Volatile Extracts Research Articles

Chemical Composition of Volatile Extracts From Blackberries, Black Raspberries, and Blueberries and Their Apoptotic Effect on A549 Non-Small-Cell Lung Cancer Cells

ObjectivesBerry volatiles are responsible for the flavor and aroma of berries. Berry volatiles has been recently reported to have an anti-inflammatory effect. However, there is still limited information available on the health-promoting activities of berry volatiles. The objectives of this study were to evaluate the chemical composition of volatile extracts from blackberries, black raspberries, and blueberries and to investigate the anti-proliferative effect of three berry volatile extracts on A549 non-small-cell lung cancer cells and their mechanism. MethodsThe chemical composition of berry volatile extracts (BVEs) from blackberries (BK), black raspberries (BR), and blueberries (BU) were identified by using gas chromatography-mass spectrometry. A549 non-small cell lung cancer cells were treated with different dilutions (2-, 4-, and 8-fold dilutions) of three berry volatile extracts for 12, 24, and 48 h. The proliferation of A549 was measured by using an MTS assay. The induction of apoptosis and changes in the cell cycle by berry volatile extracts were analyzed by using a cell death detection ELISA kit and flow cytometry. All statistical tests were analyzed by using one-way ANOVA, followed by Tukey’s multiple comparisons. The significant difference was defined at P < 0.05. ResultsTotal volatiles in BK, BR, and BU volatile extracts were 1588.5 ± 170.9,3184.9 ± 75.3, and 3107.5 ± 256.4 μg/L, respectively. Among them, monoterpene was the most abundant compound in all three BVEs. All BVEs with two-fold dilution significantly induced apoptosis after 24 h (p < 0.05) and inhibited the proliferation of A549 after 48 h treatment (p < 0.05). In the cell cycle, the proportion of cells in G0/G1 interphase increased with two-fold diluted BVE treatments (64.9–73.1%) compared to control (60.3%) after 48 h. ConclusionsThese findings showed that berry volatile extracts from blackberries, black raspberries, and blueberries have the anti-proliferative effect on non-small lung cancer cells through apoptosis and possibly cell cycle arrest. This suggests that berry volatiles from blackberry, black raspberry, and blueberry may have a potential impact on lung cancer. Funding SourcesArkansas Biosciences Institute.

The Immunomodulatory Effects of Active Ingredients From Nigella sativa in RAW264.7 Cells Through NF-κB/MAPK Signaling Pathways.

Nigella sativa is a valuable herb for its functional compositions in both food and medication. N. sativa seeds can enhance immunity, anti-inflammation and analgesia and hypoglycemia, but most of the related researches are related to volatile oil and extracts, and the activity and mechanism of compounds is not clear. In this study, Ethyl-α-D-galactopyranoside (EG), Methyl-α-D-glucoside (MG), 3-O-[β-D-xylopyranose-(1 → 3)-α-L-rhamnose-(1 → 2)-α-L-arabinose]-28-O-[α-L-rhamnose-(1 → 4)-β-D-glucopyranose-L-(1 → 6)-β-D-glucopyranose]-hederagenin (HXRARG) and 3-O-[β-D-xylopyranose-(1 → 3)-α-L-rhamnose-(1 → 2)-α-L-arabinose]-hederagenin (HXRA) were isolated and identified from N. sativa seeds. In addition, four compounds could activate NF-κB pathway by promoting the expression of phosphorylation of P65 and IκBα, promoting the phosphorylation of JNK, Erk and P38 to activate MAPK signaling pathway, enhancing the proliferation and phagocytic activity of RAW264.7 cells, and promoting the release of NO, TNF-α and IL-6 on RAW264.7 cell in vitro. The results showed that N. sativa can be used as dietary supplement to enhance immune.

Behavioural and electrophysiological responses of Philaenus spumarius to odours from conspecifics

The meadow spittlebug, Philaenus spumarius L. (Hemiptera: Auchenorrhyncha: Aphrophoridae), is the main vector of Xylella fastidiosa subsp. pauca strain ST53, the causal agent of the Olive Quick Decline Syndrome. Philaenus spumarius and other Auchenorrhyncha are known to communicate via vibrations, whereas the possible occurrence of semiochemical communication has been poorly investigated so far. Through a chemical ecology approach, we provide evidence of intraspecific chemical communication in P. spumarius. In Y-tube olfactometer bioassays, males were attracted to unmated females as well as toward the headspace volatile extracts collected from unmated females. Conversely, females did not respond to unmated male volatiles or their extracts, nor did males and females respond to volatiles from individuals of the same sex. Electroantennography assays of unmated male and female headspace extracts elicited measurable responses in the antennae of both sexes. Male responses to body wash extracts from both sexes were stronger compared to female responses. Thus, suggesting the presence of compounds that are highly detected by the male’s olfactory system. The female head seemed to be the source of such compounds. This is the first record of intraspecific chemical communication in P. spumarius and one of the very few records in Auchenorrhyncha. Possible biological roles are under investigation.

Comparison of Extraction Techniques for the Determination of Volatile Organic Compounds in Liverwort Samples.

This article focuses on the comparison of four popular techniques for the extraction of volatile organic compounds (VOCs) from liverworts of the Calypogeia azurea species. Since extraction is the most important step in the sample analysis of ingredients present in botanical preparations, their strengths, and weaknesses are discussed. In order to determine the VOCs present in plants, selecting the appropriate one is a key step of the extraction technique. Extraction should ensure the isolation of all components present in the oily bodies of Calypogeia azurea without the formation of any artifacts during treatment. The best extraction method should yield the determined compounds in detectable amounts. Hydrodistillation (HD), applying Deryng apparatus and solid-liquid extraction (SLE), microwave-assisted extraction (MAE), and headspace solid-phase microextraction (HS-SPME) were used for volatile extraction. The extracts obtained were analysed by gas chromatography coupled to mass spectrometry (GC-MS) to determine the compounds.

Fan assisted extraction and HPLC-DAD-MS/MS identification of volatile carbonyl compounds as chemical descriptors of healthy and defective roasted coffee beans

In this work, the profile of the volatile carbonyl compounds in roasted coffee is performed. The assays focussed healthy coffee beans and the main typologies of defective beans (black, immature, sour and bored) of arabica and robusta species, roasted at light, medium and dark intensities. To perform the volatile compounds extraction, a fan-assisted extraction system was used. The experimental parameters temperature, sample treatment, sample mass and extraction period were evaluated. An efficient extraction of the volatile compounds could be accomplished after a 10 min period (RSD <10%). Twenty volatile carbonyl compounds were identified. Hexanal signal was of high intensity in roasted black beans. Butanal and 2-methylbutanal signals presented high intensity in sour and black robusta beans. Several compounds were of higher prevalence in healthy beans than in defective beans. Among them, furfural was considered the main indicator of healthy beans based on the highest signal difference observed between healthy and defective beans in arabica and robusta coffees at light, medium and dark roast degree.

New C9-polyacetylenes from the essential oil of the highly endangered species Baccharis palustris Heering (Asteraceae)

The essential oil composition of the aerial parts from Baccharis palustris Heering (Asteraceae), a highly endangered species, was analyzed by GC/qMS, GC/HRMS-TOF, FT-IR, UV–vis and NMR spectroscopy using 1D and 2D techniques. To our knowledge, this is the first report on the essential oil composition of B. palustris, as well as the first phytochemical study on this plant species. The volatile extracts were obtained from different phenologicals stages of plant, at flowering stage (FS) and vegetative stage (VS), where 51 components were identified accounting for 96.3 % and 99.0 % of the oil, respectively. The oil was rich in polyacetylene compounds (> 75 %), being the main components identified the new natural C9-polyacetylenes 1-nonene-3,5-diyne (1, here named as baccharisdiyne) (52.7–65.0 %), 1,7(Z)-nonadiene-3,5-diyne [2, 7(Z)-dehydro-baccharisdiyne] (14.4–17.8 %), and 1,7(E)-nonadiene-3,5-diyne [3, 7(E)-dehydro-baccharisdiyne] (1.5–2.4 %). In addition, the known polyacetylenic compounds (Z)-lachnophyllum acid methyl ester (4) (4.3–5.3 %) and (E)-lachnophyllum acid methyl ester (5) (0.2 %) were also identified. Moreover, GC/qMS analysis allowed the identification of other 46 components in the essential oil samples, mainly mono- and sesquiterpenoids. In B. palustris, C9-polyacetylenes probably derive biogenetically from a C10 precursor: baccharisdiyne (1) would be derived from either or both lachnophyllum methyl ester geometric isomers (4 or 5), by enzymatic hydrolysis followed by decarboxylation. Dehydro-baccharisdiynes (2 and 3) could be produced by a similar pathway starting from the corresponding matricaria acid methyl ester isomers, one of which was tentatively identified at trace-level in B. palustris essential oil.

Identification of Volatile Components of Flowers Of Zephyranthes Candida (Lindl.) Herb.

The volatile components of Zephyranthes candida flowers were extracted using headspace-solid phase micro-extraction (HS-SPME) technique and then were analyzed by gas chromatography-mass spectrometry (GC-MS) for the first time. The major compounds of volatile extract were found to be 1-hexanol (15.4%), methyl heptanoate (12.8%), hexyl acetate (4.9%), 2-acetyl pyrrole (3.6%), methyl-α-D-rhamnopyranoside (3.0%), phenethyl alcohol (2.8%), heptanoic acid (2.7%), and 1-octanol (2.1%). Bangladesh J. Bot. 51(1): 175-178, 2022 (March)

Antioxidant and Antiproliferation Activities of Lemon Verbena (Aloysia citrodora): An In Vitro and In Vivo Study.

Aloysia citrodora (Verbenaceae) is traditionally used to treat various diseases, including bronchitis, insomnia, anxiety, digestive, and heart problems. In this study, this plant’s antioxidant and anti-proliferation effects were evaluated. In addition to volatiles extraction, different solvent extracts were prepared. The GC-MS, LC-MS analysis and the Foline-Ciocalteu (F-C) method were used to investigate the phytochemical components of the plant. MTT assay was used to measure the antiproliferative ability for each extract. Antioxidant activity was determined using the 2,2-diphenylpicrylhydrazyl (DPPH) assay. In in vivo anti-proliferation experiments, Balb/C mice were inoculated with tumor cells and IP-injected with ethyl acetate extract of A. citrodora. After treatment, a significant reduction in tumor size (57.97%) and undetected tumors (44.44%) were obtained in treated mice, demonstrating the antiproliferative efficacy of the ethyl acetate extract. Besides, ethanol extract revealed the most potent radical scavenging effect. The findings of this study displayed that A. citrodora has promising cytotoxic and antioxidant activities. Still, further testing is required to investigate the extract’s chemical composition to understand its mechanisms of action.

Back Cover: Cover Image, Volume 21, Issue 2

The cover image is based on the Original Article Methods used for extraction of plant volatiles have potential to preserve truffle aroma: A review by Ranil Coorey et al., https://doi.org/10.1111/1541-4337.12927.

Optimization of Adsorption and Desorption Time in the Extraction of Volatile Compounds in Brewed Java Arabica Coffee Using the HS-SPME/GC-MS Technique

The headspace solid phase microextraction (HS-SPME) technique has been recognized as a reliable technique for characterizing the aroma profile of Arabica coffee beans. The amount and content of the detected volatile compounds depend on the volatile analyte extraction process with HS-SPME, namely the adsorption and desorption processes. However, the optimal extraction time in applying coffee volatile compounds is still limited. This research aimed to obtain the optimum adsorption and desorption time in analyzing volatile compounds in brewed Java Arabica coffee. The adsorption time was optimized for 20 to 60 minutes with 5 minutes desorption time. The desorption time was optimized from 5 to 45 minutes with a 20 minutes of adsorption time. There are 14 volatile compounds with a peak area percentage of more than 2% from adsorption and desorption optimization. The optimal adsorption time was 50 minutes, where there were 5 of 7 compounds with the most significant area, such as 2-furfural (29%), 2-acetyl furan (3%), 2-furfuryl acetate (6%), 5-methyl furfural (12%), and 2-furfuryl alcohol (14%). Meanwhile, the most optimal desorption time was 5 minutes which detected 12 compounds, while the other desorption time only detected eight compounds. Furfuryl formate (2%), pyridine (12%), and 2-furfuryl alcohol (14%) had a higher peak area than the other compounds at a desorption time of 5 minutes. The results showed the same number of volatile compounds at each adsorption time. In conclusion, the adsorption time did not affect the number of compounds detected as in the optimization of desorption time. Adsorption and desorption time is crucial in analyzing volatile compounds from coffee using the HS-SPME/GC-MS technique.

Methods used for extraction of plant volatiles have potential to preserve truffle aroma: A review.

Truffles are considered one of the world's most highly prized foods mainly due to their desirable organoleptic properties and rarity. However, truffles are seasonal (harvested mostly in winter from June to August in the Southern Hemisphere and from December to February in the Northern Hemisphere) and extremely perishable. Truffles deteriorate rapidly showing undesirable changes within 10days from harvest in aroma and visual appearance after harvest. The very short postharvest shelf life (about 7-10 days) limits the potential for export and domestic consumption all year round. Several preservation methods have been studied to prolong their shelf life without the loss of aroma. However, all traditional preservation techniques have their own shortcomings and remain challenging. The extraction of natural truffle aroma volatiles for food applications could be a potential alternative to replace the existing synthetic flavoring used for processed truffle products. Four commonly used extraction methods for recovering volatile compounds from plants, namely, supercritical carbon dioxide extraction, Soxhlet extraction, distillation, and cold pressing, are critically analyzed. Up to date, existing research about the extraction of aroma volatiles from truffles is limited in the literature but based on the volatility of the key truffle volatile compounds, supercritical carbon dioxide extraction may offer the best possibility so that a natural truffle-based product that can be used in food applications throughout the year can be made available.

CHEMICAL CHARACTERIZATION OF VOLATILE EXTRACT OF ARTEMISIA HERBA-ALBA AND STUDY OF ITS ANTIOXIDANT, ANTIMICROBIAL AND ANTIFUNGAL ACTIVITIES AND ITS INHIBITIONORY EFFECT ON CORROSION OF ALUMINUM IN HYDROGEN CHLORIDE SOLUTION

The chemical composition of the essential oil of Artemisia herba-alba obtained by hydrodistillation was determined by chromatographic analysis (GC and GC-MS). Seventy-nine components were identified, which accounted for 93.3% of the total essential oil. The major components were chrysanthenone (24.1 %), camphor (16,2%), α-thujone (12.8 %) and 1,8-cineole (9.3%). The investigated volatile extract showed potency antimicrobial activity, against all the studied bacterial strains (MIC values not exceeding 2 μg/mL). Also, this oil showed substantial antifungal activity MIC less than 0.5μg/mL for Fusarium oxysporum and Penicillium expansum. Compared to BHA and BHT which were acted as positive controls, the essential oil was the less active to inhibit the free radical DPPH insofar it failed to reach a scavenging capability of 50%. The oil was also tested for its corrosion inhibitor of pure aluminum in HCl (1 mol./L) using electrochemical techniques (potentiodynamic polarization, open circuit potential, and electrochemical impedance spectroscopy) and gravimetric measurements. The results reveal that the inhibition effectiveness was dose-dependent of the oil concentration (maximum corrosion inhibition = 94.3% for an optimal concentration of 0.8 g / L). These findings suggest that this essential oil may be a new green inhibitor agent against corrosion in hydrogen chloride solution media and could be used on food systems as an effective inhibitor of foodborne pathogens as well as for pharmaceutical applications.

Medicinal significance of drug-like compounds derived from Anethum sowa L. seed oil and in-silico predictive investigation of cancer therapy potential

Anethum sowa L. is an annual sweet-smelling herb recognized for gastronomic besides therapeutic usage since primeval times. Chemical configuration and the medicinal utility of seed essential oil of this herb grown in South Karnataka is limited; furthermore, the volatile oil and extract has not been deliberated or compared for its out-turn on Human Colorectal Carcinoma cell line -HCT -116. The current study was envisioned to recognize the components present in the seed oil of Anethum sowa L. examined by GC-MS. Cyclohexanone,2-methyl-5-(1-methylethenyl)-, trans-(41.66%),cyclodecene,1-methyl-(28.15%),(1R,2R)-1,2-bis(prop-1-en-2-yl)cyclobutene(9.80%),(5S)-6,6-Dimethyl-2-azaspiro[4.4]nona-1-ene (1.05%), Benzene, 1-methoxy-4-methyl-2-[[[2-(4-nitrophenyl)hydrazine}carbonyl]amino]-(0.74%),L-Limonene(0.26%) were the new compounds found and reported.2,2-diphenyl-1-picryl-hydrazyl-hydrate test of extract exhibited a half-maximal inhibitory concentration of 640.129 μg/ml. The essential oil of seed showed effective antimicrobial activity against Klebsiella pneumoniae strain (MTCC 3384) &amp; Streptococcus mutants’ strain (MTCC 497) with a MIC of 20% and 10% respectively. Anticancer potential against HCT 116 exhibited that the seed oil and seed methanolic extract suppressed the cell progress in a concentration hooked on method, where seed oil with an IC50 99.38μg/ml was more active when compared with the extract. Seed oil also exhibited potent ant collagenase activity of 56.027% whereas extract showed only 34.312%. In silico docking was performed with the selected compounds of high concentration present in the seed oil with Adenomatous Polyposis Coli of Homo sapiens and MAI-150 peptidomimetic inhibitor as control. D-Limonene showed the maximum binding affinity with APC compared to the rest of the other compounds present in the Seed oil, which in turn confers the anticancer us property for the Seed oil. Keywords: Anticancer, Antimicrobial, Antioxidant, Anticollagense, Colorectal cancer, D-Limonene.

Optimization of Extraction Conditions and Characterization of Volatile Organic Compounds of Eugenia klotzschiana O. Berg Fruit Pulp.

Eugenia klotzschiana O. Berg is a native species to the Cerrado biome with significant nutritional value. However, its volatile organic compounds (VOCs) chemical profile is not reported in the scientific literature. VOCs are low molecular weight chemical compounds capable of conferring aroma to fruit, constituting quality markers, and participating in the maintenance and preservation of fruit species. This work studied and determined the best conditions for extraction and analysis of VOCs from the pulp of Eugenia klotzschiana O. Berg fruit and identified and characterized its aroma. Headspace solid-phase microextraction (HS-SPME) was employed using different fiber sorbents: DVB/CAR/PDMS, PDMS/DVB, and PA. Gas chromatography and mass spectrometry (GC-MS) were employed to separate, detect, and identify VOCs. Variables of time and temperature of extraction and sample weight distinctly influenced the extraction of volatiles for each fiber. PDMS/DVB was the most efficient, followed by PA and CAR/PDMS/DVB. Thirty-eight compounds that comprise the aroma were identified among sesquiterpenes (56.4%) and monoterpenes (30.8%), such as α-fenchene, guaiol, globulol, α-muurolene, γ-himachalene, α-pinene, γ-elemene, and patchoulene.

Lavandula viridis L´Hér. Essential Oil Inhibits the Inflammatory Response in Macrophages Through Blockade of NF-KB Signaling Cascade.

Lavandula viridis L´Hér. is an endemic Iberian species with a high essential oil yield and a pleasant lemon scent. Despite these interesting features, this species remains unrecognized and poorly explored by the food and pharmaceutical industries. Nevertheless, it has been valued in traditional medicine being used against flu, circulatory problems and to relieve headaches. Since these disorders trigger inflammatory responses, it is relevant to determine the anti-inflammatory potential of L. viridis L´Hér. essential oil in an attempt to validate its traditional use and concomitantly to increment its industrial exploitation. Therefore, in the present study the chemical composition of this volatile extract as well as the effect on ROS production, inflammatory response and proteasome activity on LPS-stimulated macrophages were disclosed. Also, its safety profile on keratinocytes, hepatocytes and alveolar epithelial cells was depicted, envisioning a future human administration. The essential oil was characterized by high quantities of 1,8-cineole, camphor and α-pinene. From a pharmacological point of view, the essential oil showed a potent antioxidant effect and inhibited nitric oxide production through down-modulation of nuclear factor kappa B-dependent Nos2 transcription and consequently iNOS protein expression as well as a decrease in proteasomal activity. The anti-inflammatory activity was also evidenced by a strong inhibition of LPS-induced Il1b and Il6 transcriptions and downregulation of COX-2 levels. Overall, bioactive safe concentrations of L. viridis L´Hér. essential oil were disclosed, thus corroborating the traditional usage of this species and paving the way for the development of plant-based therapies.

Blackberry phenolic and volatile extracts inhibit cytokine secretion in LPS-inflamed RAW264.7 cells

The anti-inflammatory activity of blackberries has been attributed to phenolic compounds, especially anthocyanins. The present study hypothesized that volatiles could contribute to anti-inflammatory activity as well. The anti-inflammatory properties of three blackberry genotypes varying in total volatile and phenolic contents were assessed by measuring concentrations of nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor -α (TNF-α) within LPS-inflamed RAW264.7 murine macrophage cells after a preventive treatment of either a phenolic or a volatile extract. Extracts from blackberry genotypes A2528T, A2587T and Natchez had total phenolic contents of 4315, 3369 and 3680 µg/mL, respectively, and total volatile contents of 283, 852 and 444 ng/mL, respectively. Phenolic and volatile extracts of all genotypes significantly lowered the secretion of NO, IL-6 and TNF-α in ranges varying between 20-42%, 34-60% and 28-73% inhibition, respectively. Volatile extracts exhibited greater anti-inflammatory properties than phenolic extracts, despite being present at much lower concentrations in the berries. Further research is needed to assess bioavailability and anti-inflammatory effect of blackberry volatiles in vivo.

Phytochemical Profile and Anticancer Potential of Endophytic Microorganisms from Liverwort Species, Marchantia polymorpha L.

Liverwort endophytes could be a source of new biologically active substances, especially when these spore-forming plants are known to produce compounds that are not found in other living organisms. Despite the significant development of plant endophytes research, there are only a few studies describing liverwort endophytic microorganisms and their metabolites. In the presented study, the analysis of the volatile compounds obtained from thallose liverwort species, Marchantia polymorpha L., and its endophytes was carried out. For this purpose, non-polar extracts of plant material and symbiotic microorganisms were obtained. The extracts were analyzed using gas chromatography coupled to mass spectrometry. Compounds with the structure of diketopiperazine in the endophyte extract were identified. Liverwort volatile extract was a rich source of cuparane-, chamigrane-, acorane-, and thujopsane-type sesquiterpenoids. The cytotoxicity of ethyl acetate extracts from endophytic microorganisms was evaluated on a panel of cancer (FaDu, HeLa, and SCC-25) cell lines and normal (VERO), and revealed significant anticancer potential towards hypopharyngeal squamous cell carcinoma and cervical adenocarcinoma.

Retama sphaerocarpa, Atractylis serratuloides and Eruca sativa honeys from Algeria: Pollen dominance and volatile profiling (HS-SPME/GC–MS)

The volatile fraction of three monofloral honey types produced in arid and semiarid areas of Algeria was studied to establish a link between their chemical composition and their botanical origin. Palynological analysis was performed to confirm the main botanical origin. Volatile extraction using HS-SPME coupled to GC–MS revealed exclusive components for each type: 1,6,10-dodecatrien-3-ol,3,7,11-trimethyl-, (E); 1,6-octadien-3-ol,3,7- dimethyl; phenol, 2-methoxy and 2-naphtalene methanol, decahydro-α,α,4a- trimethyl-8-methylene-, [2R-(2α,4aα,8a,8aβ)] for Atractylis honey, lilac aldehyde and lilac aldehyde D for Retama honey, and dimethyl trisulfide for Eruca. The PCA analysis made it possible to correlate some volatile compounds with the most important pollen types, and to evaluate the authenticity related to the geographical and botanical origin of the honey.

Sub-ambient temperature sampling of fish volatiles using vacuum-assisted headspace solid phase microextraction: Theoretical considerations and proof of concept

The extraction of volatiles from perishable food at a sub-ambient temperature using headspace solid-phase microextraction (HS-SPME) has not been considered in the past due to the corresponding loss in sensitivity. We propose HS-SPME sampling under vacuum (Vac–HS–SPME) to compensate problems of sensitivity loss and achieve substantial improvement in extraction efficiencies whilst sampling at temperatures as low as 5 °C. The approach was applied to fish samples, representing a highly vulnerable perishable food sample. The theoretical considerations explaining the performance of Vac–HS–SPME at sub-ambient temperatures are discussed and related to the increase in gas diffusivities when sampling under vacuum. A comparative study between Vac- and regular HS-SPME for the extraction of 18 compounds from salmon was carried out at different temperatures (5, 30 and 40 °C) and sampling times (10–60 min). For the majority of the compounds, Vac–HS–SPME at 5 °C yielded similar or superior extraction efficiencies than regular HS-SPME even when sampling at 40 °C. However, four compounds were better extracted at 1 atm presumably due to the intensification of competitive adsorption of analytes on the SPME fiber under vacuum or the partial losses of more volatile analytes during air-evacuation in the presence of the frozen samples. Sub-ambient temperature sampling (5 °C) combined with Vac–HS–SPME was also applied to monitor the changes in the 18 compounds present in salmon, redfish, and cod refrigerated for up to five days. The results were compared to those obtained with regular HS-SPME at 40 °C. Overall, Vac–HS–SPME sampling at 5 °C represents a new and powerful approach for the analysis of volatiles in refrigerated foods, and has a great potential for future studies in quality control and freshness assessment.

The Destruction of the Anaerobic Environment Caused by Rumen Fistula Surgery Leads to Differences in the Rumen Microbial Diversity and Function of Sheep.

This experiment was to study the impact of rumen fistula surgery on the rumen microbios in sheep. Six male adult Hu sheep (48.8 ± 0.23 kg, 0.5 years) were fed at 0700 and 1,800 with ad libitum access to water. The rumen fistula was installed in the same batch from 0600 to 0900. Monitoring the dry mater intake and the output of dry mater faces 1, 2, 4, 6, 8, 10, 12, 14 days after fistulated surgery. The collection of rumen fluid was arranged at 1d during rumen surgery (DRS1), 3d after rumen surgery (ARS3), and 14d after rumen surgery (ARS14) for volatile fatty acid (VFA) and DNA extraction for sequencing and bioinformatics analysis. There was no difference in DMI, the pH apparent digestibility of dry matter, organic matter, neutral detergent fiber, acid detergent fiber both before and 14 days after surgery. Increases were observed in the acetate and total VFA at ARS3. There was no difference in digestion of dry material, organic material, neutral detergent fiber, and acid detergent fiber before and after surgery. The relative abundance of Bacteroides decreased from 61.96% at DRS1 to 28.85% at ARS3. In comparison with the DRS1 and ARS3, the relative abundance of Firmicutes in the ARS14 increased to 44.58% (P < 0.01). Proteobacteria increased from 11.33% at DRS1 to 51.66% at ARS3 and then decreased to 11.39% at ARS14. Prevotella decreased form 61.06% at DRS1 to 28.04% in the ARS3. Succinivibrio increased from 8.32% at DRS1 to 48.58% at ARS3, but decreased to 10.43% in the ARS14. Compared with DRS1 and ARS3, the ARS14 was higher in the Simpson and Shannon index. As for the BugBase function prediction, rumen fistula surgery increased the microorganism abundance of aerobic and facultative anaerobic phenotype, and anaerobic phenotype was decreased in the ARS3. There was higher microorganism abundance of aerobic phenotype in the ARS14 than before fistula installation. In conclusion, the rumen fistula surgery destroys the anaerobic environment of rumen, leading to differences in rumen microbial diversity and function, but the apparent digestibility and total VFA were not affected.