weaker compared to the Crystal Fuji sample. Additionally, GC-IMS coupled with principal component analysis (PCA) was used to distinguish the apple samples, and partial least squares regression (PLSR) was applied to explore the correlation between sensory attributes and characteristic aroma compounds. The results indicated that Crystal Fuji exhibited the greatest correlation with the “woody” attribute, and Ruixue was highly correlated with “fruity”, “green”, and “sour” attributes, while butanoic acid, β-damascenone, butyl acetate, pentyl acetate, furfuryl alcohol, γ-decalactone, and vanillin had a significant impact on the “flower” and “sweet” attributes of Guifei. This study clarified the characteristic aroma composition of the four apple cultivars, providing data support for apple flavor quality evaluation and cultivar optimization. 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

Mycoplasma ovipneumoniae poses a major threat to sheep respiratory health, contributing to significant economic losses in farming communities. In this study, we isolated a novel strain, IM-DMQ, from a Hu sheep in Inner Mongolia that exhibited pulmonary adenomatous-like lesions, which is an uncommon pathological manifestation for this pathogen. The complete genome was sequenced using a hybrid Nanopore and Illumina approach, revealing a 1,039,804 bp circular chromosome with a GC content of 29.15%, encoding 1529 genes. Functional annotation highlighted genes involved in essential metabolic processes and potential virulence mechanisms. Comparative genomic analysis demonstrated that IM-DMQ shares the closest ancestry (ANI: 98.3%) with the Chinese strain NXNK2203, while structural variations and 14 unique genes distinguished it from other global strains. Furthermore, microbial community profiling of the original lung tissue revealed a co-infection background involving multiple bacterial pathogens, offering an etiological context for the severe disease presentation. These results provide the first complete genomic resource for an M. ovipneumoniae strain from Inner Mongolia associated with unusual pulmonary pathology, offering insights into its genetic diversity and supporting the future development of targeted diagnostics and vaccines for regional disease control. Full article

This study investigated the effect of superheated steam (SS) assisted glycosylation modification on the flavor profile of oyster peptides (OP), and explored the correlation between key flavor compounds and glycosylation degree using Gas Chromatography–Ion Mobility Spectrometry (GC-IMS) and nano-scale Liquid Chromatography coupled with High-Resolution Mass Spectrometry (nano-LC/HRMS). The results indicated that SS treatment accelerated the glycosylation process, reduced free amino groups level, and distinguished their unique flavor through E-nose. GC-IMS analysis detected 64 signal peaks including 13 aldehydes, 6 ketones, 7 esters, 6 alcohols, 2 acids, 2 furans and 5 other substances. And it was revealed that SS-mediated glycosylation treatment reduced the levels of fishy odorants like Heptanal and Nonanal, while promoting the pleasant-smelling alcohols and esters. In addition, Pearson correlation showed a positive correlation between excessive glycation and the increase in aldehydes, which might cause the recurrence of undesirable fishy notes. Further nano-LC/HRMS analysis revealed that arginine and lysine acted as the main sites for glycosylation modification. Notably, glycosylated peptides such as KAFGHENEALVRK, DSRAATSPGELGVTIEGPKE, generated by mild SS treatment could convert into ketones and pyrazines in subsequent reactions, thereby contributing to overall sensory enhancement. In conclusion, SS treatment at 110 °C for 1 min significantly improved the flavor quality of OP and sustains improvement in subsequent stages, providing theoretical support for flavor optimization of oyster peptides. Full article