A novel central hole-expansion phenomenon is identified, in which the cation-exchange resin is pyrolyzed in a mixed atmosphere of nitrogen and oxygen at 400–500 ℃. In this reaction, the reaction path is predictable ...A novel central hole-expansion phenomenon is identified, in which the cation-exchange resin is pyrolyzed in a mixed atmosphere of nitrogen and oxygen at 400–500 ℃. In this reaction, the reaction path is predictable and always starts from the center of the resin particle to form a central hole, then continues and expands around the hole, finally forming a uniformly distributed hole group;the particle surface remains intact. Analysis shows that this formation mode is due to the different reaction paths of sulfonic groups between the surface and interior of the particle, caused by the temperature difference. On the surface, transformation reactions happen at high temperatures(410–500 ℃) to form stable organic sulfur structures, while decomposition occurs inside the particle at a relatively low temperature(<410 ℃) and promotes complete pyrolysis of the copolymer matrix to form holes.展开更多
Corbicula fluminea distillate(CFD),as an industrial sub-product of the steaming process of C.fluminea,is rich in polysaccharides,proteins,and amino acids and has important developmental value.In this study,therefore,t...Corbicula fluminea distillate(CFD),as an industrial sub-product of the steaming process of C.fluminea,is rich in polysaccharides,proteins,and amino acids and has important developmental value.In this study,therefore,three water-soluble polysaccharides(CFDPs:CFDP-D,CFDP-U,and CFDP-T)were extracted and separated from CFD through direct ethanol precipitation,ultrasound-assisted extraction,and three-phase partitioning(TPP),respectively.Results demonstrated that the three extraction methods had important influences on extraction yields,chemical compositions,molecular weights,monosaccharide and amino acid constituents,structural characteristics,and microstructures as well as biological activities of CFDPs.Specifically,CFDP-T had higher yield(60.92%±3.58%),carbohydrate content(91.05%±1.22%),and uronic acid content(8.55%±0.18%)and lower protein content(7.15%±0.15%)than CFDP-D and CFDP-U.The three CFDPs were acidic proteoheteroglycans combined through O-glycosidic bonds and had high molecular weights of 1.93–2.41×10^(7) Da and the same monosaccharide and amino acid compositions but different contents.Compared with CFDP-D and CFDP-U,CFDP-T exhibited more excellent free radical scavenging and stimulating(1.57±0.03μM,500μg/mL)activities on RAW264.7 macrophages in vitro.Therefore,our findings suggested that CFDP-T obtained from CFD by TPP had the potential to be a functional food ingredient in food industry.展开更多
基金supported by the Joint Funds of the National Natural Science Foundation of China (No. U21B2095)the Major Research Project of National Natural Science Foundation of China (No. 91834303)the Science Fund for Creative Research Groups of National Natural Science Foundation of China (No. 61621002)。
文摘A novel central hole-expansion phenomenon is identified, in which the cation-exchange resin is pyrolyzed in a mixed atmosphere of nitrogen and oxygen at 400–500 ℃. In this reaction, the reaction path is predictable and always starts from the center of the resin particle to form a central hole, then continues and expands around the hole, finally forming a uniformly distributed hole group;the particle surface remains intact. Analysis shows that this formation mode is due to the different reaction paths of sulfonic groups between the surface and interior of the particle, caused by the temperature difference. On the surface, transformation reactions happen at high temperatures(410–500 ℃) to form stable organic sulfur structures, while decomposition occurs inside the particle at a relatively low temperature(<410 ℃) and promotes complete pyrolysis of the copolymer matrix to form holes.
基金supported financially by the National Natural Science Foundation of China(31671812)the Policy Guidance Projects in Jiangsu Province(Science and Technology Special Project in Northern Jiangsu Province,SZ-SQ2019038)+1 种基金the Foundation for Innovation Team in Higher Education of Guangdong,China(2021KCXTD035)the program from Institute of Science and Technology Innovation,DGUT(KCYCXPT2017007)。
文摘Corbicula fluminea distillate(CFD),as an industrial sub-product of the steaming process of C.fluminea,is rich in polysaccharides,proteins,and amino acids and has important developmental value.In this study,therefore,three water-soluble polysaccharides(CFDPs:CFDP-D,CFDP-U,and CFDP-T)were extracted and separated from CFD through direct ethanol precipitation,ultrasound-assisted extraction,and three-phase partitioning(TPP),respectively.Results demonstrated that the three extraction methods had important influences on extraction yields,chemical compositions,molecular weights,monosaccharide and amino acid constituents,structural characteristics,and microstructures as well as biological activities of CFDPs.Specifically,CFDP-T had higher yield(60.92%±3.58%),carbohydrate content(91.05%±1.22%),and uronic acid content(8.55%±0.18%)and lower protein content(7.15%±0.15%)than CFDP-D and CFDP-U.The three CFDPs were acidic proteoheteroglycans combined through O-glycosidic bonds and had high molecular weights of 1.93–2.41×10^(7) Da and the same monosaccharide and amino acid compositions but different contents.Compared with CFDP-D and CFDP-U,CFDP-T exhibited more excellent free radical scavenging and stimulating(1.57±0.03μM,500μg/mL)activities on RAW264.7 macrophages in vitro.Therefore,our findings suggested that CFDP-T obtained from CFD by TPP had the potential to be a functional food ingredient in food industry.
