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Copyright of Nonferrous Metals (Extractive Metallurgy) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this research is to create a distinctive chromatogram for the essential oil of Mosla chinensis Maxim., aiming to offer technical assistance for its quality management. Using gas chromatography (GC), according to the optimized chromatographic conditions, the GC method was used to analyze 15 batches of Mosla chinensis Maxim. essential oil samples. The results showed that a GC characteristic chromatogram for Mosla chinensis Maxim. essential oil from different regions was established, marking eight common peaks. The identified components included benzaldehyde, β-myrcene, pinene, γ-terpinene, o-cymene, (-)-terpinen-4-ol, thymol, and carvacrol, with thymol as the characteristic peak. The relative retention times of the eight distinct peaks were recorded as 0.308, 0.349, 0.388, 0.403, 0.469, 0.768, 1.000, and 1.012, in that order. The established chromatogram characteristic of the essential oil from Mosla chinensis Maxim. is notably unique. Furthermore, this essential oil exhibits excellent precision, stability, and reproducibility. [ABSTRACT FROM AUTHOR]

A method using high performance liquid chromatography (HPLC) was developed for the simultaneous determination of 13 preservatives (levulinic acid, p--hydroxyacetophenone, raspberry ketone, p--anisic acid, caprylhydroxamic acid, hydroxyethoxyphenyl butanone, methylisothiazolinone, phenoxyethanol, benzoic acid, methylparaben, chlorphenesin, dehydroacetic acid, and 5-bromo-5-nitro-1,3-dioxane) in cosmetics. Different types of samples were ultrasonically extracted by methanol, then the separation of 13 preservatives was carried out on a column of Agilent ZORBAX Eclipse XDB-C18 (250 mm × 4.6 mm, 5 μm) by gradient elution at a flow rate of 1.0 mL/min, using 0.1% phosphoric acid solution and acetonitrile as mobile phases. The column temperature was 30 °C, and the detection was completed by a diode array detector with the wavelengths at 275, 230 and 210 nm. Suspected positive samples were further confirmed by liquid chromatography--tandem mass spectrometry or gas chromatography--mass spectrometry. The linear regression analysis data shows good linearity for 13 preservatives in the respective mass concentration range, with their correlation coefficients (r) greater than 0.999 8. The limits of detection (LODs) and limits of quantitation (LOQs) of the method are in the ranges of 0.4-100.0 mg/kg and 1.2-250.0 mg/kg, respectively. At three spiked levels, the average recoveries for 13 target compounds in three kinds of matrix samples are within 84.0%-115.4%, and the relative standard deviations (RSD) are within 0.5%-4.8% (n = 6) . This method is convenient, efficient, and precise, which can be used for qualitative and quantitative analysis of common preservatives in daily cosmetics. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flavor is an important indicator of the edible quality of fresh corn. In order to explore the composition and content differences of volatile flavor compounds in different types of fresh corn, in this study, 6 different types of fresh corn varieties including NKN 323 were used as materials, and electronic nose technology and gas chromatography ion mobility spectrometry (GC-IMS) technology were used to detect the volatile flavor compounds in fresh corn to evaluate the contribution of volatile flavor compounds to the overall flavor of fresh corn by relative odor activity value (ROAV) . The results showed that a total of 34 volatile flavor compounds were identified, including 10 esters (34.68%~26.74%), 8 aldehydes (28.46%~21.22%), 6 alcohols (10.33%~6.04%), 5 ketones (14.74%~9.87%), 2 ethers (10.05%~6.94%) and 3 other compounds. GC-IMS fingerprints showed that the difference of volatile flavor compounds content important which caused the difference of characteristic flavor of different types of fresh corn. 5 common key aroma components and 23 different characteristic flavor compounds of fresh corn were identified by ROAV. The total release of volatile flavor compounds of different types of varieties was NKN323, followed by JKT608. Isovaleraldehyde contributed the most to the overall flavor of NKN336, JZN219, JKN768 and JKT608, while 3- octanone contributed the most to the overall flavor of NKN323 and JKN2000. Above results provided theoretical basis for the analysis and evaluation of volatile flavor compounds in fresh corn and the precise control of characteristic flavor. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Volatile components in red orange essential oil extracted by two cold pressing processes (cup pressing and lime method) were analyzed by gas chromatography quadrupole time-of-flight mass spectrometry (GC-Q/TOF). A total of 93 components were identified, 89 and 84 compounds were identified for the two types of red orange essential oils, respectively. Among the 93 components, there were 29 terpenes, 20 alcohols, 20 aldehydes, 5 esters, 2 ketones, 12 hydrocarbons, and 5 other compounds. There were 80 compounds shared by the two essential oils. The total volatile component content of red orange essential oil by cup pressing method was significantly higher than that by lime method. The highest content of these compounds was terpenes which total content was over 80%. In addition, the compounds with higher content were D-limonene, γ-terpinene, β-myrcene, linalool and α-pinene. According to principal component analysis (PCA), there was a significant difference in the volatile components of the two types of red orange essential oils. The relative odor activity value (ROAV) method indicated that linalool was the most important aroma component of the two red orange essential oils. And the citrus aroma properties of red orange essential oil extracted by cup pressing method was significantly stronger than that extracted by lime method. Linalool, thymol, β-myrcene, D-limonene, citronellal, and γ- terpinene were confirmed to the key aroma components of the red orange essential oils. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Current Biotechnology (2095-2341) is the property of Chinese Academy of Agricultural Sciences, Institute of Biotechnology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this research, the differences in protein and fatty acid composition among camel, cow and goat milks were analyzed by gel electrophoresis (GE) and gas chromatography (GC). The GE results showed that there were differences in the proportion of proteins in camel milk from different regions, and the production process had a significant effect on both camel milk protein and milk fat globule membrane protein composition. There were significant differences in protein composition among camel, cow and goat milks, and camel milk did not contain β-lacglobulin or αs1-casein, while cow and goat milks did not contain immunoglobulin G2 (IgG2) or IgG3. Therefore, GE could be used for the identification of camel milk mixed with cow or goat milk. The GC results showed that 31 fatty acids were detected in both camel and goat milks, and 29 fatty acids in cow milk. Camel milk contained fewer short-chain fatty acids than cow and goat milks, while the contents of most long-chain fatty acids were significantly higher than those in cow and goat milks. Principal component analysis (PCA) of the fatty acid composition data showed a clear separation of milks from different species and a clear discrimination between pure and adulterated camel milk. PCA can be used for the identification and analysis of fatty acids in camel milk mixed with cow milk and goat milk.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To establish an automated headspace -gas chromatography method for the determination of 1,1,2,2 - tetrachloroethene in human urine. Methods A urine sample of 5.00 mL was placed in a 20 mL headspace vial, and 2.0 g of anhydrous sodium sulfite was added before sealing the vial. The vial was placed in an automated headspace sampler and heated at 80 ℃ for 50.00 min to equilibrate. Under these heating conditions, 1,1,2,2 -tetrachloroethene in human urine was completely reacted with anhydrous sodium sulfite to form trichloroethylene. The trichloroethylene vapor above the headspace vial was separated by a DB-624 capillary column and detected with a flame ionization detector. Quantification was achieved by plotting a standard curve with the peak area of trichloroethylene and the mass concentration of 1,1,2,2- tetrachloroethane. Results The results showed good linear ranges of 1,1,2,2 -tetrachloroethene in urine between 0.008 3 and 32.000 mg/L, and the correlation coefficient was higher than 0.999 4. For this method, the limit of detection was 2.5 μg/L, and the lower limit of quantification was 8.3 μg/L; the intra-batch precision was 4.79% to 5.28%, and the interbatch precision was 4.61% to 6.44% ; the average recovery rate was 87.53% to 101.17% . Conclusions The automated headspace gas chromatography method for determining 1,1,2,2-tetrachloroethene in human urine was characterized by high sensitivity, good linearity, minimal interference, high precision, and simple sample preparation. It is suitable for measuring the concentration of 1,1,2,2-tetrachloroethene in human urine. [ABSTRACT FROM AUTHOR]

Chromatographic analysis represents a prevalent technique within modern instrumental analysis. Chromatography, encompassing both gas and liquid chromatographic methods, is a fundamental component of instrumental analysis experiment course in higher education institutions. Despite their shared separation principles, gas chromatography (GC) and liquid chromatography (LC) exhibit distinct characteristics and applications. Leveraging the comparative teaching method, this study involves the execution of chromatographic separation of benzene, toluene and m-xylene using both GC and LC instruments within the framework of an instrumental analysis experimental course. This comparative approach facilitates a deeper understanding and appreciation of chromatographic techniques among students by elucidating the theoretical underpinnings, experimental conditions, operational methodologies, and outcomes associated with each method. Furthermore, this pedagogical strategy serves as a preparatory step for students’ future research endeavors. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Science & Biotechnology is the property of Journal of Food Science & Biotechnology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Condiment is the property of China Condiment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objectives] The paper aimed to investigate the characteristic aroma components of black tea from the main production areas in Jiangsu Province and distinguish the key difference components in different main production areas. [Methods] The aroma composition of representative Jiangsu black tea samples from the main production areas was analyzed using electronic nose (E-nose) and headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) technology. [Results] The electronic nose analysis showed that terpenoids and aromatic ring substances were the main volatile components in the aroma of Jiangsu black tea, and the contents of alcohols, ketones, aldehydes, sulfur components and terpenoids were significantly higher in Yixing production area than those in Jurong and Jintan production areas. HS-SPME-GC-MS analysis showed that alcohols were the volatile compounds with the highest proportion in all Jiangsu black teas, accounting for 62.06%-75.66% of the total volatile. With relative odor activity value (ROAV) greater than 1.00 as the criterion, a total of 12 key aroma presenting substances were screened out, and linalool, geraniol, citral, trans-ẞ-ionone, decanal, dimethyl sulfide might be the most critical aroma components in Jiangsu black tea (ROAV>10.00). Orthogonal partial least squares discriminant analysis (OPLS-DA) showed that there were some differences between the aroma components of black tea from different production areas. Seven variance components were screened using variable importance in projection (VIP) values greater than 1.00 as a criterion. Among them, 2-methyl-butanal and phenylacetaldehyde in fruity aroma and trans-linalool oxide (furans) in woody aroma were the key aroma components that distinguished the Jintan production area from Yixing and Jurong production areas, and cis-jasmone in floral aroma was the key aroma component that distinguished the Jurong production area from the Jintan and Yixing production areas, which were the key factor causing the aroma difference among production areas. In addition, the ratio of geraniol to linalool content in the main production areas of Jiangsu black tea was about 1:1, which was presumed to be one of the important reasons for the difference between Jiangsu black tea and other famous black teas. [Conclusions] In this study, the characteristic aroma components of Jiangsu black tea were clarified by combining HS-SPME-GC-MS and electronic nose technology, and the different aroma components of Jiangsu black tea from different production areas were explored, and the results laid a foundation for enriching the aroma theory of black tea in China. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To explore the effect of yeast-Agastache rugosus complex solution on the deodorization of tilapia, the deodorization process was optimized by single factor and response surface experiments. Gas chromatography ion mobility spectroscopy (GC-IMS) was used to identify the volatile components of tilapia meat before and after deodorization, and partial least squares discriminant analysis (OPLS-DA) was used to distinguish and analyze the differences. Results showed that when the conditions of a mass concentration of 2.1 g/100 mL, the ratio of solid to liquid was 1:3.09 (g:mL), and the deodorization time of 32 minutes, the fishy degree was the lowest and the sensory score was the highest. A total of 22 volatile compounds, mainly aldehydes and alcohols, were detected by GC-IMS. After deodorization, the relative content of aldehydes decreased from 50.64% to 40.82%, and that of alcohols decreased from 34.00% to 27.77% . According to the odor threshold value, the substances with relative odor activity value (ROAV) was greater than 1 were 1-octen-3-ol, 1-hexanol, heptanal, nonanal, octyl aldehede, ethyl acetate, and acetic acid hexyl ester. Five key fishy substances (VIP > 1) were screened by partial least squares discriminant analysis and variable importance in projection (VIP). They were octyl aldehede, nonanal, heptanal, 1-octen-3- ol, and 1-hexanol. The interaction of these substances had an important impact on the fishy smell of tilapia. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to improve the yield and quality of tiger nut oil, the strategy of ultrasonic-assisted n-hexane was studied by response surface methodology. In this study, the total phenolic content, total flavonoid content, free radical scavenging rate, fatty acid composition, and 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) clearance rate in oil samples were investigated at three temperatures including 25 ℃ (room temperature), 47 ℃ (optimal temperature for ultrasound assisted extraction), and 60 ℃ (high temperature). The results showed that a high tiger nut oil extraction yield of 25.01%±0.03% was obtained at a solid-liquid ratio of 1:15 (g/mL), ultrasonic time of 20 min, ultrasonic temperature of 47 ℃, and particle size of 70 mesh. The obtained oil sample was yellow-orange and slightly turbid with a unique aroma of beans. Besides, tiger nut oil had a certain scavenging effect on DPPH free radicals. Ultrasound could better dissolve the nutrients in tiger nut, but it had a large destruction effect on tiger nut flavonoids, while the content of phenolic acids significantly (P

Methane (CH4) clumped isotope analysis plays a crucial role in the fields of climate change, energy exploration, and planetary research. The purity of CH4 in samples directly affects the precision and accuracy of high-resolution mass spectrometry in clumped isotope analysis. Addressing the challenge associated with enriching and purifying CH4 components in gas samples, this study optimized conditions such as carrier gas line speed and sample injection volume based on the principles of gas chromatography (GC) component separation, with real-time monitoring of component peak shapes. Additionally, the recovery rate was quantified using an external standard method and purity was verified through GC component analysis to ensure the effectiveness of the purification process. By optimizing the chromatography-vacuum low-temperature enrichment preparation method, the optimal carrier gas line speed for the IBEX system was determined to be 12 mL/min, with a CH4 injection volume less than 12 mL. This facilitated visualization of GC peak shapes, thus ensured that the CH4 peak was essentially separated from the adjacent N2 interference peak, achieving high-purity enrichment of the CH4 single component. When the CH4 content in gas samples was less than 70% and the air content was high, secondary purification was required to improve CH4 purity. The causes of CH4 isotopic fractionation during purification using adsorbents like 5Å molecular sieves were discussed, and extending the CH4 collection time was proposed to eliminate the interference from the 5Å molecular sieve. Currently, this method requires approximately 90 min for a single purification process, with CH4 recovery and purity ranging from 90.1% to 95.7% and 97.3% to 98.9%, respectively. The differences in isotopic composition (δ13CVPDB and δDVSMOW, Δ13CH3D, and Δ12CH2D2) are all less than the analytical error of the mass spectrometer, making them almost negligible.

BackgroundPropylene glycol monomethyl ether (PGME) is a widely used organic solvent. It exists in the form of two isomers in the workplace, which will cause adverse effects such as eye and upper respiratory tract irritation in workers. However, there is still a lack of standard detection methods for simultaneous detection of two isomers of PGME in China. ObjectiveTo establish a solvent desorption-gas chromatographic method for two isomers of PGME [1-methoxy-2-propanol (α-PGME), 2-methoxy-1-propanol (β-PGME)] in workplace air. MethodsA method of solvent desorption-gas chromatography for α-PGME and β-PGME in workplace air were proposed. Air samples were collected with solvent desorption activated carbon tubes, desorbed using a desorption solution of dichloromethane/methanol (85:15), and then separated on a free fatty acid phase (FFAP) fused silica capillary chromatography column , detected with a flame ionization detector (FID), and quantified by peak area. Standard evaluation protocol was followed to obtain key indicators: standard curve, limit of detection, lower limit of quantification, relative standard deviation (RSD) that measures precision, and spiked recovery of sample solutions that measures accuracy. Desorption efficiency, sampling efficiency, and adsorption capacity tests were conducted, sample stability was evaluated using spiked activated carbon tube preservation test, and interference test was also assessed. The developed method was then applied to field air sample testing. ResultsIn this method, using dichloromethane/methanol (85:15) as the sample desorption solution, the quantitative detection ranges of α-PGME and β-PGME were 0.95-923.0 μg·mL−1 and 0.97-912.0 μg·mL−1 with both correlation coefficients of 0.999 9, the method limits of detection were 0.28 µg·mL−1 and 0.29 µg·mL−1, and the lower limits of quantification were 0.95 µg·mL−1 and 0.97 µg·mL1, respectively. The lowest concentrations detected were both 0.19 mg·m−3, and the lowest concentrations quantified were 0.63 mg·m−3 and 0.65 mg·m−3, respectively, under the conditions of sampling volume of 1.5 L and the volume of desorption solution of 1.0 mL. The intra-batch precisions for α-PGME and β-PGME were 2.8%-4.9% and 2.8%-5.1%, the inter-batch precisions were 4.2%-5.7% and 4.5%-5.9%, the spiked recoveries were 98.8%-100.3% and 96.4%-102.9%, and the desorption efficiencies were 92.7%-97.3% and 92.2%-98.1%, respectively. The average sampling efficiency was 100%, and the samples could be stored at room temperature (25-30 ℃) for at least 7 d and at 4 ℃ for at least 15 d. The adsorption capacities of the activated carbon sampling tube for α-PGME and β-PGME were greater than 13.9 mg and 2.7 mg (100 mg of activated carbon adsorbent), respectively. Possible co-existing components in workplace did not interfere with the determination of α-PGME and β-PGME. The short-time exposure concentrations of α-PGME and β-PGME in the spray painting unit of an automobile manufacturing company were determined to be 18.69 mg·m−3 and 2.19 mg·m−3, and the time-weighted average concentrations were 6.03 mg·m−3 and 1.08 mg·m−3 respectively. ConclusionThis method is accurate, precise and suitable for on-site monitoring of the two isomers of PGME in workplace air.

In order to ensure the accuracy of laboratory test results, the uncertainty of the determination of indicative polychlorinated biphenyls in fish by gas chromatography was evaluated. According to the national Food Safety standard, National Food Safety Standard Maximum Levels of Contaminants in Foods (GB 2762-2022), the content of PCB28, PCB52, PCB101, PCB118, PCB138, PCB153 and PCB180) in the "measured" samples was determined as the total content of PCBs. Then, the polychlorinated biphenyls (PCBs) measurement model was re-established according to the "measured" and detection standard, and then the weight of uncertainty affected by the measurement model on test results were analyzed and evaluated. After evaluation, the measurement result of PCBs in quality control fish samples was 149.1 μg/kg, and the relative extended uncertainty was Ur=2.9%, k=2. The contribution of uncertainty was measurement repeatability 70.8%, sample weight 0.025%, internal standard volume 1.8%, sum of concentration ratios of each target in sample solution 27.3%.

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Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)