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为研究亚麻籽炒籽过程中形成的美拉德产物（MRPs）以及提高低温压榨亚麻籽油的氧化稳定性，将3种还原糖（葡萄糖、果糖和木糖）与磷脂酰乙醇胺（PE）进行模拟反应，探究反应温度、反应时间和底物物质的量比对MRPs抗氧化活性的影响，利用质谱分析MRPs的主要成分，并考察MRPs对低温压榨亚麻籽油氧化稳定性和醛类化合物形成的影响。结果表明：PE-木糖体系的MRPs具有最高的体外抗氧化能力，其最适反应条件为PE与木糖物质的量比1∶ 1、反应温度160 ℃、反应时间60 min，在该条件下MRPs （2 mg/mL）DPPH自由基清除率达79.57%，铁离子还原抗氧化能力（FRAP）为43.65 μmol/g，铁离子螯合能力为13.34%；通过质谱分析发现由一分子木糖和一分子PE反应形成的PE-吡咯-2-甲醛为MRPs中的主要成分；在190 ℃加速氧化实验中，PE-木糖体系的MRPs对低温压榨亚麻籽油过氧化值和p-茴香胺值的增长表现出与TBHQ相似的抑制作用，同时核磁共振氢谱分析结果表明MRPs可以减缓单烯醛和二烯醛的生成。综上，MRPs可以有效提高油脂的氧化稳定性。In order to study the formation of Maillard reaction products（MRPs） during flaxseed frying and improve the oxidative stability of cold-pressed flaxseed oil, three reducing sugars (glucose, fructose and xylose) were simulated to react with phosphatidylethanolamine (PE), and the effects of reaction temperature, reaction time and molar ratio of substrate on the antioxidant activity of MRPs were investigated. The main components of the MRPs were analyzed by mass spectrometry, and the effects of the MRPs on the oxidative stability and formation of aldehydes of cold-pressed flaxseed oil were investigated.The results showed that the MRPs of PE-xylose system had the highest in vitro antioxidant capacity, and its optimal reaction conditions were molar ratio of xylose to PE 1∶ 1, reaction temperature 160 ℃, and reaction time 60 min. The DPPH radical scavenging rate of the MRPs (2 mg/mL) prepared under the optimal conditions reached 79.57%, the ferric reducing antioxidant capacity (FRAP) was 43.65 μmol/g, and the chelating capacity of iron ions was13.34%; the PE-pyrrole-2-carbaldehyde formed by the reaction of one molecule of xylose and one molecule of PE was found to be the main component in the MRPs by mass spectrometry analysis. In the accelerated oxidation experiment at 190 ℃, the MRPs of PE-xylose system showed similar inhibitory effects to TBHQ on the increase of peroxide value and p-anisidine value of cold-pressed flaxseed oil, while the 1H nuclear magnetic resonance results showed that the MRPs could slow down the generation of monoolefin and dienal. In conclusion, MRPs can effectively improve the oxidative stability of oil.

为研究亚麻籽热榨过程中美拉德反应形成的物质类型及其抗氧化效果，以亚麻籽为原料，在120~200 ℃下炒籽10~30 min并提取亚麻籽油，考察不同炒籽条件下亚麻籽油的氧化稳定性，分析炒籽前后亚麻籽脱脂粉中还原糖和游离氨基酸含量变化，确定美拉德模拟体系的反应底物。以抗氧化活性为指标，对美拉德模拟反应条件进行优化，并考察美拉德反应产物（MRPs）对冷榨亚麻籽油氧化稳定性的影响。结果表明：在180 ℃条件下炒籽20 min制备的亚麻籽油氧化稳定性最好；美拉德模拟反应的最优条件为葡萄糖与赖氨酸物质的量比3∶ 1、反应温度180 ℃、反应时间105 min和葡萄糖与精氨酸物质的量比1∶ 1、反应温度180 ℃、反应时间105 min；两种MRPs对冷榨亚麻籽油过氧化值增长没有明显的抑制效果，而对p-茴香胺值的增长有一定的抑制作用。赖氨酸、精氨酸和葡萄糖的美拉德反应对提高热榨亚麻籽油的氧化稳定性起关键作用，其MRPs对冷榨亚麻籽油具有一定的抗氧化作用。 In order to study the types of substances formed by Maillard reaction during flaxseed hot pressing and their antioxidant effects, flaxseed was roasted at 120-200 ℃ for 10-30 min, and flaxseed oil was extracted. The oxidation stability of flaxseed oil under different roasting conditions was investigated. The changes of reducing sugar and free amino acid content in flaxseed before and after roasting were analyzed, and the reaction substrates of Maillard model system were confirmed. Taking antioxidant activity as an index, Maillard reaction conditions were optimized, and the effects of Maillard reaction products (MRPs) on the oxidative stability of cold pressed flaxseed oil were investigated. The results showed that the flaxseed oil prepared by roasting seeds at 180 ℃ for 20 min had the best oxidation stability. The optimal conditions for Maillard model reaction were obtained as follows：molar ratio of glucose to lysine 3∶ 1, reaction temperature 180 ℃, reaction time 105 min, and molar ratio of glucose to arginine 1∶ 1, reaction temperature 180 ℃, reaction time 105 min. The two MRPs had no significant inhibitory effect on the peroxide value of cold pressed flaxseed oil, while they had some inhibitory effect on the growth of p-anisidine value. The reaction of lysine, arginine and glucose mainly plays an antioxidant role in roasting flaxseed, and its MRPs has a certain antioxidant effect on cold pressed flaxseed oil.

Copyright of South China Fisheries Science is the property of South China Fisheries 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.)

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Copyright of Journal of South China Normal University (Natural Science Edition) / Huanan Shifan Daxue Xuebao (Ziran Kexue Ban) is the property of Journal of South China Normal University (Natural Science Edition) 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 Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui 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 Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui 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.)

Firstly, the metabolites in plasma were extracted to obtain organic and aqueous phases by Folch method. Several kinds of metabolites in organic and aqueous phases were detected simultaneously by ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). Mobile phase and elution procedure were optimized. Chromatographic separation was performed on a ACE3 C18 column (150 mm×3.0 mm×3.0 μm), and the MS analysis was carried out by electrospray ionization (ESI) source in positive and negative ion modes combined with full and segmental scanning. The mass spectrometry-based molecular networking (MSMN) has been widely used, but it has not been mentioned in the analysis of lipid metabolites. In this study, the method for the analysis of metabolites in plasma by UPLC-HRMS combined with MSMN was developed. The metabolites identified by chemical standards were selected as seed compounds, and MSMN was used to screen the metabolites having similar MS/MS behavior with the seed compounds, so as to expand the qualitative range and improve the qualitative efficiency of metabolites. A total of 187 metabolites were annotated, including 80 metabolites such as amino acid, fatty acid and sugar in the aqueous phase and 107 lipid metabolites in the organic phase, among which 64 metabolites were identified by MSMN, which achieved the high throughput analysis of multiple metabolites in human plasma in this way. It provided a feasible new idea for the identification of lipid metabolites but there were still many limitations and challenges. The MSMN is suitable for the analysis of metabolites with large molecular weight, and the prerequisite is that the MS/MS of certain metabolites contains at least 3 or more common characteristic fragments. In this work, the metabolites identified by MSMN in the organic phase were mostly phosphatidylcholines (PCs) and sphingomyelins (SMs) in positive ion mode. For example, the aggregation degree of triacylglycerols (TGs) was high in the MSMN, but it was difficult to annotate successfully because of the weak characteristic of common fragments. However, in negative ion mode, it was more difficult to use MSMN to characterize the metabolites because of the small number of characteristic fragments of congener metabolites and the low mass spectral response of some fragments, which was difficult to be detected. We also tried to establish the MSMN of metabolites in the aqueous phase and obtained the molecular network diagram with good aggregation. However, the qualitative results were not satisfactory, and the metabolites in the aqueous phase were all small molecular weight metabolites such as amino acid, and the MS/MS lacked representative characteristic fragments, so MSMN was not suitable for these metabolites. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University 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 Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui 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 South China Normal University (Natural Science Edition) / Huanan Shifan Daxue Xuebao (Ziran Kexue Ban) is the property of Journal of South China Normal University (Natural Science Edition) 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 Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics 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.)