The flavor stability of tea beverages during storage has long been a concern. The study aimed to explore the flavor stability of Longjing green tea beverage using accelerated heat treatment trials, addressing the shortage of lengthy storage trials. Sensory evaluations revealed changes in bitterness, umami, overall harmonization, astringency, and ripeness as treatment duration increased. Accompanied by a decrease in L-values, ΔE and an increase in a and b-values. Seventeen non-volatile metabolites and three volatile metabolites were identified differential among samples by metabolomics, with subsequent correlation analysis indicating associations between sensory attributes and specific metabolites. Umami was linked to epigallocatechin 3,5-digallate and alpha-D-glucopyranose, astringency was correlated with ellagic acid and 1-ethyl-1H-pyrrole. Ripeness showed associations with ellagic acid, 6,7-dihydroxycoumarin, heptanal, and benzaldehyde, and overall harmonization was linked to 6,7-dihydroxycoumarin, β-myrcene, α-terpineol, and heptanal. A series of verification tests confirmed the feasibility of accelerated heat treatment trials to replace traditional storage trials. These results offer valuable insights into unraveling the complex relationship between sensory and chemical profiles of green tea beverages.

Mechanized production of Jiangxiangxing Baijiu (JB) stands as a pivotal trend in today\'s Baijiu industry. This study, employing high-throughput sequencing and headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) technology, comprehensively analyzed the micro ecology, physicochemical factors, and volatile components during pit fermentation, comparing traditional fermentation Zaopei (TZP) and mechanized fermentation Zaopei (MZP). According to the research findings, the dominant microorganisms in the fermentation process of ZP comprise Lactobacillus, Monascus, Issatchenkia, and Zygosaccharomyces. In addition, functional microorganisms like Zygosaccharomyces, Monascus, Issatchenkia, Leiothecium, Candida, Pichia, and others exhibited differences on day 0 and throughout the fermentation process. These differences are attributed to the effects of distinct fermentation environment and physicochemical factors. Furthermore, comprehensive analysis detected 87 volatile compounds in TZP and MZP, with 56 showing significant differences, primarily including alcohols, aldehydes, ketones, acids, esters, and aromatics. Additionally, fermentation can be classified into two phases based on ethanol and volatile compounds production: the initial phase (0-12 days, P1) primarily focuses on alcohols production, while the subsequent phase (12-30 days, P2) concentrates on volatile compounds generation. The subsequent correlation analysis indicates that variations in volatile compounds primarily arise from shifts in microbial composition, with notable differences observed in fungi, specifically Monascus, Zygosaccharomyces, and Issatchenkia, which drive the disparities in volatile compounds. This study provides an important theoretical basis and practical guidance for the realization of mechanized high-quality production of JB.

This research aims to assess the effect of amino acids as lipid antioxidants in reducing the formation of volatile aldehydes in frying oil. Methionine, histidine, and glycine at concentrations of 2.5, 5, and 10 mM were added to high oleic sunflower oil (HOSO) to investigate their effects on the distribution and formation of saturated, monounsaturated, and polyunsaturated volatile aldehydes. The results showed that the proportion of saturated volatile aldehydes was greater than that of unsaturated ones; Methionine exhibited the best inhibitory effect, after 12 h of frying, 10 mM methionine reduced the content of saturated volatile aldehydes by 24.21 %, monounsaturated by 52.4 %, and polyunsaturated by 54.73 % compared to the control. Methionine\'s sulfur-containing side chain was also proven to have strong antioxidant activity. Combined with the results of this study, this can also provide insights for using amino acids as lipid antioxidants.

Mannoproteins have traditionally been recognized as effective wine organoleptic modulators, however, ambiguous understanding of the relationship between their organoleptic functions and physiochemical characteristics often lead to inappropriate application in winemaking. To reveal the possible role the physiochemical characteristics of mannoproteins play in modulating wine color and aroma properties, three water-soluble mannoproteins (MP1, MP2, MP3) with different physiochemical characteristics have been prepared, and accelerated red wine aging, malvidin pigments formation experiments, accelerated aroma release experiments have been designed to observe their organoleptic modulating functions in this research. Results suggest that the phenolic/chromatic stability of red wines could be enhanced by MP3, probably due to its low steric hindrance potential, high reactivity, and good hydro-alcoholic stability conferred by its high Mannan/Glucan ratio (8.68), abundant hydrophobic/hydrophilic amino acids (65.29 % of total protein), and low/medium molecular weight level (30.71-57.77 kDa), respectively, which protected the phenolic compounds and promoted the formation of pyranoanthocyanins. Mannoproteins could modulate the volatility of aroma compounds by expelling or retention effects, which depended on the duration of mannoprotein application (the expelling effect was firstly observed possibly because of the significant adsorption of free H2O by MPs) and the types of mannoproteins. MP1 and MP2 were prone to retain and expel aroma compounds, respectively, probably due to their medium/high molecular weight levels (60.48-135.39 kDa) that conferred abundant interacting sites, and the high proportion of hydrophobic and hydrophilic components in MP1 (97.71 % polysaccharides of total mannoprotein, 34.58 % hydrophobic amino acids of total protein) and MP2 (97.96 % polysaccharides of total mannoprotein, 28.36 % hydrophobic amino acids of total protein) guaranteed a relatively higher interacting frequency with aroma compounds and free H2O molecules, respectively.

Withering is the first and key process that influences tea quality, with light quality being a key regulatory factor. However, effects of withering light quality (WLQ) on transformation and formation pathways of tea aroma and volatile metabolites (VMs) remain unclear. In the present study, four WLQs were set up to investigate their effects on tea aroma and VMs. The results showed that blue and red light reduced the grassy aroma and improved the floral and fruity aroma of tea. Based on GC-MS/MS, 83 VMs were detected. Through VIP, significant differences, and OAV analysis, 13 key differential VMs were screened to characterize the differential impacts of WLQ on tea aroma. Further analysis of the evolution and metabolic pathways revealed that glycoside metabolism was the key pathway regulating tea aroma through WLQ. Blue light withering significantly enhanced glycosides hydrolysis and amino acids deamination, which was beneficial for the enrichment of floral and fruity VMs, such as geraniol, citral, methyl salicylate, 2-methyl-butanal, and benzeneacetaldehyde, as well as the transformation of grassy VMs, such as octanal, naphthalene, and cis-3-hexenyl isovalerate, resulting in the formation of tea floral and fruity aroma. The results provide theoretical basis and technical support for the targeted processing of high-quality tea.

In this study, flavor characteristics and dynamic change of Chinese traditional fermented fish sauce (Yu-lu) with different fermentation time (2, 4, 6, 8, and 12 months) were analyzed. The electronic nose analyses confirmed a notable flavor change in fish sauce samples from different stages. During the 12-months fermentation, the total volatile compounds in fish sauce increased from 3.9 mg/L to 13.53 mg/L. Acids, aldehydes, esters and phenols were the main aroma substances and their contents gradually increased during the fermentation process. The PCA of GC-MS and GC-IMS showed that fish sauce samples from different fermentation periods can be well distinguished. A total of 110 volatile compounds identified by GC-MS, and 102 volatile compounds were detected by GC-IMS. Among them, 13 compounds were identified by both GC-MS and GC-IMS. The most varieties (49) of volatiles appeared after 8 months of fermentation. The odor activity value (OAV) analysis showed that 10 volatile compounds were considered as characteristic flavor in traditional fish sauce. The variable influence on projections (VIPs) in PLS-DA models constructed by GC-MS and GC-IMS identified 5 and 10 volatile compounds as biomarkers, respectively. Our results revealed the dynamic changes of characteristic flavor in fish sauce in combination of GC-MS and GC-IMS, which provides theoretical basis for the production and flavor regulation of fish sauce.

This study employed a combination of principal component analysis (PCA) and gas chromatography-ion mobility spectrometry (GC-IMS) to examine the distinctive taste mixtures produced by Chinese spicy cabbage (CSC) fermented at varying temperatures. As the fermentation progressed, the pH gradually decreased and stabilized after the 11 days of fermentation, and the total content of organic acids and short-chain fatty acids increased. A total of 49 volatile mixtures were detected during CSC fermentation and storage for 21 days. These included 7 aldehydes, 6 alcohols, 7 esters, 6 ketones, 5 pyrazines, 4 sulfides, 4 phenols, 2 ethers, 2 olefins, and 1 acid. With time, the content of most volatile flavor substances decreased. PCA of the signal intensities of the volatile chemicals in the samples showed significant differences in the flavor of CSC fermented at different temperatures; consequently, the samples fermented at different temperatures were effectively separated in relatively independent regions of CSC. Therefore, low-temperature fermentation and storage at 4 °C were more suitable for CSC. Based on the identified volatile chemicals, HS-GC-IMS and PCA could effectively construct the flavour fingerprints of CSC samples. This study provided a theoretical basis for improving the fermentation quality of CSC.

BACKGROUND: In this study, exhaled breath testing has been considered a promising method for the detection and monitoring of breast cancer (BC).
METHODS: A high-pressure photon ionization time-of-flight mass spectrometry (HPPI-TOFMS) platform was used to detect volatile organic compounds (VOCs) in breath samples. Then, machine learning (ML) models were constructed on VOCs for the diagnosis of BC and its progression monitoring. Ultimately, 1981 women with useable breath samples were included in the study, of whom 937 (47.3 %) had been diagnosed with BC. VOC panels were used for ML model construction for BC detection and progression monitoring.
RESULTS: On the blinded testing cohort, this VOC-based model successfully differentiated patients with and without BC with sensitivity, specificity, and area under receiver operator characteristic curve (AUC) values of 85.9 %, 90.4 %, and 0.946. The corresponding AUC values when differentiating between patients with and without lymph node metastasis (LNM) or between patients with tumor-node-metastasis (TNM) stage 0/I/II or III/IV disease were 0.840 and 0.708, respectively. While developed VOC-based models exhibited poor performance when attempting to differentiate between patients based on pathological patterns (Ductal carcinoma in situ (DCIS) vs Invasive BC (IBC)) or molecular subtypes (Luminal vs Human epidermal growth factor receptor 2 (HER2+) vs Triple-negative BC (TNBC)) of BC.
CONCLUSIONS: Collectively, the HPPI-TOFMS-based breathomics approaches may offer value for the detection and progression monitoring of BC. Additional research is necessary to explore the fundamental mechanisms of the identified VOCs.

Sorption-based atmospheric water harvesting (SAWH) is a promising solution for localized high-quality water production. Application of SAWH indoors offers dual benefits of on-site water generation and humidity control. This study evaluated the use of SAWH for water production in residential or office buildings, employing a portable zeolite-based SAWH device. Over the twelve-month testing period in the arid southwestern USA, the device achieved a median water yield of 3.6 L/day at a cost 30 % less than bottled water sold in the U.S. A mathematical model was developed for predicting water yield under different temperature and relative humidity (RH) conditions. Daily water yields were well fitted with the modified Langmuir model, with absolute humidity serving as the only prediction variable. Water extracted from a well-ventilated office building generally met the drinking water standards set by USEPA. However, elevated levels of dissolved organic carbon (DOC) were detected in the samples collected from the residential house (median = 32.6 mg/L), emphasizing the influence of human activities (e.g., cooking) on the emission of volatile and semi-volatile organic compounds in the air, which consequently reside in harvested water. Aldehydes and volatile fatty acids (formate, acetate) comprised roughly 50 % of the DOC found in the AWE water. A carbon fiber filter was not effective at removing these substances, highlighting the need for further research into effective treatment methods for DOC management before the safe use of AWE water. Overall, this study provides critical insights for the practical application of indoor SAWH as a decentralized source of high-quality water and emphasizes the need to identify and manage DOC for its safe use.

Methylation represents a crucial class of modification that orchestrates a spectrum of regulatory roles in plants, impacting ornamental characteristics, growth, development, and responses to abiotic stress. The establishment and maintenance of methylation involve the coordinated actions of multiple regulatory factors. Methyltransferases play a pivotal role by specifically recognizing and methylating targeted sites, which induces alterations in chromatin structure and gene expression, subsequently influencing the release of volatile aromatic substances and the accumulation of pigments in plant petals. In this paper, we review the regulatory mechanisms of methylation modification reactions and their effects on the changes in aromatic substances and pigments in plant petals. We also explore the potential of methylation modifications to unravel the regulatory mechanisms underlying aroma and color in plant petals. This aims to further elucidate the synthesis, metabolism, and regulatory mechanisms of various methylation modifications related to the aroma and color substances in plant petals, thereby providing a theoretical reference for improving the aroma and color of plant petals.