Headspace Solid-phase Microextraction-gas Chromatography-mass Spectrometry Research Articles

Effects of temporary rearing with organic selenium on the muscle flavor and texture properties of largemouth bass (Micropterus salmonides)

In this study, the influences of organic selenium (Se, 0.002 mg/L) on the muscle flavor and texture properties of Micropterus salmonides under fasting temporary rearing (8 weeks) was investigated. Electronic nose and headspace solid-phase microextraction-gas chromatography–mass spectrometry analysis suggested that organic Se regulated the types and contents of volatile compounds, especially aldehydes and ketones, which were increased in the early temporary rearing but decreased in the late stage. Organic Se significantly increased the content of 5′-inosine monophosphate by approximately 15 % (p < 0.05), and decreased the content of hypoxanthine and hypoxanthine ribonucleoside by more than 20 % (p < 0.05). After the 8th temporary rearing week, muscle hardness and springiness increased by at least 10 % (p < 0.01), resilience and gumminess improved by at least 18 % (p < 0.05) and 5.9 % (p < 0.05), respectively. In conclusion, organic Se ameliorates the flesh quality of M. salmonides during long-term temporary rearing.

The Antimicrobial Activity and Characterization of Bioactive Compounds in Peganum harmala L. Based on HPLC and HS-SPME-GC-MS.

Peganum harmala L. is a perennial herb of the Tribulus family and its aerial parts and seeds can be used as medicine in the traditional medicine of China. However, the differences in chemical components and antibacterial activity between different parts have not been reported. In this study, the chemical composition of the different parts of P. harmala was characterized by high-performance liquid chromatography (HPLC) and headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The antimicrobial activities of the different parts and some isolated components were also carried out on 12 bacterial strains and phytopathogenic fungi. The HPLC results revealed that the contents of harmine and harmaline in the seeds were higher than that in the aerial parts. A total of 94 volatile organic compounds (VOCs) were tentatively identified by HS-SPME-GC-MS for the first time. The major components were methyl hexadecanoate, p-xylene, octane, (Z)-9-octadecanoate, ethylbenzene, methyl octadecanoate, ethyl hexadecanoate, and methyl tetradecanoate. At the concentration of 800 μg·mL−1, the methanol extracts of seeds showed stronger antimicrobial activities with a wide antimicrobial spectrum, inhibiting Escherichia coli (ATCC 24433), Xanthomonas oryzae (ACCC 11602), and Xanthomonas axonopodis with inhibitory rates of more than 90%. Furthermore, harmine and harmaline showed better antibacterial activities against all the bacteria. These findings indicated that alkaloids from P. harmala could account for antimicrobial activity, which could be used as lead molecules in the development of new antimicrobial drugs.

HS-SPME-GC/MS Analysis for Revealing Carob's Ripening.

Carob’s recognized nutritional and medicinal value next to its unique agriculture importance is associated with an array of social, economic, and cultural activities. The carob fruit is popular for its intense aroma due to the emitted volatile organic compounds (VOCs). The composition of VOCs released from carob fruits changes during ripening, rendering it a non-invasive tool for the determination of the ripening period and freshness of the fruit. Therefore, headspace solid-phase microextraction gas chromatography/mass spectrometry (HS-SPME-GC/MS) was applied to reveal the respective gaseous signal molecules related to fruit maturity. The sampling was implemented during weeks 26–36 from five different locations in Cyprus. Additionally, the gaseous emissions of total VOCs (TVOCs) and carbon dioxide (CO2) were recorded next to the moisture content of the fruit. The major chemical classes in the ripening are acids, followed by esters, and ketones. More specifically, the most abundant VOCs during ripening are propanoic acid, 2-methyl-(isobutyric acid), 2-heptanone, propanoic acid, 2-methyl-, 2-methylbutyl ester, acetic acid, methyl isobutyrate, propanoic acid, 2-methyl-, 3-methylbutyl ester, 2-pentanone, butanoic acid and propanoic acid, 2-methyl-ethyl ester. Finally, CO2 emissions and moisture content showed a rapid decline until the 31st week and then stabilized for all examined areas. The methodology revealed variations in VOCs’ profile during the ripening process.

Discrimination and Characterization of the Volatile Organic Compounds in Schizonepetae Spica from Six Regions of China Using HS-GC-IMS and HS-SPME-GC-MS

Volatile organic compounds (VOCs) are the main chemical components of Schizonepetae Spica (SS), which have positive effects on the quality evaluation of SS. In this study, HS-SPME-GC-MS (headspace solid-phase microextraction-gas chromatography-mass spectrometry) and HS-GC-IMS (headspace-gas chromatography-ion mobility spectrometry) were performed to characterize the VOCs of SS from six different regions. A total of 82 VOCs were identified. In addition, this work compared the suitability of two instruments to distinguish SS from different habitats. The regional classification using orthogonal partial least squares discriminant analysis (OPLS-DA) shows that the HS-GC-IMS method can classify samples better than the HS-SPME-GC-MS. This study provided a reference method for identification of the SS from different origins.

Comparative Analysis of Flavor, Taste, and Volatile Organic Compounds in Opossum Shrimp Paste during Long-Term Natural Fermentation Using E-Nose, E-Tongue, and HS-SPME-GC-MS.

The present study focused on the determination of color, flavor, taste, and volatile organic compounds (VOCs) changes of shrimp paste fermented for 1, 2, 3, and 8 years by E-nose, E-tongue, and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). During fermentation, the color of shrimp paste turned dark brown with decreases in L*, a*, and b* values. Inorganic sulfide odor was dominant in all fermented samples. The umami, richness, and aftertaste-B reached a maximum in year 3 of fermentation. A total of 182 volatiles, including long-chain alkanes, esters, aldehydes, olefins, ketones, acids, furans, and pyrazines, were detected. Sixteen VOCs including dimethyl disulfide, methional, trimethyl-pyrazine, (E,E)-2,4-heptadienal, benzeneacetaldehyde were selected as flavor markers. Correlation analysis showed that 94 VOCs were related to saltiness while 40, 17, 21, 22, and 24 VOCs contributed to richness, umami, aftertase-B, sourness, and bitterness, respectively. These novel data may help in optimizing fermentation duration to achieve target flavor indicators in opossum shrimp paste production.

Characterization of the volatile flavor profiles of Zhenjiang aromatic vinegar combining a novel nanocomposite colorimetric sensor array with HS-SPME-GC/MS

In this work, the feasibility of combining headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS) with colorimetric sensor array (CSA) for flavor characterization of Zhenjiang aromatic vinegar (ZAV) from different grades was evaluated. Firstly, a new type of nanocomposite CSA that combines porous nanomaterials including hollow zeolitic imidazolate framework-8 (H-ZIF-8) and Universitetet i Oslo-66-NO2 (UiO-66-NO2) with chemically responsive dyes was successfully constructed. Then, the nanocomposite CSA was applied to effectively discriminate ZAV of different grades and further quantitively predict the characteristic aroma components by using multivariate data analysis. Compared with other pattern recognition methods, support vector machine (SVM) model achieved the highest recognition rate both for training set (100%) and prediction set (94.44%). Furthermore, a good performance of quantitative prediction of characteristic aroma components of ZAV including acetic acid, total volatile acids, furfural, aldehyde ketones, ethyl acetate and esters combining CSA with partial least square (PLS) regression was achieved with all the correlation coefficients being over 0.80 for training and prediction sets. Therefore, the nanocomposite CSA combined with chemometrics could be an effective tool for the rapid and nondestructive assessment of flavor and quality of vinegar.

Evaluation of aroma characteristics in grass carp mince as affected by different washing processes using an E-nose, HS-SPME-GC-MS, HS-GC-IMS, and sensory analysis

The aroma characteristics of grass carp mince washed in four processes were analyzed via electronic nose (E-nose), headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and sensory analysis techniques. Significant differences were revealed in the E-nose and sensory analysis results of the aroma characteristics of grass carp mince samples washed via different washing processes, while fifty-seven volatile compounds (thirteen aldehydes, eighteen alcohols, two ketones, eighteen hydrocarbons, two aromatic compounds, one furan, and two other compounds) and twenty volatile compounds (five aldehydes, four ketones, six alcohols, four esters, and one acid) were identified via HS-SPME-GC-MS and HS-GC-IMS of the Raw and washed grass carp mince samples, respectively. All these techniques revealed that the types and relative contents of volatile compounds in the grass carp mince decreased significantly and differently after each of the four washing processes. Moreover, compared with the water and saline solution washing processes, washing with weak alkaline solution processes exhibited the most significant removal effect on the volatile compounds of grass carp mince. Besides, the sensory analysis results also showed that weak alkaline solution washing processes (washing twice with pure water and once with 0.3% sodium bicarbonate solution) may be most effective in removing fishy off-odor compounds and contributing to a better overall aroma profile in grass carp mince. The findings of this study may provide some basic knowledge for the rational screening of washing methods in the production of high-quality grass carp surimi.

Antifungal Activity of Volatile Organic Compounds from Bacillus velezensis CE 100 against Colletotrichum gloeosporioides

Colletotrichum gloeosporioides is the most prevalent phytopathogen, causing anthracnose disease that severely affects the production of various fruit trees, including walnut and jujube. In this study, the volatile organic compounds (VOCs) from Bacillus velezensis CE 100 disrupted the cell membrane integrity of C. gloeosporioides and reduced the spore germination by 36.4% and mycelial growth by 20.0% at a bacterial broth concentration of 10%, while the control group showed no antifungal effect. Based on the headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) analysis, seven VOCs were identified from the headspace of B. velezensis CE 100. Out of the seven VOCs, 5-nonylamine and 3-methylbutanoic acid were only detected in the headspace of B. velezensis CE 100 but not in the control group. Both 5-nonylamine and 3-methylbutanoic acid showed significant antifungal activity against the spore germination and mycelial growth of C. gloeosporioides. Treatment with 100 µL/mL of 5-nonylamine and 3-methylbutanoic acid suppressed the spore germination of C. gloeosporioides by 10.9% and 30.4% and reduced mycelial growth by 14.0% and 22.6%, respectively. Therefore, 5-nonylamine and 3-methylbutanoic acid are the potential antifungal VOCs emitted by B. velezensis CE 100, and this is the first report about the antifungal activity of 5-nonylamine against C. gloeosporioides.

Comprehensive Flavor Analysis of Volatile Components During the Vase Period of Cut Lily (Lilium spp. 'Manissa') Flowers by HS-SPME/GC-MS Combined With E-Nose Technology.

Volatile compounds could affect the flavor and ornamental quality of cut flowers, but the flavor change occurring during the vase period of the cut flower is unclear. To clarify the dynamic changes during the vase period of cut lily (Lilium spp. ‘Manissa’) flowers, comprehensive flavor profiles were characterized by the electronic nose (E-nose) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS). The response value of sensor W2W was significantly higher than other sensors, and its response value reached the highest on day 4. A total of 59 volatiles were detected in cut lilies by HS-SPME/GC-MS, mainly including aldehydes, alcohols, and esters. There were 19 volatiles with odor activity values (OAVs) greater than 1. Floral and fruity aromas were stronger, followed by a pungent scent. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) could effectively discriminate lily samples derived from different vase times on the basis of E-nose and HS-SPME-GC-MS. In summary, our study investigates the flavor change profile and the diversity of volatile compounds during the vase period of cut lilies, and lilies on day 4 after harvest exhibited excellent aroma and flavor taking into consideration of the flavor intensity and diversity. This provided theoretical guidance for the assessment of scent volatiles and flavor quality during the vase period of cut lily flowers and will be helpful for the application of cut lilies during the postharvest process.

Analysis of floral differences in terpenoids between two genotypes of Jerusalem artichoke (Helianthus tuberosus L.) by HS-SPME-GC/MS-based on the metabolome and transcriptome

Jerusalem artichoke (Helianthus tuberosus L.) bears flowers with bright colors and diverse fragrances. It can be used for greening, and brewing flower tea, and has great ornamental and edible values. However, little is known about the floral components and genetic differences in their biosynthetic processes. In this study, we detected the floral components of two Jerusalem artichoke flowers having different fragrances by headspace solid-phase microextraction gas chromatography/mass spectrometry (HS-SPME-GC/MS), along with the analysis of related pathways of differential metabolites, differential expression genes (DEGs) and terpenoid biosynthesis. The results showed that 201 metabolites, primarily monoterpenoids and sesquiterpenoids, were detected in JA192 and JA399. Among them, most terpenoids were found in metabolites and their relative contents of JA399 were significantly higher than those of JA192. Safranal and rimuene were unique components of JA399. The combined transcriptomic and metabolomic analyses showed that among the JA192 and JA399, gcpE1, gcpE2, IDI1, and IDI2 genes were the key genes in the biosynthetic pathway of (+)-α-pinene, (-)-β-pinene and safranal. DXS1 gene played an important role in the biosynthetic pathway of rimuene. IDI1, IDI2, HMGR3, and HMGS1 genes played positive roles in the biosynthetic pathway of β-copaene and (+)-δ-cadinene. In summary, differences in terpenoids and their contents were the major factors responsible for the differences in floral components between the two genotypes of Jerusalem artichoke. These were associated with DEGs related to terpenoid synthesis.

Effects of microbial community structure and its co-occurrence on the dynamic changes of physicochemical properties and free amino acids in the Cantonese soy sauce fermentation process

The soy sauce produced by Cantonese fermentation has a unique flavor, among which brine fermentation plays an important role. In this fermentation process, 61 volatile compounds, including 19 esters, 10 aldehydes, 9 alcohols, 5 phenols, and 18 others, were identified by headspace solid-phase microextraction–gas chromatography–mass spectrometry. Seventeen kinds of free amino acids were detected by high-performance liquid chromatography. Results showed that Touyou, which comprised 1.5 g/100 g total nitrogen, 1.0 g/100 mL amino acid nitrogen, 3.66 g/100 g reducing sugar, 1.44 g/100 mL total acid, 17.04 g/100 mL salt content, and 27.3% umami free amino acids, had excellent quality. High-throughput sequencing was used to identify microorganisms. The top 3 of bacteria were Weissella, Staphylococcus, and Lactobacillus, and the top 3 fungi were Aspergillus, Zygosaccharomyces, and Candida. The co-occurrence network analysis of microorganisms showed that the top-ranked microorganisms were Plectosphaerella, Aureobasidium, unidentified_Mortierellales_sp, Glutinomyces, Faecalibacterium, and Cladophialophora. Then, eight microorganisms (VIP[pred] > 1) were obtained by two-way orthogonal partial least squares model, namely, Staphylococcus, Candida, Weissella, Aspergillus, Zygosaccharomyces, Lactobacillus, Monilinia, and Clavispora. Correlation analysis showed that these microorganisms were strongly related to flavor metabolites. This study explored the dynamics of traditional Cantonese fermentation, which has positive implications for optimizing this traditional fermentation process.

Influence of cane and beet sugar for second fermentation on “fruity” aromas in Auxerrois sparkling wines

Traditional Method sparkling wine production requires a sugar addition to the base wine to initiate the second alcoholic fermentation in bottles. This study aimed to identify differences in “fruity” volatile aroma compounds (VOCs) in Traditional Method sparkling wines produced from the addition of either cane sugar or beet sugar to Auxerrois base wines. Wines underwent a second fermentation in bottles inoculated with IOC 18-2007 yeast and fermented at 15 °C. Standard chemical analysis was carried out on base wines and sparkling wines. The concentrations of fourteen “fruity” volatile aroma compounds representing five classes of compounds were analysed by Headspace-Solid-Phase Micro-Extraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). Cane and beet sugars were analysed in de-aromatised wine and distilled water to establish the concentrations of VOCs present in the sugar products prior to addition to wine. Wines were analysed on the day of inoculation and bottling and again after the second fermentation. Beet sugar significantly (Pt &lt; 0.05) increased the concentration of linear fatty acid-derived ethyl esters (ethyl octanoate, ethyl hexanoate, and ethyl butyrate) compared to cane sugar in sparkling wine. These results are attributed to higher concentrations of medium-chain fatty acids found in beet sugar due to the duration of sugar beet storage prior to processing. Recommended future research includes monitoring aroma compounds during ageing on lees, sensory analysis, and an investigation of a wider range of sugar products permitted for use in sparkling wine production.

Effect of low-temperature thermal drying on malodorous volatile organic compounds (MVOCs) emission of wastewater sludge: The relationship with microbial communities

Sludge treatment processes are the main source of nuisance odors in wastewater treatment plants. Apart from well-known odorants such as NH3 and H2S, malodorous volatile organic compounds (MVOCs) contribute largely to nuisance odors but are less concerned. In this work, the emission of MVOCs from wastewater sludges at different processing stages was measured, and the effects of dewatering and low-temperature thermal drying on the generation of sludge odor were investigated. The MVOCs were analyzed by olfactory measurements, headspace gas chromatography-coupled ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). Low-temperature thermal drying treatment changed the odor categories and increased the odor intensity (OI) from moderate level (8–9) for raw sludges to strong (>10) for dried sludge. The odor emission capacity of MVOCs, namely the concentration of MVOCs, increased for dried sludge. The major odorants of sludge after different processes included 2-MIB, geosmin, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), hexanal, and decanal according to their odor activity values (OAVs). The bacterial community structures showed a correlation with the key MVOC odorants. Specifically, there was a significant positive correlation between the concentration of key odorants and the relative abundance of the phyla of Actinobacteria and Chloroflexi. Thus, low-temperature thermal drying had a significant effect on odor formation by acting on the microbial community of sludge.

Comparison of volatile compounds and fatty acids of jujubes (Ziziphus jujuba mill.) before and after blackening process

ABSTRACT Blackened jujube, as an emerging fruit processed product, was obtained from red jujube by a blackening processing of Maillard reaction with high humidity and temperature. This study was to compare the volatile compounds (VOCs) and fatty acids (FAs) between red jujubes (RJs) and blackened jujubes (BJs) of six cultivars (JZ, MZ, JSXZ, HZ, YHDZ and TZ) using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and GC-MS respectively. A total of 56 VOCs were detected in these six cultivars (RJs and BJs), and their types and contents were analyzed. A total of 22 FAs, including 12 saturated fatty acids (SFAs) and 10 unsaturated fatty acids (USFAs), was determined in the RJs and BJs, The content of essential FAs in BJs was higher. B-JZ had the greatest increase in linoleic and ɑ-linolenic from 5.3 mg/100 g to 10.0 mg/100 g and from 3.4 mg/100 g to 5.1 mg/100 g, respectively. It indicated that JZ is better for improving flavor and the composition of FAs by blackening process than other five cultivars. In addition, FAs and VOCs were found to have a linear correlation with color. The types of VOCs and FAs between red and blackened jujubes were also discriminated using principal component analysis (PCA).

Effect of Natural Antioxidants from Marigolds (Tagetes erecta L.) on the Oxidative Stability of Soybean Oil.

In recent years, synthetic antioxidants that are widely used in foods have been shown to cause detrimental health effects, and there has been growing interest in antioxidants realised from natural plant extracts. In this study, we investigate the potential effects of natural antioxidant components extracted from the forage plant marigold on the oxidative stability of soybean oil. First, HPLC-Q-TOF-MS/MS was used with 1,1-diphenyl-2-picrylhydrazyl (DPPH) to screen and identify potential antioxidant components in marigold. Four main antioxidant components were identified, including quercetagetin-7-O-glucoside (1), quercetagetin (2), quercetin (3) and patuletin (4). Among them, quercetagetin (QG) exhibited the highest content and the strongest DPPH radical scavenging activity and effectively inhibited the production of oxidation products in soybean oil during accelerated oxidation, as indicated by reductions in the peroxide value (PV) and acid value (AV). Then, the fatty acids and volatile compounds of soybean oil were determined with gas chromatography–mass spectrometry (GC-MS) and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS). A total of 108 volatile components, including 16 alcohols, 23 aldehydes, 25 ketones, 4 acids, 15 esters, 18 hydrocarbons, and 7 other compounds, were identified. QG significantly reduced the content and number of aldehydes and ketones, whereas the formation of acids and hydrocarbons was completely prevented. In addition, the fatty acid analysis demonstrated that QG significantly inhibited oxidation of unsaturated fatty acids. Consequently, QG was identified as a potential, new natural antioxidant that is believed to be safe, effective and economical, and it may have potential for use in plant extracts feed additives.

Combined Straw and Plastic Film Mulching Can Increase the Yield and Quality of Open Field Loose-Curd Cauliflower.

To evaluate the impact of straw mulching on the production of open field loose-curd cauliflower, this study analyzed the “Feicui No.9” cauliflower variety, grown in field trials in Northwest China, in 2019 and 2020. Plots in an open field were prepared without mulch (CK1) and with plastic film mulch (CK2), as experimental controls, along with three experimental mulching methods, including dual straw and plastic film mulch (T1), inter-row straw mulch (T2), and full straw mulch (T3). The effects of the different ground cover alternatives on loose-curd cauliflower's dry matter accumulation, yield, quality, and volatile compounds, were explored. The results showed that, compared with CK2 treatment, T1 treatment promoted the accumulation of dry matter, and increased the economic and biological yield, by 12.98 and 6.51%, respectively. The soluble sugar and vitamin C content in loose-curd cauliflower heads, subjected to T1 treatment, increased by 18.46 and 8.12%, respectively, and the nitrate content decreased by 25.57%. Moreover, the T1, T2, and T3 treatments significantly increased the levels of macro-, meso-, and microelements. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to determine the volatile substances in loose-curd cauliflower heads from the 2020 harvesting period. Detected compounds included 17 aldehydes, 15 ketones, 10 alcohols, 15 esters, 29 hydrocarbons, 12 nitrogen-containing compounds, and 17 other substances. T1, T2, and T3 treatments increased the volatile substance content, whereas T1 treatment increased the quantity of volatile substances. In summary, dual mulching with straw and plastic film could promote dry matter accumulation, significantly increase the yield and quality, and effectively improve the flavor of loose-curd cauliflower. This mulching technique can be applied to open field vegetable and corn production areas, providing technical and theoretical support for the realization of high-yield, high-quality production models and a new straw recycling method.

Authentication and quality evaluation of not from concentrate and from concentrate orange juice by HS-SPME-GC-MS coupled with chemometrics

Substituting of not from concentrate (NFC) orange juice with from concentrate (FC) orange juice is a novel adulteration problem. This study used headspace solid-phase microextraction-gas chromatography-mass spectrometry coupled with chemometrics to discriminate between NFC and FC orange juices. Twenty-five compounds were identified as differential compounds for NFC and FC orange juice discrimination. During processing, concentration treatment is a key step for forming differential compounds. After the treatment, 25 differential compounds decreased significantly. Among, trans-isopiperitenol (5.45 ± 0.79 μg/L), ethyl butanoate (106.5 ± 7.24 μg/L), butyl butanoate (3.60 ± 0.19 μg/L), hexyl butanoate (2.82 ± 0.14 μg/L), ethyl octanoate (5.04 ± 0.39 μg/L), 1,3,8-p-menthatriene (4.97 ± 0.49 μg/L), p-mentha-1,5,8-triene (4.82 ± 0.59 μg/L), and limona ketone (5.00 ± 0.53 μg/L) declined until they were undetectable. These 25 differential compounds can discriminate NFC and FC orange juices processed by thermal concentration and other sterilization methods. Based on the 25 differential compounds, a partial least squares discriminant analysis model was constructed to identify commercial samples. 100% NFC and 86.67% FC commercial orange juices were consistent with their labels. These results clarify the volatile differences in volatile compounds and their causes for NFC and FC orange juices and provide references for juice quality control.

Automated headspace solid-phase microextraction-gas chromatography-mass spectrometry of trihalomethane and typical nitrogenous disinfection by-products in water

Disinfection by-products (DBPs) are detrimental to public health owing to their carcinogenicity and mutagenesis. Fast and reliable determination of DBPs is essential for ascertaining their formation, characteristics, and occurrence. This study reported an automated headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for quantifying typical nitrogenous-DBPs, including haloacetonitriles (HANs), trichloronitromethane, and trihalomethanes (THMs). The analysis was further optimized by selecting SPME fiber coatings, extraction/desorption time and temperature, and salt addition. The optimized method examined the occurrence and stability of the selected DBPs in aqueous samples under different preservation conditions and showed good sensitivity (limit of detection: 0.010–0.320 µg/L) and precision. Most THMs and HANs with high recovery were preserved in ultrapure water under dark and low-temperature conditions. However, real samples exhibited greater analytical biases due to comprehensive effects of photochemistry, biochemistry, and physiochemistry. Based on the findings of this study, we recommend that tested samples should be preserved in a frozen state and analyzed within three days.

Characterization of the effect of different sugar on volatile flavor compounds of dried fish floss using e‐nose combined with HS‐SPME / GC‐MS

The aim of this study was to evaluate volatile compounds of dried fish floss with different sugar using electronic nose (e-nose) and headspace-solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS). Maillard reaction (MR) was carried out by reducing sugar (glucose, xylose, fructose, and galactose) instead of sucrose to increase the flavor of fish floss. The results showed that 64 volatile compounds were detected in fish floss. Hexanal, heptanal, nonanal, decanal, undecanal, tridecanal, pentadecanal, 4-ethyl-benzaldehyde, dodecanal, benzene acetaltaldehyde, (E, E)-2,6-nonadienal, (E, E)-2,4-decadienal, 2-undecanone, 1-octen-3-ol, (E)-2-hepten-1-ol, 1-heptanol, and 2-pentyl-furan were regarded as key volatile compounds. Furthermore, e-nose and partial least squares-discriminant analysis (PLS-DA) showed that there were significant differences in flavor among fish floss samples. The correlation analysis of browning index, fatty acids, and key volatile compounds confirmed that MR and lipid oxidation made a great contribution to the flavor formation. These results might provide guidance for the production and flavor formation of fish floss. Practical applications Dried fish floss deeply loved by the public is a traditional leisure food with unique odor and delicious taste. The attractive flavor of dried fish floss could be increased with the help of the Maillard reaction (MR). The type of sugar in MR has a great influence on the reaction process and the flavor of substances. The comprehensive information on the flavor among the dried fish floss with different sugar (sucrose, glucose, xylose, fructose, and galactose) was characterized by using HS-SPME/GC-MS, electronic nose (E-nose), and fatty acid analysis, which may provide a reference for the quality improvement of dried fish floss.

Aroma Profile and Phenolic Content of Honey Wine Produced from Wild Rose Fruit

In this study, two chromatographic techniques were applied to determine the aroma profile and phenolic compounds of “Honey wine” produced by addition of Wild Rose Fruits ( Rosa odorata -Andrews-Sweet). In addition, another control wine was produced with sucrose and rose fruits in order to differentiate compounds produced by yeast fermentation from those originated from honey and rose fruits. After maturation aroma components, phenolic compounds and sugar composition of wines were identified. Aroma components were determined by headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME/GC-MS) techniques in wine samples. The dominant aroma components in both wines were ethanol, ethyl acetate, isobutyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, ethyl caprylate, ethyl decanoate, capronate ethyl. Some minor differences in the percentage of major aroma components were determined between two wine samples. Phenolic and sugar compositions were identified by high performance liquid chromatographic (HPLC) method in fruit extract and wine samples. While the total amount of phenolic compounds were 3604.9 mg/l in fruit juice, 74.3 mg/l in control wine and 111.8 mg/l in honey wine, the most abundant phenolics in both wines were catechin, epicatechin and routine .