为探究大豆分离蛋白(Soy protein isolate,SPI)与双醛羧甲基纤维素(Dialdehyde carboxymethyl cellulose,DCMC)发生席夫碱交联反应对大豆蛋白凝胶结构和功能特性的影响,文章采用不同羧甲基取代度(DS=0.7、0.9和1.2)的DCMC制备SPI-DCMC...为探究大豆分离蛋白(Soy protein isolate,SPI)与双醛羧甲基纤维素(Dialdehyde carboxymethyl cellulose,DCMC)发生席夫碱交联反应对大豆蛋白凝胶结构和功能特性的影响,文章采用不同羧甲基取代度(DS=0.7、0.9和1.2)的DCMC制备SPI-DCMC热诱导交联凝胶,分析不同羧甲基取代度的DCMC醛基变化规律,分析凝胶的内源荧光光谱、FTIR光谱、XPS能谱和ABTS^(+)自由基清除率。结果表明,凝胶的荧光强度随着取代度的增加而增大,在DS=0.7时,荧光强度最低,席夫碱交联度最高。FTIR光谱证实交联改变SPI二级结构。XPS表现出DS=0.7时,C=N键峰面积最大,席夫碱反应程度最高。当DS自0.7增至1.2时,ABTS^(+)自由基清除率由72.26%±4.31%降至58.72%±3.30%。展开更多
文章以小麦醇溶蛋白(Gliadin,G)、大豆分离蛋白(Soy protein isolate,SPI)和海藻酸钠(Sodium alginate,SA)为原料,通过pH驱动技术制备纳米颗粒,探讨添加SA对蛋白质纳米颗粒结构和性质的影响,并将其应用于虾青素(Astaxanthin,ASTA)运输...文章以小麦醇溶蛋白(Gliadin,G)、大豆分离蛋白(Soy protein isolate,SPI)和海藻酸钠(Sodium alginate,SA)为原料,通过pH驱动技术制备纳米颗粒,探讨添加SA对蛋白质纳米颗粒结构和性质的影响,并将其应用于虾青素(Astaxanthin,ASTA)运输体系。结果表明,添加SA后,蛋白质纳米颗粒粒径减小、Zeta电位绝对值增大,空间结构改变,稳定性和ASTA包封能力提高。通过分析优选4∶1(蛋白质∶SA)比例制备蛋白质纳米颗粒,粒径为133.32 nm、zeta电位为-38.56 mV、ASTA包封率为85.45%。稳定性和抗氧化性试验表明,SA/G/SPI-ASTA纳米颗粒抗环境胁迫和抗氧化能力更佳(DPPH清除率为69.57%,ABTS清除率为85.80%)。展开更多
Diacylglycerol(DAG)is a functional oil that can reduce body fat accumulation and postprandial triglycerides.In this study,lipase-catalyzed esterification of oleic acid with glycerol was investigated to elucidate the k...Diacylglycerol(DAG)is a functional oil that can reduce body fat accumulation and postprandial triglycerides.In this study,lipase-catalyzed esterification of oleic acid with glycerol was investigated to elucidate the kinetics and selectivity of each reaction step.1H NMR monitoring revealed equilibrated positional isomerization among acylglycerols:sn-1 monoolein comprised 97.3%of total monoacylglycerols,and sn-1,3 diolein comprised 73.3%of total diacylglycerols.Acyl migration(isomer equilibration)occurred faster than overall esterification.The observed rate constants for successive esterification steps(glycerol→monoacylglycerol,monoacylglycerol→diacylglycerol,diacylglycerol→triacylglycerol)were 0.01068,0.00615,and 0.00304 min^(-1),respectively,indicating progressively slower reaction rates for larger acylglycerol species.Furthermore,molecular distillation at 200–220℃ purified the DAG without altering its fatty acid profile.These findings establish a kinetic model of the three-step esterification and highlight the importance of acyl migration in enzymatic DAG synthesis.展开更多
文摘为探究大豆分离蛋白(Soy protein isolate,SPI)与双醛羧甲基纤维素(Dialdehyde carboxymethyl cellulose,DCMC)发生席夫碱交联反应对大豆蛋白凝胶结构和功能特性的影响,文章采用不同羧甲基取代度(DS=0.7、0.9和1.2)的DCMC制备SPI-DCMC热诱导交联凝胶,分析不同羧甲基取代度的DCMC醛基变化规律,分析凝胶的内源荧光光谱、FTIR光谱、XPS能谱和ABTS^(+)自由基清除率。结果表明,凝胶的荧光强度随着取代度的增加而增大,在DS=0.7时,荧光强度最低,席夫碱交联度最高。FTIR光谱证实交联改变SPI二级结构。XPS表现出DS=0.7时,C=N键峰面积最大,席夫碱反应程度最高。当DS自0.7增至1.2时,ABTS^(+)自由基清除率由72.26%±4.31%降至58.72%±3.30%。
基金Bureau of Science and Information of Guangzhou under grant 2024A04J3254the National Key Research and Development Program of China under grant 2024YFE0214900+2 种基金the National Natural Science Foundation of China under grant 32272341,he National Key Research and Development Program of China under grant 2023YFD2100401the Opening Project of Hubei Key Laboratory of Lipid Chemistry and Nutrition under grant 202401,are gratefully acknowledged.
文摘Diacylglycerol(DAG)is a functional oil that can reduce body fat accumulation and postprandial triglycerides.In this study,lipase-catalyzed esterification of oleic acid with glycerol was investigated to elucidate the kinetics and selectivity of each reaction step.1H NMR monitoring revealed equilibrated positional isomerization among acylglycerols:sn-1 monoolein comprised 97.3%of total monoacylglycerols,and sn-1,3 diolein comprised 73.3%of total diacylglycerols.Acyl migration(isomer equilibration)occurred faster than overall esterification.The observed rate constants for successive esterification steps(glycerol→monoacylglycerol,monoacylglycerol→diacylglycerol,diacylglycerol→triacylglycerol)were 0.01068,0.00615,and 0.00304 min^(-1),respectively,indicating progressively slower reaction rates for larger acylglycerol species.Furthermore,molecular distillation at 200–220℃ purified the DAG without altering its fatty acid profile.These findings establish a kinetic model of the three-step esterification and highlight the importance of acyl migration in enzymatic DAG synthesis.
