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•The aroma profile and odorant composition of Nile Tilapia from RAS were determined.•Fourteen odor compounds were found for the first time in Nile Tilapia from RAS.•Two different ...depuration approaches led to a reduced perception of several odorants.
Off-flavors are a major challenge for companies using recirculated aquaculture systems (RAS). In the presented work, we comprehensively characterize the odorant composition of Nile tilapia (Oreochromis niloticus) raised in RAS and compare the impact of two depuration processes on the odorant composition and aroma profile of the fish. Fish collected from the production tank and after two different tank pre-disinfection approaches in the depuration process (high pH versus H2O2) were investigated. A combined sensory-instrumental investigation revealed the presence of 115 odorants, of which 83 were successfully identified. The compounds decanal, tridecanal, (Z)-1,5-octadien-3-one, octane-2,3-dione, benzophenone, non-3-yn-1-ol, γ-dodecalactone, (Z)-geranylacetone, 2,3-diethyl-5-methylpyrazine, 1-methylpyrrolidin-2-one, 2-acetyl-2-thiazoline, benzothiazole, skatole, and 5α-androst-16-en-3-one were detected with the highest flavor dilution factors and are described for the first time as odor-active compounds in fish from RAS. The results indicate that depuration decreased the levels of 78 different odorants from the fish, including the potent earthy smelling odorants geosmin, isoborneol and 2,3-diethyl-5-methylpyrazine.
Background. Routine application of the GC-MS method to assess the URT microbiota can potentially improve the efficacy and safety of treatment for chronic respiratory diseases. Aim. To perform a ...comparative analysis of the microbiota from the surface of the pharyngeal tonsil, from the deep parts of the nose, and saliva in children with chronic adenoiditis. Materials and methods. The study included 90 patients with chronic adenoiditis (CA) and/or pharyngeal tonsil hypertrophy (PTH). All study participants had swabs taken from the surface of the pharyngeal tonsil, from the deep parts of the nasal cavity, and saliva as a biological fluid of the oral cavity. Microorganisms were identified by specific fatty acids using GC-MS to assess the composition of the microbial community on the surface of the pharyngeal tonsil. Results. The study showed that the microbiota of the nasopharynx is identical in its qualitative composition to microorganisms from the deep parts of the nose. However, according to the results of the analysis of microbial markers of saliva, the oral microbiota showed significant differences in the quantitative and qualitative composition of microorganisms compared with the nasopharyngeal microbiota. Conclusion. The introduction of the GC-MS method for assessing the URT microbiota enables its monitoring in clinical practice for the treatment of chronic respiratory system diseases without disturbing the ecology of the mucous membranes and the whole body.
Lavender oil is one of the most valuable aromatherapy oils, its anti-bacterial and anti-fungal activities can be explained by main components such as linalool, linalyl acetate, lavandulol, geraniol, ...or eucalyptol. The aim of the study was to assess the anti-microbial effects of two different lavender oils on a mixed microbiota from facial skin. The commercial lavender oil and essential lavender oil from the Crimean Peninsula, whose chemical composition and activity are yet to be published, were used. Both oils were analysed by gas chromatography coupled to mass spectrometry. The composition and properties of studied oils were significantly different. The commercial ETJA lavender oil contained 10% more linalool and linalyl acetate than the Crimean lavender oil. Both oils also had different effects on the mixed facial skin microbiota. The Gram-positive bacilli were more sensitive to ETJA lavender oil, and Gram-negative bacilli were more sensitive to Crimean lavender oil. However, neither of the tested oils inhibited the growth of Gram-positive cocci. The tested lavender oils decreased the cell number of the mixed microbiota from facial skin, but ETJA oil showed higher efficiency, probably because it contains higher concentrations of monoterpenoids and monoterpenes than Crimean lavender oil does.
•Fungal sterols of two Tuber species were thoroughly analyzed by GC/MS.•A sensitive GC/MS SIM method was introduced for minor sterol detection.•27 sterols with 27–31 carbon atoms were detected in the ...samples.•All but four sterols could be traced back to structures.•Sterol profiles could be traced back to fungal biosynthesis pathways.
Fungal sterols (mycosterols) were investigated in seven samples of both Tuber aestivum and Tuber borchii truffles from Italy, Spain and Romania by means of gas chromatography with mass spectrometry (GC/MS). Sterol contents varied from 130 to 590 mg/100 g dry weight (T. borchii) and 110−420 mg/100 g dry weight (T. aestivum). The sterol pattern of both truffle species was dominated by ergosterol (60–85 %) and brassicasterol (4–33 %). In addition, 25 minor sterols were detected with 27 (n = 3), 28 (n = 17), 29 (n = 3), 30 (n = 2) and 31 (n = 2) carbon atoms (Limit of detection: 2 μg/100 g dry weight). Fourteen minor sterols were described for the first time in Tuber species. Ten minor compounds were detected in all samples in varying abundances, while the others were (i) exclusively detected in all samples of one species (T. borchii: fecosterol, ergosta-8-enol; T. aestivum: 24-methyleneergosta-5,22,24-trienol) or (ii) varied strongly in abundance (≥90 %). Variations in main and selected minor sterols could be partly related to different harvest times. In addition, differences in fungisterol and ergosta-5,7-dienol between the both species were attributed to different pathways in fungal sterol biosynthesis (oneway ANOVA p ≤ 0.01). Our study indicates that sterol pattern analysis could be used to differentiate different Tuber species.
The increasing demand of valuable truffles (Tuber sp.) has prompted new areas of naturally growing truffles entering the market. Hence, the identification of valueless Tuber species is an important ...task to prevent food fraud. Here, we show that sterol patterns are suited to differentiate five Tuber species (Tuber magnatum, Tuber melanosporum, Tuber aestivum, Tuber albidum, and Tuber indicum varieties) from each other. Next to the known main sterols of Tuber, ergosterol and brassicasterol, occurrence of minor sterols in differing shares resulted in characteristic fingerprints in the five Tuber species, irrespective of the country of origin. A total of 27 sterols were evaluated, and we proposed assignment criteria of main sterol relations as well as eight distinct biomarkers within the minor compounds for the differentiation of European and Chinese truffles.
Sterols are known for a plethora of 250 different structures. Between 5 and 10% of them usually occur with varying abundance ratios (~ four orders of magnitude) and total amounts (0.4–1000 mg/100 g ...oil) in samples. Yet, quantitative data are mostly restricted to the few major sterols which are available as reference standards. Here, we developed a gas chromatography with mass spectrometry method operated in selected ion monitoring mode (GC/MS-SIM) that enabled the quantitation of 30 (silylated) sterols although only ten were available as reference standards. This could be obtained by studying the full-scan mass spectra of these ten sterol standards and 20 additional sterols measured in seven oils. In the next step, sterols were assigned to different groups. Values for quantification were then selected on the premise that response factors were constant within a sterol group. The deviation of the response factors within one sterol group was frequently below ± 10% and otherwise about ± 11–12%. Using mean response factors for all sterols, the novel GC/MS-SIM quantification method was superior to GC/FID which was exemplarily applied to two oils. Between eight and 21 of the 30 studied sterols and pentacyclic triterpenols were detected and quantified in 18 vegetable oils and two vegetable fats. The much higher number of sterols that could be quantified resulted in higher sterol amounts and the method and data may be useful for food authentication.
Sterols are a highly complex group of lipophilic compounds present in the unsaponifiable matter of virtually all living organisms. In this study, we developed a novel gas chromatography with mass ...spectrometry selected ion monitoring (GC/MS-SIM) method for the comprehensive analysis of sterols after saponification and silylation. A new referencing system was introduced by means of a series of saturated fatty acid pyrrolidides (FAPs) as internal standards. Linked with retention time locking (RTL), the resulting FAP retention indices (RI
FAP
) of the sterols could be determined with high precision. The GC/MS-SIM method was based on the parallel measurement of 17 SIM ions in four time windows. This set included eight molecular ions and seven diagnostic fragment ions of silylated sterols as well as two abundant ions of FAPs. Altogether, twenty molecular ions of C
27
- to C
31
-sterols with 0–3 double bonds were included in the final method. Screening of four common vegetable oils (sunflower oil, hemp oil, rapeseed oil, and corn oil) enabled the detection of 30 different sterols and triterpenes most of which could be identified.
Graphical abstract
Pesticides, widely applied in agriculture, can produce a variety of transformation products and their continuous use causes deleterious effects to ecosystem. Efficient and sensitive analytical ...techniques for enrichment and analysis of pesticides samples are highly required. Compared with other extraction methods, solid‐phase micro extraction is a solvent free, cost effective, robust, versatile, and high throughput sample preparation technique, especially for the analysis of pesticides from complicated matrices. Coupling of solid‐phase micro extraction with gas chromatography and mass spectrometry and liquid chromatography–mass spectrometry has been extensively applied in pesticide analysis. On the other hand, in recent years, combination of fast separation using solid‐phase micro extraction and rapid detection using ambient mass spectrometry is providing highly efficient pesticide screening. This article summarizes the applications of solid‐phase micro extraction coupled to mass spectrometry for pesticides analysis.
A novel microwave‐assisted‐demulsification dispersive liquid–liquid microextraction technique was established for determination of three triazole fungicides in environmental water samples by gas ...chromatography with mass spectrometry. Importantly, microwave irradiation has been applied in demulsification to achieve the phase separation and enrichment of triazole fungicides in water samples successfully with low‐density toluene as extractant. The experimental variables, including microwave power, microwave time, ultrasonic time, type and volume of extraction solvent, and effect of salting out were investigated. Under the optimized conditions, the method showed good linearity for myclobutanil, tebuconazole, and difenoconazole in the range of 1–100 μg/L. The limits of detection and the limits of quantification were within the range of 0.14–0.27 and 0.47–0.90 μg/L, respectively. The suitable enrichment factors for three triazole pesticides were in the range of 425–636. The recoveries were between 89.3 and 108.7%, and the relative standard deviations were from 5.4 to 8.6%. Finally, environmental water samples were used to verify the applicability of the proposed method for analysis of triazole fungicides targets. It can be concluded that the developed microwave‐assisted‐demulsification dispersive liquid–liquid microextraction gas chromatography with mass spectrometry method was a rapid, efficient, reliable, and environmental friendly way for analysis of triazole fungicides in water.
A new, fast, simple, and environmentally friendly analytical method has been developed to determine six siloxanes in water samples: octamethyltrisiloxane, octamethylcyclotetrasiloxane, ...decamethyltetrasiloxane, decamethylcyclopentasiloxane, dodecamethylpentasiloxane and dodecamethylcyclohexasiloxane. The analytical method consists of magnetic solid‐phase extraction employing graphene oxide/Fe3O4 as sorbent for the separation and preconcentration of siloxanes prior to GC–MS determination. The extraction procedure was optimized by means of a Plackett‐Burman design. Under the optimized extraction conditions (graphene oxide/Fe3O4, 20 mg; extraction time, 10 min; eluent volume, 0.5 mL ACN; elution time, 2.5 min; sample volume, 20 mL), the method rendered repeatability levels with a relative standard deviation between 9 and 20% (n = 6, 10 μg/L). Methodological limits of detection ranged from 0.003 to 0.1 μg/L. The linearity of the method was studied between the methodological limit of quantification and 100 μg/L, obtaining correlation coefficient values between 0.990 and 0.999. The applicability of the method was assessed by analyzing drinking, river and wastewater samples. Relative recovery values ranged between 70 and 120% (1 and 60 μg/L spiking level) showing that the matrix had a negligible effect on extraction. Finally, the greenness of this method was confirmed by the semiquantitative Eco‐Scale metrics.
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