Search Results (923)

Sauce-aroma Baijiu is produced through a one-year cyclic process involving multiple fermentations and distillations. However, the dynamic changes and correlations among fermented grains (FG), distilled fermented grains (DG), heart liquor (HL) and tail liquor (TL) remain unclear. In this study, the physicochemical indicators and volatile compounds (VCs) from the 3rd to 6th distillation rounds were systematically analyzed. Across successive rounds, FG and DG exhibited similar trends in key physicochemical indicators, as did HL and TL. Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS) identified 76, 73, 80 and 93 VCs in FG, DG, HL and TL, respectively. Multivariate statistical analyses revealed significant inter-round differences in volatile profiles, and further indicated that total acids and water contents in FG were positively correlated with the majority of VCs in liquor. These results clarify the dynamic change of physicochemical and flavor components during Baijiu production and provide a basis for quality evaluation. Full article

Blueberry fruit quality is characterized by multi-dimensional traits such as color, sugar-acid flavor, and volatile aroma. However, variations in progeny metabolites during seedling selection need further study. This research used the blueberry variety ‘Baldwin’ (BW) and its seedling offspring (BWSO) to compare fruit appearance, as well as sugar and acid components, anthocyanin monomers, and volatile metabolites. High-performance liquid chromatography was used to analyze anthocyanins, sugars, and acids, and gas chromatography–mass spectrometry was used to analyze volatile compounds. The results showed that, compared with BW, BWSO had a blacker skin and a lower L* value. Its total anthocyanin content increased by 35.90%, with delphinidin increasing the most (52.70%); component ratios were reconstructed. The main organic acids in BWSO decreased; titratable acid dropped by 29.82%, and the total soluble solids–acid ratio rose by 37.49%, indicating a good low-acid, high-sugar flavor. Forty-three differential volatile metabolites were found, and BWSO differed from BW in its green, fruity, and floral flavors. Notably, BWSO’s vitamin C (Vc) content decreased by 70.45% compared to BW, and Vc was negatively correlated with anthocyanin components. In conclusion, BWSO exhibits a black phenotype due to elevated total anthocyanins and restructured component ratios. Its low-acid trait yields better taste, but the antagonism between anthocyanin and Vc means balanced nutritional quality selection is crucial in dark-blueberry breeding. These findings offer new insights into the mechanism of color variation and provide a reference for balanced quality trait selection in seedling selection. Full article

Crackers and cookies have become the most widely consumed snacks due to their low production costs, long shelf life, and ability to deliver essential nutrients. Increasing consumer health consciousness has shifted preferences toward foods perceived as natural and beneficial. This shift elevates demand for cracker formulations with novel, health-promoting natural ingredients. This study examined the effects of incorporating freeze-dried olive leaf powder (FDOLP) into crackers on their physicochemical properties, phenolic and volatile compound profiles, antioxidant capacity, and sensory acceptability. Total polyphenol content of crackers was determined using the Folin–Ciocalteu method, while antioxidant capacity was evaluated by FRAP and DPPH assays. The UHPLC-ESI-HRMS analysis evaluated olive-derived compounds, including tyrosol, oleuropein derivatives, and pinoresinol 4-O-glucoside, present in olive leaf-enriched crackers. The characterisation of volatile compounds in crackers was performed using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS). A darker colour was observed in the enriched crackers compared to the control samples. Results demonstrated that increasing the proportion of FDOLP led to enhanced phenolic composition and antioxidant activity, as well as changes in the volatile profile of the crackers. Sensory analyses indicated that crackers enriched with moderate levels of FDOLP maintained acceptable overall sensory scores, suggesting a potential for the development of functional snacks. These findings demonstrate that olive leaves can be effectively utilised as a natural functional ingredient in cracker formulations to enhance their nutritional value and bioactive properties. Full article

Seasonal variation in aroma quality is critical for commercial grading of Xinyang Maojian (XYMJ) green tea, and how seasonal changes shape its volatile composition and aroma profile remains unclear. This study investigated the volatile profiles of XYMJ harvested in spring, summer, and autumn using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) analysis. A total of 93 volatile compounds were identified, with alkenes, alcohols, and esters being the most numerous chemical classes. Total volatile content decreased significantly seasonally (p < 0.05), being highest in spring (1716.68 μg/kg), followed by summer (1566.72 μg/kg) and autumn (1378.21 μg/kg). PCA and PLS-DA clearly distinguished seasons. Using a dual-filtering strategy (variable importance in the projection > 1.0 and p < 0.01), 14 differential volatile metabolites were identified as core seasonal markers. Geraniol, cis-jasmone, and indole were identified as key drivers of the premium floral fragrance in spring XYMJ, while cis-3-hexenyl hexanoate and linalool peaked in the summer harvest. OAV results and cross-modal sensory interaction principles suggest that the superior flavor of spring XYMJ arises from both higher aromatic intensity and an optimized aroma-taste balance. These findings provide useful insights into the seasonal variations in the metabolic and chemical profiles of XYMJ, enhancing our understanding of the biochemical markers associated with its production timeline. Full article

While withering is a critical processing step influencing the flavor profile of white teas, the effects of temperature-changing withering remain elusive. This study systematically investigated the variations in two withering methods (natural withering, temperature-changing withering) in volatile compounds of white teas made from four cultivars. The quality of white teas produced from ‘Mingshan No. 131’ (MS131), ‘Fuxuan No. 9’ (FX9), ‘Ziyan’ (ZY), and ‘Fudingdabai’ (FDDB) was evaluated using quantitative descriptive analysis (QDA), headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), and odor activity value (OAV) analysis. The sensory evaluation results indicated that temperature-changing withering enhanced the development of sweet and fruity aromas while suppressing grassy notes. A total of 176 volatile compounds were identified, and temperature-changing withering induced significant alterations in the aroma profile, notably increasing the levels of ketones, esters, and alkenes (p < 0.05). Based on the criteria of OAV > 1, p < 0.05, and a fold change ≥ 1.5 (for upregulated compounds) or ≤0.67 (for down-regulated compounds), key volatile compounds in white teas from the four cultivars were identified. The common upregulated volatile compounds, namely 1-octen-3-one, cedrol, (E,E)-2,4-heptadienal, and (E)-2-hexenal, promoted the fresh flavor profile of white teas. These findings demonstrate that temperature-changing withering optimizes flavor-related metabolites, thereby providing a theoretical foundation for improving white tea processing. Full article

Musalais is a traditional fermented beverage of the Uyghur people in Xinjiang, China. Its production involves boiling grape juice at high temperatures to concentrate it and enhance its sugar content, followed by natural fermentation. However, this high-temperature concentration process leads to a significant loss of bioactive and flavor compounds, adversely affecting the quality of the final product. Adding composite ingredients may help mitigate this quality decline. This study compares Musalais new product with traditional Musalais. Phenolic analysis showed that total monomeric phenols were 182.36 mg·L⁻¹ in the new product versus 14.76 mg·L⁻¹ in traditional Musalais. Headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC-MS) identified 72 volatile compounds in the new product (total content of 569,848.88 μg·L⁻¹) compared to 58 compounds (total content of 362,774.17 μg·L⁻¹) in traditional Musalais. Compared to traditional Musalais, the new product exhibits a 24.14% increase in volatile compound variety and a 57.09% increase in total concentration, with more pronounced floral, fruity, and vinous aromas, as well as higher sensory scores. Non-targeted metabolomics suggests that the new product may have superior phenolic and volatile profiles. Full article

Diallyl trisulfide (DATS), a volatile natural sulfur-containing compound derived from garlic, possesses antifungal and preservative potential. However, its biocontrol efficacy against postharvest gray mold of tomato and the molecular mechanisms underlying fruit quality maintenance remain unclear. In this study, we systematically investigated the inhibitory effect of DATS fumigation on postharvest gray mold, its role in fruit quality maintenance, and the associated molecular mechanisms through in vitro antifungal assays, physiological and biochemical measurements, transcriptome sequencing, and correlation analysis. In vitro experiments showed that DATS at 50 μL L⁻¹ completely inhibited spore germination and germ tube elongation of Botrytis cinerea in a concentration-dependent manner, and disrupted spore membrane integrity (FDA-positive spores dropped from 73.4% to 2.9% at 50 μL L⁻¹). In vivo experiments demonstrated that Bc + DATS treatment completely inhibited lesion development compared to the control Bc, enhanced the activities of superoxide dismutase, catalase and peroxidase (e.g., CAT activity 2.20-fold higher than Bc on day 3), decreased malondialdehyde accumulation (0.65-fold of Bc on day 4), and delayed the declines in total soluble solids, titratable acidity, soluble sugars and vitamin C content (VC content 4.14-fold higher than Bc on day 4). Transcriptomic analysis revealed that DATS treatment up-regulated genes involved in plant hormone signal transduction, ubiquitin-mediated proteolysis, and phenylalanine metabolism, while down-regulating core MAPK kinases and histidine decarboxylase. Correlation analysis demonstrated significant associations between the expression of these pathway genes and antioxidant enzyme activities, vitamin C content, and lesion diameter. Collectively, DATS achieves effective control of postharvest gray mold and maintenance of fruit quality in tomato through direct antifungal activity, synergistic activation of hormone/MAPK signaling, reprogramming of phenylalanine metabolism, and modulation of membrane lipid homeostasis. This study provides a theoretical and practical basis for developing DATS as a green postharvest preservative to reduce food loss and ensure food safety. Full article

This study presents a novel analytical approach combining headspace solid-phase microextraction (HS-SPME) with gas chromatography–mass spectrometry (GC–MS) and advanced chemometric techniques to detect adulteration in coriander honey. A total of 34 volatile compounds were identified and quantified, revealing a progressive decrease in both profile complexity and compound abundance with increasing levels of invert sugar and high-fructose corn syrup (HFCS) adulteration. Chromatographic and chemometric analyses effectively distinguished authentic from adulterated samples, with the Extreme Gradient Boosting (XGBoost) model achieving a high classification performance of 95.83% accuracy. The study highlights the critical impact of adulteration on honey’s chemical composition and confirms the efficacy of integrating modern analytical and machine learning tools for rapid, sensitive, and reliable honey authenticity assessment. This methodology offers a valuable framework for food quality control and fraud prevention, addressing current challenges in the honey market and protecting consumer interests. Full article

The chemical composition and sensory profile of coffee are influenced by brewing method, namely extraction pressure, temperature, contact time, and equipment. This study compared coffee prepared with a traditional moka pot, a conventional espresso machine, and a novel Italian device (Kamira). Volatile compounds were analyzed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC–MS), leading to the determination of furan (34–42%), pyrrole (4–10%), and pyrazine (13–14%) derivatives. The most abundant fatty acids were palmitic (36–37%), linoleic (40%), and oleic (11%) acids. Physicochemical parameters (total solids, pH, and refractive index) were also measured. Caffeine and chlorogenic acids were quantified by liquid chromatography (HPLC). Differences in chlorogenic acids and volatile compounds were associated with variations in bitterness, acidity, astringency, and aroma intensity. Finally, a trained panel performed sensory evaluation to evaluate the olfactory and flavor attributes of the three types of coffee brews. Significant differences emerged among brewing systems. Espresso showed the highest caffeine content (55.3 ± 4.1 mg/100 g) and total solids (2.61 ± 0.11 g/100 g), together with a stable crema and intense sensory attributes. Moka coffee exhibited a rich aromatic profile but limited crema. The Kamira device produced an abundant crema and a chemical profile partially comparable to espresso. These findings confirm that brewing technology markedly affects coffee composition and sensory perception. Full article

In 2024, China generated approximately 130 million tons of food waste. This study focuses on food wastewater characterized by exceptionally high organic strength (chemical oxygen demand (COD) > 80 g·L⁻¹, total suspended solids (TSS) > 20 g·L⁻¹) content. Conventional continuous stirred tank reactors (CSTRs) inherently couple hydraulic retention time (HRT) and sludge retention time (SRT), making them prone to microbial washout under high organic loading. To overcome this limitation, this study employed two anaerobic sequencing batch reactors (ASBRs) for treating such high-strength food wastewater. This study systematically evaluated the impacts of temperature (mesophilic: 37 °C and thermophilic: 55 °C) and organic loading rate (OLR) on fermentation performance. Under stable operation (OLR = 5.6 kg_COD·m⁻³·d⁻¹; HRT = 16 days), the mesophilic ASBR achieved a specific methane yield of 307 mL CH₄·g_CODremoved⁻¹, an average COD removal efficiency of 81%, and a volatile fatty acids-to-total alkalinity (VFA/TA) ratio of 0.2, indicating robust process stability. In contrast, the thermophilic ASBR exhibited a VFA/TA ratio of 0.5, signaling incipient acidification. Microbial community analysis revealed significantly higher bacterial and archaeal alpha diversity in the mesophilic system. Notably, Methanothrix—a versatile acetoclastic methanogen—dominated the mesophilic archaeal community (66.65%), conferring functional redundancy and resilience against organic shock loads. By contrast, the thermophilic system was overwhelmingly dominated by the hydrogenotrophic Methanothermobacter (99.28%), resulting in low functional diversity and structural fragility. Compared with a benchmark mesophilic CSTR (specific methane yield: 276 mL CH₄·g_CODremoved⁻¹; COD removal efficiency: 70.6%), the mesophilic ASBR improved methane yield by 11%, COD removal efficiency by 15%, and operational stability (VFA/TA = 0.2 vs. 0.6). This work addresses a gap in ASBR applications for high-strength food wastewater treatment and provides experimental validation of the performance, stability, and scalability of mesophilic ASBRs. The proposed process represents a technically feasible, resource-efficient, and operationally robust solution for the valorization of organic wastewater with COD > 80 g·L⁻¹ and TSS > 20 g·L⁻¹. Full article

The fermentation cycle critically influences flavor formation in Laobaigan Baijiu, but its effect on the bacterial community–flavor compound correlation remains unclear. This study investigated the co-variation between bacterial community turnover and flavor changes across distinct fermentation rounds of Hengshui Laobaigan Baijiu. Bacterial community structure was characterized via high-throughput sequencing (HTS), while volatile flavor compounds were profiled using headspace solid-phase microextraction combined with gas chromatography–mass spectrometry (HS-SPME–GC–MS). Partial least squares regression (PLSR) revealed their correlation. The analysis revealed 45 volatile compounds in total, with the D-2–D-3 stages serving as the peak production period and stages E-5–E-6 as the key formation period for esters. Lactobacillus dominated the early Dacha (first batch) fermentation, whereas Pseudomonas, Chryseobacterium, and Delftia became dominant after Jiuqu addition in Ercha (second batch). Sphingomonas and Pseudomonas were the major flavor contributors, showing very strong correlations with 9 and 6 compounds, respectively. Sphingomonas was positively correlated with nine compounds (e.g., isoamyl acetate, ethyl pentanoate, acids, benzaldehyde), while Pseudomonas was positively correlated with six esters (e.g., ethyl acetate, ethyl butyrate). Delftia, Pantoea, and Lactobacillus also played important roles in volatile formation. This study establishes a correlation network between bacterial communities and flavor compounds in a multi-round solid-state fermentation system, offering a methodological reference for flavor regulation not only in Laobaigan Baijiu but potentially in other traditional fermented foods with similar batch fermentation processes. This study provides theoretical support for the optimization of Laobaigan Baijiu fermentation and the enhancement of final Baijiu quality. Full article

The transition toward renewable energy sources has become a critical global objective. For developing nations facing the dual challenges of inefficient waste management and limited energy access, waste-to-energy (WTE) technologies offer a transformative solution to mitigate environmental concerns while enhancing power grid stability. This paper presents a detailed performance analysis of a proposed WTE thermal power plant for Dire Dawa City, Ethiopia, utilizing municipal solid waste (MSW) as a sustainable feedstock. The primary objective of this study is to estimate the power generation potential of the city’s MSW through thermal incineration integrated with a Rankine Vapor Cycle. Field data collection reveals that Dire Dawa City produces an average of 237.2 tons of waste daily, with a per capita generation rate of 0.49 kg. Laboratory characterization indicates that the waste possesses high energy potential, featuring an average calorific value of 18.20 MJ/kg (18.20 × 10³ kJ/kg), a volatile matter content of 73.50%, and fixed carbon at 19.18%. Thermodynamic modeling and energy-flow simulations demonstrate that the facility can achieve a power output ranging from 7.64 MW to 22.80 MW, providing a nearly constant total energy yield of approximately 183,360 kWh per day. These results confirm that Dire Dawa City’s waste stream is a potent strategic resource for renewable energy. Ultimately, this research provides a technical roadmap for stakeholders, facilitating informed investment decisions and resource planning to ensure the successful implementation of sustainable thermal energy infrastructure in the region. Full article

This study investigates the volatile composition of twelve medicinal plant species belonging to the Lamiaceae family, which are widely recognized for their diverse biological activities, including antioxidant, antibacterial, and antifungal properties. Despite extensive studies on essential oils, comparative analyses using solvent-free techniques under different microclimatic conditions remain limited. This study investigates the volatile compounds in twelve medicinal plants from the Lamiaceae family using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS). Lamiaceae plants are recognized for their diverse medicinal properties, including antioxidative, antibacterial, and antifungal effects. A total of 74 volatile compounds were identified, encompassing terpenes, alcohols, esters, aldehydes, and ketones. Notably, Lavandula spica L. exhibited the highest number of unique volatiles (28), while Melissa officinalis L. had the fewest (16). Key compounds included Citral (65.48%) in Melissa officinalis L., Menthol (33.37%) and Menthyl acetate (30.53%) in Mentha piperita L., Carvone (45.86%) in Mentha spicata L., and Eucalyptol (54.71%) in Origanum syriacum L. Plants from Adana Botanic Park were rich in terpenes and ketones, whereas those from Osmaniye contained higher levels of alcohols, aldehydes, and esters. The findings emphasize the impact of geographic location on volatile profiles and suggest avenues for further research into medicinal efficacy and optimal dosage. This study supports the sustainable use of plant biodiversity (SDG 15) and highlights the importance of bioactive compounds for human health and well-being (SDG 3). Full article

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

This study evaluates the impact of the complete early leaf removal on the fruit zone for consecutive growing seasons (2023–2024) on the agronomic performance and oenological potential of the indigenous Greek red cultivar Avgoustiatis (Vitis vinifera L.), which is cultivated in Zakynthos, Greece. The defoliated treatment significantly reconfigured vine productivity, inducing a 33–34% reduction in yield during both years of the study and a contraction in berry mass, which consequently increased the skin-to-berry ratio by 30% and 60% for the 2023 and 2024 vintages, respectively. In the must, defoliation facilitated a desirable decoupling of sugar and acidity, achieving higher soluble solids while maintaining a robust acid core. Furthermore, defoliation enhanced phenolic maturity, in both vintages, increasing total anthocyanins and improving their extractability. Although extreme thermal conditions in 2024 led to lower color intensity and total phenolics in the treated wines compared to the control, the volatile profile revealed a significant reduction in herbaceous C₆ alcohols and an increase in floral terpenes like nerol. Sensory analysis confirmed that defoliated wines were characterized by lower astringency and superior aromatic typicity, with distinct notes of violet and vanilla. These findings suggest that early defoliation is a potent tool for optimizing the structural and aromatic integrity of Avgoustiatis, though its application must be adapted against Mediterranean thermal stress. Full article