Headspace Solid-phase Microextraction Research Articles

Composition of Higher Alcohols in Different Alcoholic Beverages and Their Metabolic Dynamics in Bama Pigs.

The unique flavour contribution of higher alcohols in alcoholic beverages has received growing attention; however, there is a dearth of information on their in vivo metabolic kinetics. In this study, the composition and content of higher alcohols in different alcoholic beverages from Chinese Baijiu and Lujiu were studied via in vivo analysis using Bama pigs to elucidate the mechanisms for intoxication of alcohol in vitro and in drinkers. Direct injection combined with gas chromatography-mass spectrometry (GC-MS) were used to accurately quantify a total of 14 higher alcohols in five alcoholic beverages. Based on the external standard method, a total content of 289.37-938.33 mg/L was detected, mainly 1-butanol, 3-methyl-1-butanol, 1-hexanol, 2-methyl-1-propanol and 2-butanol. Then, headspace solid-phase microextraction (HS-SPME) and solid-phase extraction (SPE) combined with GC-MS analysis strategy, respectively, were adopted to continuously monitor the changes in the concentrations of ethanol and 11 higher alcohols in the blood within 24 h after gavage of different alcoholic beverages, and the key pharmacokinetic parameters were analysed. The peak concentration (Cmax) and area under curve (AUC) of blood higher alcohols were significantly lower than those of ethanol (p < 0.05), accompanied by a later peak time (Tmax) and a larger apparent clearance rate (CL_F), and there were certain differences between the same higher alcohols in different alcoholic beverages and between different higher alcohols in the same alcoholic beverage. This work provides valuable insights into the metabolism of alcoholic beverages.

The effect of indigenous non-Saccharomyces yeasts on the volatile profile of Maraština wine: Monoculture versus sequential fermentation

Non-Saccharomyces yeasts are presented as a new promising tool in winemaking to enhance aroma complexity in fermentation with Saccharomyces yeasts. Indigenous yeasts are recognized for their better adaptation to environmental conditions and for highlighting the unique terroir impact on wine aroma characteristics. To study the individual impact of ten indigenous non-Saccharomyces yeasts on the primary metabolites and volatile compounds of wine from autochthonous Croatian Maraština variety, Hyphopichia pseudoburtonii, Metschnikowia chrysoperlae, Metschnikowia sinensis/shanxiensis, Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora uvarum, Hanseniaspora guilliermondii, Hanseniaspora pseudoguilliermondii, Pichia kluyveri, and Starmerella apicola were inoculated in sterile grape juice in monoculture fermentations. Additionally, seven of them were also studied in sequential fermentation of sterile grape juice with commercial Saccharomyces cerevisiae. A targeted approach was used for the identification of volatile compounds via headspace solid-phase microextraction coupled with gas chromatography and a mass spectrometer. P. kluyveri and H. uvarum produced higher total concentrations of terpenes in sequential versus monoculture fermentation. Sequential fermentation of M. chrysoperlae, L. thermotolerans, and P. kluyveri with S. cerevisiae resulted in higher production of C13-norisoprenoids. The esters concentration was higher in monocultures for L. thermotolerans, H. uvarum, and H. guilliermondii, whereas other isolates showed higher concentrations in sequential fermentations. The results highlighted different indigenous yeast metabolisms and provided promising insights into potential new non-Saccharomyces starter cultures as a first step in their selection, with several species characterized in terms of their potential effect on the aroma profile.

Unrevealing the Halyomorpha halys Damage Fingerprint on Hazelnut Metabolome by Multiomic Platforms and AI-Aided Strategies.

The brown marmorated stink bug (Halyomorpha halys) poses a significant threat to hazelnut crops by affecting kernel development and causing quality defects, reducing the market value. While previous studies have identified bitter-tasting compounds in affected kernels, the impact of stink bug feeding on the hazelnut metabolome, particularly concerning aroma precursors, remains underexplored. This study aims to map the nonvolatile metabolome and volatilome of hazelnut samples obtained by caging H. halys on different cultivars in two locations to identify markers for diagnosing stink bug damage. Using a multiomic approach involving headspace solid-phase microextraction (HS-SPME), comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF MS), and liquid chromatography-high-resolution mass spectrometry (LC-HRMS), both raw and roasted hazelnuts are analyzed, with artificial intelligence (AI) and machine learning tools employed to explore data correlations. The study finds that the hazelnut metabolome and volatilome exhibit high chemical complexity with significant classes of compounds such as aldehydes, ketones, alcohols, and terpenes identified in both raw and roasted hazelnuts. Multivariate analysis indicates that the orchard location significantly impacts the metabolome, followed by damage type, with cultivar differences being less pronounced. Partial least-squares discriminant analysis (PLS-DA) models achieve high predictive accuracy for orchard location (99%) and damage type (≈80%), with the roasted volatilome showing the highest predictive accuracy. Correlation matrices reveal significant relationships between raw hazelnut metabolites and aroma compounds in roasted samples, suggesting potential markers for stink bug damage that could guide the quality assessment and mitigation strategies. Data fusion techniques further enhance classification performance, particularly in predicting damage type, underscoring the potential of integrating multiple data sets for comprehensive quality assessment.

Characterization of Changes in Ripening Process of Volatile Apple Compounds Based on HS-SPME-GC-MS Analysis

The aim of this study was to identify the aromatic compounds present in different apple varieties and to gain insights into the changes in the aromatic compounds during ripening. Three apple varieties (“Red Astrachan”, “Ning Qiu”, and “Golden Delicious”) at different stages of ripening were selected for this study; their peel and pulp were analyzed via headspace solid-phase microextraction (HS-SPME)–gas chromatography–mass spectrometry (HS-SPME-GC-MS), and 30 volatile compounds were identified. The samples’ differences were analyzed using heat map cluster analysis, principal component analysis (PCA), and an independent samples t-test. The results showed that the content of aromatic compounds in the peel was higher than that in the pulp. The relative content of esters in the aromatic compounds of the three apple varieties followed the order of pulp &gt; peel and “Ning Qiu” &gt; “Golden Delicious” &gt; “Red Astrachan”. This suggests that “Ning Qiu” combines the advantages of its parents in terms of its aroma content. The highest concentrations of aroma compounds in “Red Astrachan” and “Ning Qiu” accumulate before the ripening stage, and care should be taken to choose an appropriate harvesting time according to the different needs during production. The main compounds of “Red Astrachan” are aldehydes and C8 esters, while those of “Ning Qiu” and “Golden Delicious” are alkenes and esters. After analyzing the relative odor activity values (rOAVs) of key volatile compounds and their aroma descriptors during the harvest period, acetic acid pentyl ester, butanoic acid hexyl ester, hexanoic acid hexyl ester, and 2-ethyl-1-Hexanol were found to contribute the most to the overall flavor of the peel and pulp. “Ning Qiu” combines the parental advantages of the concentrated peel of “Red Astrachan” and the astringent pulp of “Golden Delicious”, with compounds in its composition that give a pleasing aroma. Mature “Ning Qiu” fruits have a more intense aroma and fruity flavor. The development of flavor-specific varieties has provided the theoretical basis for future research in molecular hybridization, molecular-assisted breeding, and the molecular biology of apple flavor synthesis and metabolism.

Translating 2D-Chromatographic Fingerprinting to Quantitative Volatilomics: Unrevealing Compositional Changes in Maize Silage Volatilome for Robust Marker Discovery.

This study examines the complex volatilome of maize silage, both with and without commercial heterolactic strain inoculation, conserved for 100 days, using quantitative volatilomics. Chemical classes linked to microbial metabolism were analyzed across a concentration range from 10 μg g-1 to 1 ng g-1. A reference method using comprehensive two-dimensional gas chromatography (GC × GC) and time-of-flight mass spectrometry (TOF MS) with loop-type thermal modulation (TM) was translated to a differential-flow modulation (FM) platform with parallel MS and flame ionization detector (FID) detection. With translation, the original method's analyte elution order and resolution are preserved. The new method allowed for accurate quantification using multiple headspace solid-phase microextraction (MHS-SPME) and FID-predicted relative response factors (RRFs). Both methods showed comparable discriminatory power with FM GC × GC-MS/FID achieving satisfactory quantification accuracy without external calibration. Analysis of 98 volatiles provided insights into silage fermentation, supporting marker discovery and correlations with silage quality and stability.

Identification of Volatile Organic Compounds and Analysis of Aroma Characteristics in Ten Pear Syrups.

Aroma in food plays an important role in food perception and acceptance, which depends on various mixtures of volatile organic compounds (VOCs). Moreover, VOCs are of great significance for aroma identification. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) technology was used to determine the VOCs in 10 pear syrups. A total of 127 VOCs were quantitatively determined, including 9 common VOCs and 46 characteristic VOCs of 10 pear syrups. The pear syrups were divided into three categories by cluster analysis, and thirty-eight differential VOCs were obtained using orthogonal partial least squares discrimination analysis (OPLS-DA) and fourteen key VOCs were selected by odor activity value (OAV). It was revealed that the key and common aroma components of pear syrups were butanoic acid, methyl ester, 2-methyl-, methyl ester and Hexanoic acid, and ethyl ester. The characteristic and differential VOCs were 10-Undecen-1-ol, Hexadecanal, n-Propylacetate, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1S,2R,5S)-, Methional, Disulfide, dimethyl, 8-Nonenoic acid, ethyl ester, Naphthalene, 1,2-dihydro-1,1,6-trimethyl-, 3H-Purin-6-amine, N,N,3-trimethyl-, 2-Octanol,2,6-dimethyl-, Furyl hydroxymethyl ketone, Heptane, 2,2,4,6,6-pentamethyl-, and Butanoic acid,2-methyl-,methyl ester. The above results showed that different pear syrups had rich diversity in aroma compounds, with some components being shared among them while others are exclusive to specific syrups.

Artificial intelligence tools and concepts give access to authenticity and quality information in Brazilian olive oil volatilome

Brazil is the world's second largest importer of olive oil and stared to produce its own oil quite recently in two distinct geographic areas. The production is still very small, and studies regarding oil composition are scarce. Determination of discriminant differences are useful to support appeals regarding origin indication and to detect fraud and adulteration with oils from other countries. In this work the Brazilian extra virgin olive oils (EVOOs) volatilome is explored by Artificial Intelligence (AI) tools developed on multiple headspace solid-phase microextraction (MHS-SPME) combined with comprehensive 2D gas chromatography-mass spectrometry and flame ionization detection (GC×GC-MS/FID) data. Using MHS-SPME, external standard calibration, and FID predicted relative response factors (RRF), the accurate quantification of 51 informative volatile compounds was carried out and the odorants responsible for key-positive sensory attributes were used to generate distinctive aroma blueprints aligned with the AI smelling based on sensomics. As authenticity and origin assessment decision-making tool, augmented visualization by computer vision was applied on volatilome 2D fingerprints. By this approach, extra-virgin olive oil samples (n=35), from two olive cultivars (Arbequina and Koroneiki) harvested in the main producing regions in Brazil (Rio Grande do Sul and Serra da Mantiqueira) in 2021 and 2022, were effectively discriminated and mislabeled products regarding their geographical origin were, for the first time, promptly identified.

Volatiles potentially useful to be used as biomarkers for monitoring the khapra beetle Trogoderma granarium for quarantine

The khapra beetle, Trogoderma granarium, is one of the most important quarantine pests globally. In order to identify potential biomarkers for establishing a rapid and effective monitoring technology for T. granarium quarantine, headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrum (GC-MS) was used to identify volatiles that are potentially useful for early detection of the presence of the T. granarium presence. Three volatiles, including Ethyl palmitate, (Z)-5-tetradecenoic acid and (Z)-14-methyl-8-hexadecen-1-al, were commonly identified as unique volatiles emitted from four different stored products including peanut, barley, wheat and rapeseed only after T. granarium infestation. In addition, four volatiles including hexadecane, palmitic acid, (Z)-14-methyl-8-hexadecen-1-al and N-heptadecane, were found emitted commonly from the larvae of T. granarium after they fed on the four stored products. These common chemicals could potentially be biomarkers sensitive enough for monitoring the presence of T. granarium. In addition to these unique chemicals, a combination of up- and down-regulated volatiles by each type of stored seeds were also identified as potential markers useful for the early detection of the presence of T. granarium. Our results could be a first step towards establishing a method for T. granarium monitoring and quarantine.

Behavioural responses of Sitophilus granarius (L.) and Rhyzoperta dominica (F.) to odours of old and modern wheat genotypes

Sitophilus granarius (L.) and Rhyzopertha dominica (F.) are among the major stored-product pests worldwide. The identification of low or un-attractive wheat genotypes toward storage pests and their Volatile Organic Compounds (VOCs) profile is useful in breeding programs and in characterization of behaviourally active compounds suitable in developing semiochemical-based control means. Old wheat cultivars are genetic resources useful for breeding purposes. In this study, the VOC profiles of old genotypes, Senatore Cappelli, old Saragolla, Dauno III, and modern wheat varieties, Mec, Ofanto, Svevo, and Faridur, were characterized by headspace - solid phase microextraction (HD-SPME) and gaschromatography coupled with mass spectrometry (GC-MS) and their attractiveness towards S. granarius and R. dominica adults was evaluated in two-choice pitfall bioassays and Y-tube olfactometer, respectively. Sitophilus granarius adults were significantly attracted to odours of all varieties, with females being significantly more attracted by Faridur, Ofanto, Mec, and old Saragolla compared to Svevo. Rhyzopertha dominica males and females exhibited a significant olfactory preference for the odours of Faridur, Mec, and old Saragolla. The olfactory preferences of both species could be related to differences emerged in varietal VOC profiles. The most attractive variety for both species, Faridur, was rich in alcohols, alkanes, and terpenes. Old Saragolla, Ofanto, and Mec were rich in alcohols and organic acids. Dauno III was the richest variety in alcohols and lactones, and the poorest in aldehydes and terpenes compared to other varieties. Svevo showed the lowest amounts of alcohols and the highest value of aldehydes; Senatore Cappelli was rich in aldehydes, organic acids, and alkanes. The possible effects of the differences in VOC profiles on the olfactory preferences of insects are discussed. The study offers new knowledge for further investigation testing VOCs of the most and the lowest attractive varieties to identify effective attractants or strong repellents towards S. granarius and R. dominica.

The effect of cold plasma treatment on the fruit quality and aroma components of winter jujubes (Ziziphus jujuba Mill. 'Dongzao').

Cold plasma (CP) is a novel environmental-friendly preservation technology that causes minimal damage to fruits. The flavor and quality of winter jujubes have decreased with the extended storage time. Currently, the research on the use of CP on winter jujubes (Ziziphus jujuba Mill. 'Dongzao') mainly focuses on the effect of the treatment on storage quality. There is limited research on the effect of CP treatment on the flavor of winter jujubes. This study used different CP (80kV) treatment durations (0, 5, and 10min) to treat winter jujubes. The appropriate treatment time was selected by observing the changes in color, respiratory intensity, soluble sugar content, total acid content, and vitamin C (VC) content of winter jujubes. Amino acid analyzer and headspace solid-phase microextraction in combination with gas chromatography coupled with mass spectrometric detection were used to analyze the effect of CP treatment on the flavor compounds of winter jujubes. The results showed that the 5-min CP treatment could significantly slow down the red coloration of winter jujube while maintaining high soluble sugar, total acid, and VC content. At the respiration peak, the respiratory intensity of the 5-min CP treatment group was 0.74 mg CO2·kg-1·h-1 lower than that of the control group (p < 0.05). CP treatment slowed down the decrease in the content of amino acids and volatile organic compounds (such as 2-methyl-4-pentenal, 2-hexenal, and 3-hexenal) in winter jujubes. This study will provide basic data for applying CP preservation technology in postharvest winter jujubes.

Characterization and biocontrol potential of Wickerhamomyces subpelliculosus yeasts isolated from dates: Volatile compounds-mediated antifungal activity against mycotoxigenic Penicillium strains

Seven yeast strains were isolated from Tunisian dates. The strains were identified by sequence analysis of the D1/D2 domain of the nuclear large subunit (LSU) rRNA gene. Based on this all strains in the study were almost identical with that of the type strain of Wickerhamomyces subpelliculosus (CBS 5767) indicating that they belong to this species. All strains were characterized physiologically and biochemically. All strains grew in the presence of 50 % sucrose, 10 % sodium chloride and at 42 °C. The potential of these yeasts as biocontrol agent against mycotoxigenic Penicillium species inhabiting date, was evaluated. All yeast strains inhibited the growth of P. citrinum P10 and P. chrysogenum C17 previously isolated from dates, with inhibition percentages ranging between 43.6 % and 70.3 % on dual culture plate assays. Moreover, the volatile compounds (VCs) produced by these yeasts inhibited the mycelial growth rate and sporulation of both fungus strains, up to 76.5 and 100 %, respectively, on inverted culture plate assay. The VCs of W. subpelliculosus strains Y4 and Y24, which exhibit strong inhibitory activity against toxigenic Penicillium, were determined by head-space solid-phase microextraction (HS-SPME) combined with gas chromatography coupled with mass spectrometry (GC–MS) analysis. Results revealed significant levels of alcohols (27.36 % for Y4 and 23.35 % for Y24) and esters (66.19 % for Y4 and 75.82 % for Y24). Their significant bioactivity, along with the lack of reported adverse effects on consumer health or the environment, makes them a sustainable and effective alternative to synthetic fungicides for the biocontrol of mycotoxigenic Penicillium affecting stored dates.

Conserved carotenoid pigmentation in reproductive organs of Charophyceae.

Sexual reproduction in Charophyceae abounds in complex traits. Their gametangia develop as intricate structures, with oogonia spirally surrounded by envelope cells and richly pigmented antheridia. The red-probably protectant-pigmentation of antheridia is conserved across Charophyceae. Chara tomentosa is, however, unique in exhibiting this pigmentation and also in vegetative tissue. Here, we investigated the two sympatric species, C. tomentosa and Chara baltica, and compared their molecular chassis for pigmentation. Using reversed phase C30 high performance liquid chromatography (RP-C30-HPLC), we uncover that the major pigments are β-carotene, δ-carotene and γ-carotene; using headspace solid-phase microextraction coupled to gas chromatography equipped with a mass spectrometer (HS-SPME-GC-MS), we pinpoint that the unusually large carotenoid pool in C. tomentosa gives rise to diverse volatile apocarotenoids, including abundant 6-methyl-5-hepten-2-one. Based on transcriptome analyses, we uncover signatures of the unique biology of Charophycaee and genes for pigment production, including monocyclized carotenoids. The rich carotenoid pool probably serves as a substrate for diverse carotenoid-derived metabolites, signified not only by (i) the volatile apocarotenoids we detected but (ii) the high expression of a gene coding for a cytochrome P450 enzyme related to land plant proteins involved in the biosynthesis of carotenoid-derived hormones. Overall, our data shed light on a key protection strategy of sexual reproduction in the widespread group of macroalgae. The genetic underpinnings of this are shared across hundreds of millions of years of plant and algal evolution. This article is part of the theme issue 'The evolution of plant metabolism'.

Influences of lactic acid bacteria strains on the flavor profiles, metabolites and quality characteristics of red yeast rice produced by solid-state fermentation

Red yeast rice (RYR) as a traditional fermented food produced by inoculation of the Monascus genus into steamed rice through solid-state fermentation, has been used intensively for thousands of years in China. Herein, we investigated the flavor profiles, metabolites and quality characteristics of RYR produced by mix fermentation with lactic acid bacteria (LAB) using the headspace solid phase microextraction gas chromatography–mass spectrometry (HS–SPME–GCMS) approach integrated with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS). 56 volatile organic compounds (VOCs) and 1287 non-volatile metabolites were identified and classified into eight classes, the inoculation of Lactiplantibacillus plantarum (LP) and Limosilactobacillus fermentum (LF) increased VOCs and enhanced the flavor characteristics of RYR, with LP being the more significant. The KEGG pathway enrichment analysis revealed that most of the differential metabolites were enriched in amino acid metabolism when integrating volatile and non-volatile omics data, meanwhile, the addition of LAB promoted the metabolism of amino acid, alcohols, fatty acid and some flavonoids, in particular, amino acid metabolism was almost upregulated in the LP group. Therefore, this study highlights the tremendous potential of LAB in improving the flavor quality of RYR. This study provides novel insights into RYR fermentation processes and establishes a theoretical foundation for developing and applying new RYR products.

Comparative analysis of aroma profiles in walnut, pecan and hickory nuts during the roasting process using E-nose, HS-SPME-GC-MS, and HS-GC-IMS

Walnut, pecan, and hickory nuts are well known for their nutritional value and health benefits, with consumption having increased significantly in recent years. Outstanding aroma is an important indicator for nut quality evaluation. However, the impacts of thermal processing on their aroma formation are not well understood. To address this gap, a comprehensive analysis of the aroma profiles were conducted during the roasting process using both sensory evaluation and advanced analytical equipment, including an electronic nose (E-nose), headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The results indicated that thermal processing had a substantial effect on the sensorial characteristics of the nuts, with hickory nuts exhibiting a distinct nutty aroma compared to walnuts. HS-SPME-GC-MS analysis further identified 118 volatile organic compounds (VOCs), encompassing 33 heterocyclic compounds, 18 aldehydes, 11 aromatics, 18 ketones, and other compounds, while HS-GC-IMS analysis detected 63 volatile compounds. Notably, the roasting process led to the reduction in alcohols and acids, while simultaneously caused the increase of esters, ketones, pyrazines, and phenols, all of which are crucial for the development of nut aroma. Especially, some components like 1-Octanol, 2-Pentyl-furan, Hexanal, Acetylpyrazine, Benzophenone, and Octyl ester may contribute to unique odors of pecan and hickory nuts. These findings provide valuable insights into the flavor formation of the three nuts and the optimization of roasting process.

Comprehensive characterization of volatile compounds in Iranian black teas using chemometric analysis of GC-MS fingerprints

Black tea, a widely popular non-alcoholic beverage, is renowned for its unique aroma and has attracted significant attention due to its complex composition. However, the chemical profile of Iranian tea remains largely unexplored. In this research, black tea samples from key tea cultivation regions in four geographical areas in northern Iran were firstly analyzed using headspace solid-phase microextraction followed by gas chromatography–mass spectrometry (HS-SPME-GC–MS) to separate, identify, and quantify their volatile organic compounds. Subsequently, employing a robust investigative strategy, we utilized for the first time the well-known multivariate curve resolution-alternating least square (MCR-ALS) method as a deconvolution technique to analyze the complex GC–MS peak clusters of tea samples. This approach effectively addressed challenges such as severe baseline drifts, overlapping peaks, and background noise, enabling the identification of minor components responsible for the distinct flavors and tastes across various samples. The MCR-ALS technique significantly improved the resolution of spectral and elution profiles, enabling both qualitative and semi-quantitative analysis of tea constituents. Qualitative analysis involved comparing resolved peak profiles to theoretical spectra, along with retention indices, while semi-quantification was conducted using the overall volume integration (OVI) approach for volatile compounds, providing a more accurate correlation between peak areas and concentrations. The application of chemometric tools in GC–MS analysis increased the number of recognized components in four tea samples, expanding from 54 to 256 components, all with concentrations exceeding 0.1 %. Among them, 32 volatile compounds were present in every tea sample. Hydrocarbons (including alkenes, alkanes, cycloalkanes, monoterpenes and sesquiterpenes), esters and alcohols were the three major chemical classes, comprising 78 % of the total relative content of volatile compounds. Analyzing black teas from four distinct regions revealed variations not only in their volatile components but also in their relative proportions. This integrated approach provides a comprehensive understanding of the volatile chemical profiles in Iranian black teas, enhances knowledge about their unique characteristics across diverse geographical origin, and lays the groundwork for quality improvement.

Exploration of Volatileomics and Optical Properties of Fusarium graminearum-Contaminated Maize: An Application Basis for Low-Cost and Non-Destructive Detection.

Fusarium graminearum (F. graminearum) in maize poses a threat to grain security. Current non-destructive detection methods face limited practical applications in grain quality detection. This study aims to understand the optical properties and volatileomics of F. graminearum-contaminated maize. Specifically, the transmission and reflection spectra (wavelength range of 200-1100 nm) were used to explore the optical properties of F. graminearum-contaminated maize. Volatile organic compounds (VOCs) of F. graminearum-contaminated maize were determined by headspace solid phase micro-extraction with gas chromatography-tandem mass spectrometry. The VOCs of normal maize were mainly alcohols and ketones, while the VOCs of severely contaminated maize became organic acids and alcohols. The ultraviolet excitation spectrum of maize showed a peak redshift as fungi grew, and the intensity decreased in the 400-600 nm band. Peak redshift and intensity changes were observed in the visible/near-infrared reflectance and transmission spectra of F. graminearum-contaminated maize. Remarkably, optical imaging platforms based on optical properties were developed to ensure high-throughput detection for single-kernel maize. The developed imaging platform could achieve more than 80% classification accuracy, whereas asymmetric polarization imaging achieved more than 93% prediction accuracy. Overall, these results can provide theoretical support for the cost-effective preparation of low-cost gas sensors and high-prediction sorting equipment for maize quality detection.

Comparison of water quality, planktonic community, and volatile organic compounds in the seawater from five cage culture areas of large yellow croaker

The rapid development of marine fish cage farming has led to ecological damage, adversely affecting fish quality. Significant regional quality differences in large yellow croaker under similar farming conditions suggest that the water environment plays a crucial role in fish quality. Using full-length18s/16 s rRNA sequencing with bacterial absolute quantity and headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC–MS), we investigated the planktonic community and volatile organic compounds (VOCs) in seawater from cages housing large yellow croaker at five major mariculture sites in China, including ND (26.627°E, 119.638°N), NJ (27.479°E, 121.052°N), DT (27.981°E, 121.196°N), NC (28.470°E, 121.907°N), and DJ (30.198°E, 122.698°N). Notably, three dominant ciliates, Mesodinium rubrum, Strombidium sp., and Pseudotontonia simplicidens, were identified in NJ as bioindicators for water quality. Additionally, NJ cages had the highest bacterial biomass with 54 % Synechococcus CC9902, and the lowest abundance of bacteria with pathogenic activities. These may explain NJ's optimal water quality parameters and the highest eukaryotic biodiversity. In contrast, DT and DC contained only the core ciliate M. rubrum, with no dominant ciliate in ND. Styela gibbsii, a filter feeder, predominated in ND cages, adhering to the net. The occurrence of red tide-causing species and pathogenic bacteria or fungi was notable in DJ, DC, DT, and ND, including Akashiwo sanguinea, an unclassified Dinophyceae, Gyrodinium fusiforme, Pirum gemmate, Candida parapsilosis, Hortaea werneckii, and Pseudomonas juntendi. Bacterial functional analysis showed that ND cages harbored unique strains linked to ureolysis and various pathogenic activities. Co-association networks suggested that 2,4-Di-tert-butylphenol and pentadecane might play roles in communication within plankton communities. A rise in pleasant VOCs such as acetyl valeryl, pentadecane, butyl butyrate, tetradecane, and 5-butyldihydro-2(3H)-furanone was observed in DJ, DC, DT, and NJ, compared to ND. The results provide valuable insights for improving aquaculture practices and mitigating environmental impacts. The results provide valuable bioindicators for monitoring water quality using microbial communities and VOC profiles.

Comparative Study on Morphological Features and Chemical Components of Wild and Cultivated Angelica sinensis Based on Bionic Technologies and Chemometrics.

As a traditional Chinese medicine, Angelica sinensis is primarily sourced from cultivated plants due to the significant decline in wild resources. This shift raises concerns about potential differences in efficacy resulting from variations in morphological features and chemical composition between wild (WA) and cultivated (CA) A. sinensis. In this study, a suite of advanced analytical techniques including electronic nose, electronic tongue, and electronic eye, alongside headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry and high-performance liquid chromatography, was applied to compare the morphological features and chemical components of WA and CA. Furthermore, principal component analysis and partial least-squares discriminant were employed for data analysis. The morphological features and chemical components of WA and CA were compared and analyzed. The results showed that three bionic technologies can distinguish WA from CA well and that fusion signals can distinguish better. There were differences between WA and CA in odor, taste, color, and content of the indicator components. There were correlations between the morphological features and the content of indicator components.

Characterization of the Geographical Origin of the Traditional Chinese Fermented Soybean Douchi by Gas Chromatography-Mass Spectrometry (GC-MS) and Chemometrics

Douchi is a highly appreciated product due to its unique flavor, high nutritional value, and health benefits. Douchi from different regions exhibits distinct characteristics. The objective of this study was to investigate the volatile profiles in douchi produced from different geographical origins using gas chromatography-mass spectrometry (GC-MS) and chemometrics. The volatiles were extracted by headspace solid-phase micro-extraction (HS-SPME) and subsequently determined by GC-MS. A comparative analysis was further conducted to identify the variations in volatile compounds among the samples. The correlation between the samples was investigated by employing cluster analysis (CA) and principal component analysis (PCA). An orthogonal partial least squares-discriminant analysis (OPLS-DA) model was established to discriminate samples from different regions and identify key differential compounds. A total of 46 volatile compounds were detected, among which terpenes, alcohols were the main compounds. Furthermore, 14 key differentiating compounds were screened out based on the OPLS-DA modle. The application of GC-MS combined with chemometrics offers a theoretical framework for douchi quality control and classification.

Unraveling Shengmuxiang in Jiang-flavor base baijiu using a combination of metabolomics and sensomics strategy

Shengmuxiang (SMX), an important aroma in Jiang-flavor base baijiu, significantly influences the quality of the product. This study employed untargeted metabolomics combined with sensomics to explore the key compounds responsible for SMX. Results indicated that SMX samples had higher intensities of green and woody-like odors compare to control samples. A total of 87 aroma compounds were identified by headspace solid phase microextraction combined with gas chromatography–mass spectrometry technology. Based on the variable projection importance, PCA and OPLS-DA were employed to identify 22 potential marker compounds. Quantitative results combined with hierarchical cluster and OAV analysis revealed that 9 aroma compounds (OAV > 1) had high concentrations in SMX samples. Aroma recombination and omission experiments further indicated that acetaldehyde and acetal were the key compounds responsible for the characteristic aroma of SMX in Jiang-flavor base baijiu. These findings provide valuable insights into the distinct aroma profile of SMX and offer a basis for quality control of Jiang-flavor base baijiu.