Coastal wetlands function as critical retention zones for environmental microplastics, potentially accelerating their degradation through unique hydrological conditions. This study conducted a comprehensive 24-month in situ experiment at the Chongming Dongtan National Nature Reserve, examining the weathering processes of five morphologically distinct polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics. Quarterly analyses revealed progressive surface deterioration in all microplastics after initial exposure, followed by polymer-specific fragmentation patterns and environmental pollutant adherence. Surface elemental analysis showed rising O/C ratios, with intertidal zones exhibiting higher variance (0.0014-0.0096 vs 0.0006-0.0028 supratidal). Carbonyl index (CI) displayed fluctuating increases, with PS showing the highest CI rise (75.75%/year intertidal vs 61.77%/year supratidal). Systematic comparisons identified three weathering determinants: enhanced intertidal degradation from mechanical-photochemical synergy; spherical particles degrading faster than films via larger surface area; and polymer vulnerabilities dictating PS > PP > PE degradation rates. These findings demonstrate that microplastic weathering in coastal wetlands is collectively governed by hydrological conditions, particle morphology, and polymer composition, providing crucial quantitative parameters for assessing environmental persistence and ecological risks in these sensitive transition ecosystems.

The authenticity of fish products has become a widespread issue in markets due to substitution and false labeling. Lipidomics combined with chemometrics enables the fraudulence identification of food through the analysis of a large amount of data. This study utilized ultra-high-performance liquid chromatography (UHPLC)-QE Orbitrap MS technology to comprehensively analyze the lipidomics of commercially available basa catfish and sole fish. In positive and negative ion modes, a total of 779 lipid molecules from 21 lipid subclasses were detected, with phospholipid molecules being the most abundant, followed by glycerides molecules. Significant differences in the lipidome fingerprinting between the two fish species were observed. A total of 165 lipid molecules were screened out as discriminative features to distinguish between basa catfish and sole fish, such as TAG(16:0/16:0/18:1), PC(14:0/22:3), and TAG(16:1/18:1/18:1), etc. This study could provide valuable insights into authenticating aquatic products through comprehensive lipidomics analysis, contributing to quality control and consumer protection in the food industry.

Larimichthys crocea (LYC) holds significant economic value as a marine fish species. However, inaccuracies in labeling its origin can adversely affect consumer interests. Herein, a laser assisted rapid evaporative ionization mass spectrometry (LA-REIMS) and machine learning (ML) was developed for geographical authentication. When compared to iKnife, the LA demonstrated to be superior owing to reduced thermal damage to sample tissue, enhanced automation, and ease of use. Analysis of LYC from six distinct geographical origins across China revealed a total of 798 ions, which were then subjected to six classifiers to establish ML models. Following hyperparameter optimization and feature engineering, the Chi2(15%)-KNN model exhibited the highest training and testing accuracy, achieving 98.4 +/- 0.9% and 98.5 +/- 1.4%, respectively. This LA-REIMS/ML methodology offers a rapid, accurate, and intelligent solution for tracing the origin of LYC, thereby providing valuable technical support for the establishment of traceability systems in the aquatic product industry.

Freezing is one of the most commonly used preservation methods for Bluefin tuna (Thunnus orientalis). However, repeated freezing and thawing would inevitably occur due to the temperature fluctuation, leading to the microstructure damage, lipid oxidation and protein integrity decline of tuna muscle without notable visual appearance change. In this study, we used a rapid evaporative ionization mass spectrometry (REIMS) technique for the real-time determination of the extent of repeated freezing and thawing cycles in tuna fillets. We found significant variance in the relative abundance of fatty acids between bluefin tuna and its fresh counterpart following freeze-thaw cycles. Meanwhile, the difference is statistically significant (p < 0.05). The quality of tuna remains largely unaffected by a single freeze-thaw cycle but significantly deteriorates after freeze-thaw cycles (freeze-thaw count ≥2), and the relative fatty acid content of the ionized aerosol analysis in the REIMS system positively correlated with the number of freeze-thaw cycles. Notably, palmitic acid (C 16:0, m/z 255.23), oleic acid (C 18:1, m/z 281.24), and docosahexaenoic acid (C 22:6, m/z 327.23) displayed the most pronounced changes within the spectrum of fatty acid groups.

A liquid chromatography-tandem mass spectrometry (LC-MS) method for screening 53 stimulants in animal foods was developed. The method uses 2% formic acid-acetonitrile/water (80/20) as the extraction solvent and carries out one-step purification by FaVEx-AP solid phase extraction column. Endeavorsil C18 column was used for separation, and multiple reaction monitoring (MRM) mode was used for data acquisition and analysis. The results showed that the correlation coefficient (R2) was more than 0.99. The detection limit and quantification limit were 0.25–10μg/kg and 1–10μg/kg. The recoveries were 62.25%–123.32% and the relative standard deviation (RSD) was 1.17%–22.03%. The method is rapid, simple and accurate, and is suitable for the determination of 53 kinds of stimulants in animal-derived foods.

建立高效的海洋沉积物样品前处理方法及高灵敏度的气相色谱(GC)—串联质谱(MS/MS)条件精准测定海洋沉积物中 9 种咔唑(CZ)及卤代咔唑(PHCZs).冷冻干燥后的海洋沉积物样品经加速溶剂萃取仪提取,使用凝胶渗透色谱法净化并氮吹至近干,用丙酮复溶后采用GC—MS/MS进行检测,外标法定量.结果表明:9 种目标物在 0.10～10.00 μg/kg 或 0.20～10.00 μg/kg内线性关系良好,相关系数大于 0.996,该方法定量限为 0.10～0.20 μg/kg.在 1 倍、3 倍、10 倍定量限的加标水平下,9 种 CZ 及PHCZs的回收率为 83.5％～115.0％,相对标准偏差为 3.43％～9.77％.该方法具有操作步骤简单、自动化程度高、灵敏度高、定性定量准确的优点,满足海洋沉积物中 9 种CZ及PHCZs的检测需求.

Microplastics (MPs) have become an important global issue in recent years. However, MPs in the soil have received far less attention than water. Effective and nondestructive extraction of MPs is important for studying MPs in agricultural soils. This study uses different floatation solutions as experiments and uses MgCl2 as the floatation solution of the density extraction method. Five types of standard MPs (PE, PP, PS, PVC, and PET) are used as the objects of this experiment. The recovery of the two particle sizes was between 90.82% and 109.69%. The extracted standard MPs were then subjected to IR and Raman spectroscopic analysis, and the results showed that Raman spectroscopy was more suitable for the identification of the extracted MPs. Finally, this method collected and verified a vast number of soil samples and further analyzed the abundance and characteristics of the collected MPs.

该研究旨在建立散装即食食品中沙门氏菌、金黄色葡萄球菌和蜡样芽孢杆菌3种食源性致病菌的多重荧光定量PCR检测方法,根据沙门氏菌侵染上皮细胞表面蛋白的invA基因、金黄色葡萄球菌的耐热核酸酶(nuc)基因、蜡样芽孢杆菌的cerA基因分别设计3对特异性引物与探针,并对体系中引物探针的浓度以及退火温度等反应条件进行优化筛选,建立多重荧光定量PCR检测方法,同时评估其特异性、灵敏性及重复性,并应用该方法检测散装即食食品样本中致病菌,同时与国标法比对.结果表明,建立的多重荧光定量PCR检测方法能特异性地扩增沙门氏菌、金黄色葡萄球菌和蜡样芽孢杆菌3种目标菌,其他菌株均不扩增,灵敏度分别为4×102、3×102、2×102cfu/mL,且批内和批间变异系数均小于2％,重复性和稳定性良好.同时用国标法和多重荧光定量PCR法对100份散装即食食品样本进行检测比对,多重荧光定量PCR法的阳性检出率略高于传统国标法,且检测时间大幅缩短.综上所述,建立的多重荧光定量PCR检测方法特异性强、灵敏度高、快速准确,在食源性致病菌快速筛查方面具有良好的应用前景.

Lipase-catalyzed transesterification of structured phospholipids (sPLs) is a hot topic, but the structural variation of the fatty acyl chains in intact phospholipids at the molecular level remains unclear to date. The present study explored the detailed characteristics of synthesized phospholipids through high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in precursor ion scan mode. The optimal conditions were in-depth inspected and determined for the reaction system, including phospholipase A1 as catalyst, 15% lipase loading, and 1% water content. The sPLs enriched with EPA/DHA were structurally and quantitatively characterized by focusing on the fragments of m/z 301.6 (eicosapentaenoic acid, EPA) and m/z 327.6 (docosahexaenoic acid, DHA), and the results were statistically analyzed using partial least squares discriminant analysis and clustered heatmap hierarchical clustering analysis. PC 38:6 (18:1/20:5), PC 38:7 (18:2/20:5), PC o-40:6 (o-18:0/ 22:6), and PE 40:8 (18:2/22:6) etc. were revealed as the main variables that were active in the reaction.

The fish fillets of basa catfish (Pangasius bocourti) and sole fish (Cynoglossus semilaevis Gunther) have similar appearance but different market values, leading to the possibility of adulteration for economic gains. In this study, a surgical knife, namely iKnife, was coupled to rapid evaporative ionization mass spectrometry (REIMS) to develop a high-throughput technique for in situ and real-time authenticating these two fish species. The iKnife generated informative aerosol, which was further aspired into mass spectrometry to acquire specific fingerprinting profiles. The spectra were multivariate statistical analyzed, and the most contributing ions responsible for the significant difference between the lipidomics profiles of basa catfish and sole fish were screened out. For instance, ions of m/z 281.2470, 279.2319, 699.4970, etc. were abundance in basa catfish, while m/z 301.2164, 327.2341, 764.5284, etc. were significant in sole fish. Subsequently, the validation of the method was carried out in terms of intra-day precision (RSD 5.06%–8.65%) and inter-day precision (RSD ≤9.17%). Finally, this established iKnife-REIMS method was successfully applied to blind samples from markets with an accuracy greater than 98%. The results indicated that the proposed iKnife REIMS method could be used to unambiguously authenticate these two easily adulterated basa catfish and sole fish, and provide the basis and potential for the high-throughput identification of marine resources on the market.

Lipase-catalyzed transesterification of structured phospholipids (sPLs) is a hot topic, but the structural variation of the fatty acyl chains in intact phospholipids at the molecular level remains unclear to date. The present study explored the detailed characteristics of synthesized phospholipids through high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in precursor ion scan mode. The optimal conditions were in-depth inspected and determined for the reaction system, including phospholipase A1 as catalyst, 15% lipase loading, and 1% water content. The sPLs enriched with EPA/DHA were structurally and quantitatively characterized by focusing on the fragments of m/z 301.6 (eicosapentaenoic acid, EPA) and m/z 327.6 (docosahexaenoic acid, DHA), and the results were statistically analyzed using partial least squares discriminant analysis and clustered heatmap hierarchical clustering analysis. PC 38:6 (18:1/20:5), PC 38:7 (18:2/20:5), PC o-40:6 (o-18:0/22:6), and PE 40:8 (18:2/22:6) etc. were revealed as the main variables that were active in the reaction.

Lipids are closely related to biological mechanisms with their critical role in membrane structures, energy storage, and signaling. Therefore, lipidomics studies have become an essential tool in a biological system applied in new drug research and the discovery of disease-related metabolic markers. Nevertheless, the physicochemical and structural diversity of lipids poses a great challenge to lipidomics research. With modern technology development, hydrophilic interaction chromatography coupled to mass spectrometry has proven to be an excellent tool to separate and identify lipids according to their fatty acyl chains and various classes. The analysis of long-chain polyunsaturated fatty acids (PUFAs) in fish oil has been a hot topic in marine biology research. Moreover, n-3 PUFA bound to phospholipids possess higher bioavailability and bioactivity as reported, which can prevent and alleviate some diseases. In this chapter, we mainly introduce the HPLC-MS method utilized in PLs research of fish samples and how to profile phospholipids from different molecular classes.

With the rapid increase in the use of plastic films, microplastic (MP) pollution in agricultural soils has become a global environmental problem. Propiconazole is widely used in agriculture and horticulture; however, its role in plastic film degradation remains elusive. Butylene adipate-co-terephthalate (PBAT) and polyethylene (PE) films were used to analyze the effects of propiconazole on plastic film and MP degradation. We identified the surface morphologies of PBAT and PE at different propiconazole concentrations and soil pH values, as well as the adsorption and release characteristics of heavy metals during the degradation process via scanning electron microscopy, Fourier transform infrared spectroscopy and inductively coupled plasma mass spectrometry. Propiconazole accelerated the degradation of MPs, adsorption of heavy metals (Ni and Zn), and release of Sn at low concentrations (≤40 mg/kg); however, these effects were evidently absent at a high concentration (120 mg/kg). Furthermore, MPs were more prone to degradation in acidic or alkaline soils than in neutral soil when they coexisted with propiconazole. Hence, we suggest that PBAT and PE plastic films may not be suitable for application in acidic and alkaline soils with propiconazole, because of shorter rupture time and more heavy metal adsorption. PBAT degraded faster, absorbed and released more heavy metals than PE. Under all tested conditions, the heavy metal contents in MPs gradually approached those in soil, which proves that MPs are carriers of heavy metal pollutants. These results may help in assessing the impact of MPs on soil environments and provide a theoretical basis for the standardized propiconazole and plastic film usage.

Taxifolin is known to have multiple biological functions. It has been widely used as a multifunctional food additive, and consequently, the global demand for taxifolin is increasing. The main method for taxifolin production is an extraction from larch wood, but the global resources of larch are limited. Astilbin, taxifolin-3-o-rhamnoside, is abundant in many plants and much more readily available, meaning taxifolin can be obtained by deglycosylation of astilbin. In this study, a fungal strain, Aspergillus fumigatus SQH4, was isolated from an enrichment culture of Smilax glabra rhizome to achieve the deglycosylation reaction. A culture of SQH4, adjusted to pH 6.5, with 5 g/L astilbin achieved a yield of taxifolin of 91.3% after biotransformation for 14 h at 35 °C. These findings offer an alternative method for the production of taxifolin.

This was the first study to perform correlation analysis to determine the relationships between tertiary structural and rheological properties of the myofibrillar proteins (MPs) under ultrasound treatment (UT, frequency 20 kHz, power 500 W, intensity 30 %) for 0, 2, 4, 6, 8, and 10 min. The objectives of this study were to 1) characterize the changes of the small and large deformation rheological properties of MPs based on the tertiary structural changes; 2) determine relationships of rheological property, tertiary structural changes, and UT time. The results showed that UT could enhance the structural rigidity and the resistance of the system to permanent deformation observed in rheological tests. Besides, UT could unfold MPs, expose more hydrophobic amino acid residues to increase the surface hydrophobicity (S0-BPB), destroy disulfide bonds to increase the content of reactive sulfhydryl content (R-SH). The correlation analysis showed that the rheological properties of MPs could be improved by UT with a longer treatment time (0-10 min), while inevitably and significantly changing the tertiary structure of MPs (p < 0.05). These findings suggested that UT might be effective in the food-processing industry to change the structure of proteins and improve rheological properties.

Trichiurus lepturus (hairtail) is an important economic component of China’s marine fishing industry. However, due to the difficulty in identifying the appearance of hairtail from different geographical distributions, hairtails with geographical indication trademarks were imitated by general varieties. In this study, the texture characteristics, color, basic nutrients, amino acids, mineral, fatty acids, and volatile flavor substances were used as indicators for multivariate statistical analysis to determine whether three origins of hairtails from the habitats of Zhoushan (East China Sea, T.Z), Hainan (South China Sea, T.N), and Qingdao (Yellow Sea, T.Q) in the market could be distinguished. The findings revealed that there were significant differences in amino acids composition, mineral composition, fatty acid composition in lipids, and volatile flavor substances among the hairtails of three origins (P < 0.05), but no differences in color, texture, protein content. T.Z had moisture, crude fat, essential amino acids (EAA), flavor amino acids (FAA), unsaturated fatty acids (UFA), and docosahexaenoic acids and dicosapentaenoic acids (ΣEPA + DHA) contents of 74.33, 5.4%, 58.25 mg⋅g–1, 46.20 mg⋅g–1, 66.84 and 19.38%, respectively, and the contents of volatile alcohols, aldehydes and ketones were 7.44, 5.30, and 5.38%, respectively. T.N contains moisture, crude fat, EAA, FAA, UFA and ΣEPA + DHA as 77.69, 2.38%, 64.76 mg⋅g–1, 52.44 mg⋅g–1, 65.52 and 29.45%, respectively, and the contents of volatile alcohols, aldehydes and ketones as 3.21, 8.92, and 10.98%, respectively. T.Q had the contents of moisture, crude fat, EAA, FAA, UFA, and ΣEPA + DHA 79.69, 1.43%, 60.9 mg⋅g–1, and 49.42 mg⋅g–1, respectively. The contents of unsaturated fatty acid and ΣEPA + DHA were 63.75 and 26.12%, respectively, while the volatile alcohols, aldehydes, and ketones were 5.14, 5.99, and 7.85%, respectively. Partial least squares-discriminant analysis (PLS-DA) multivariate statistical analysis showed that volatile flavor compounds could be used as the most ideal indicators for tracing the source of hairtail. In conclusion, the findings of this study can distinguish the three hairtail origins using some basic indicators, providing ideas for hairtail geographical identification.

传统的固相萃取和过膜技术存在操作繁琐、耗时长等问题.本文通过优化相关技术参数,整合通过式固相萃取(PRiME)和微孔滤膜技术,实现进样前操作步骤一体化.利用液相色谱串联质谱建立鱼肉中盐酸小檗碱和盐酸氯苯胍的定量检测方法.方法验证试验结果显示:盐酸小檗碱和盐酸氯苯胍在质量浓度0.5～100μg/L范围内线性关系良好,检出限(LOD)分别是0.51μg/kg和0.53μg/kg,定量限(LOQ)分别是1.67μg/kg和1.68μg/kg,日内精密度相对标准偏差范围分别为4.09％～4.48％和3.84％～3.90％,日间精密度相对标准偏差范围为5.17％～5.73％和4.23％～5.29％.在5,10,50μg/kg 3个水平下,盐酸小檗碱和盐酸氯苯胍的回收率范围分别为91.2％～93.2％和91.3％～92.4％;RSD范围分别为4.5％～4.6％和1.8％～5.2％.采用液相色谱串联质谱法测定市售活鱼中目标化合物残留,未检出阳性样品,说明盐酸小檗碱和盐酸氯苯胍在水产养殖方面使用情况良好,该检测方法符合痕量分析的要求.

As a high-value processed aquatic product, wet-aged tuna has gradually become a popular food, but its lipidomics characteristics during the aging process have not been investigated. Herein, the lipidomics phenotypic data of tuna at different wet-aging stages were acquired using iKnife rapid evaporative ionization mass spectrometry, in which the dominant lipid components, including fatty acid (FA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI), were structurally identified. Principal component analysis, permutation test, heatmap, and circos plot analysis were performed to characterize lipids in wet-aged tuna, among which FAC18:1, docosahexaenoic acid (DHA), and PIC18:0/22:6 were the most contributing components for determining the wet-aging stage of tuna. The results indicated that iKnife-REIMS is accurate (86.5%), reliable, and could be used in the real-time detection of tuna meat during different wet-aging stages.

Minced shrimp is popular seafood due to its delicious flavor and nutritional value. However, the biological species of raw material of minced shrimp are not distinguished by naked eyes after processing. Thus, an in situ and real-time minced shrimp authentication method was established using iKnife rapid evaporative ionization mass spectrometry (REIMS) based lipidomics. The samples were analyzed under ambient ionization without any tedious preparation step. Seven economic shrimp samples were tested, whose phenotypes were used to develop a real-time recognition model. A total of 19 fatty acids and 45 phospholipid molecular species were efficiently identified and statistically analyzed by multivariate statistical analysis. The results showed that the seven shrimp species were well distinguished, and the most contributing ions at m/z 255.2, 279.2, 301.2, 327.2, 699.5, 742.5, etc., were revealed by variable importance in projection. The proposed iKnife REIMS showed excellent performance in minced shrimp authentication.

为提高金枪鱼副产物的利用率,减少资源浪费,本试验基于1,2-二氯乙烷体系结合丙酮沉淀法,建立从金枪鱼副产物中同时提取脂质和鱼油的新方法.采用气相色谱法和液相色谱-质谱联用法分别对提取脂质中鱼油和磷脂进行脂质组学研究.通过调节溶剂体系得到1,2-二氯乙烷-甲醇的最佳体积比为1:2.进一步优化提取条件,得到磷脂和鱼油的得率分别为0.944％和17.306％.利用气相色谱法分析甲酯化的鱼油中的脂肪酸甲酯成分,同时在负离子全扫描模式下利用液相色谱-质谱联用技术对磷脂分子进行分离鉴定和相对定量分析.结果显示:鱼油中主要含有DHA、棕榈酸、油酸、EPA等18种脂肪酸,其中多不饱和脂肪酸占36.678％.从磷脂样品中共检出16种磷脂酰胆碱,14种磷脂酰乙醇胺,11种磷脂酰肌醇和12种磷脂酰丝氨酸,同时,结果显示所有磷脂分子种中包含ω-3多不饱和脂肪酸链的磷脂所占比例较高.研究表明,基于1,2-二氯乙烷的提取方法可提取金枪鱼副产物中的磷脂和鱼油,相比传统方法更安全,更适用于食品加工业.