淀粉糊化度(Degree of Starch Gelatinization,DSG)不仅影响含淀粉类食品的物理和感官特性,而且还影响其消化特性和营养特性,如何准确、快速、简便地检测DSG已经成为食品工业界亟待解决的热点问题。本文在国内外相关研究的基础之上,综述...淀粉糊化度(Degree of Starch Gelatinization,DSG)不仅影响含淀粉类食品的物理和感官特性,而且还影响其消化特性和营养特性,如何准确、快速、简便地检测DSG已经成为食品工业界亟待解决的热点问题。本文在国内外相关研究的基础之上,综述了DSG测量方法的原理及准确性,并将几种常用方法的准确性进行了比较。经过系统比较分析,发现利用酶法测定DSG是当前较为合适的测定方法,但其还存在测定程序繁琐、耗时等问题。因此,还需要进一步优化和改进酶法,使其能够成为DSG快速、准确、广谱的测定方法。展开更多
本实验以未经乙醇溶液处理的乳清分离蛋白(Whey protein isolate,WPI)作为对照组,研究不同浓度乙醇(10%、30%、50%和70%,v/v)处理对WPI结构特性和乳化特性的影响。结果表明,乙醇诱导改性会使WPI的二级结构和三级结构发生显著变化。当乙...本实验以未经乙醇溶液处理的乳清分离蛋白(Whey protein isolate,WPI)作为对照组,研究不同浓度乙醇(10%、30%、50%和70%,v/v)处理对WPI结构特性和乳化特性的影响。结果表明,乙醇诱导改性会使WPI的二级结构和三级结构发生显著变化。当乙醇浓度低于50%时可以使蛋白结构展开,而乙醇浓度高于50%时会使WPI分子之间通过二硫键形成聚合物。另外,与对照组相比,乙醇改性能够赋予WPI更高的表面疏水性和更佳的乳化特性(包括乳化活性和乳化稳定性),且乙醇浓度为50%时改善效果最为显著(P<0.05)。上述研究结果表明,乙醇诱导改性是一种有效的改善WPI乳化特性的改性方法,从而为蛋白质的改性奠定了理论基础。展开更多
Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge.The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfil...Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge.The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfill this purpose.In this study,the release of Suomi-NPP Cross-track Infrared Sounder(Cr IS)full spectrum resolution is used to select and pair channels from longwave(~15μm)and shortwave(~4.3μm)CO2 absorption bands under stricter conditions,so as to better detect ice clouds.Besides,the differences of the weighting function peaks and cloud insensitive level altitudes of the paired channels are both within 50 h Pa so that the variances due to atmospheric conditions can be minimized.The training data of clear sky are determined by Visible Infrared Imaging Radiometer Suite(VIIRS)cloud mask product and used to find the linear relationship between the paired longwave and shortwave CO2 absorption channels.From the linear relationship,the so-called cloud emission and scattering index(CESI)is derived to detect ice clouds.CESI clearly captures the center and the ice cloud features of the Super Typhoon Hato located above 415 h Pa.Moreover,the CESI distributions agree with cloud top pressure from the VIIRS in both daytime and nighttime in different atmospheric layers.展开更多
基于涡度相关系统,并引入O3损耗半机制模型,分析了南京地区冬小麦主要生育期总初级生产力(GPP)的变化,并模拟了不同O3含量胁迫条件下冬小麦GPP的损耗.结果表明:①冬小麦GPP随其生育期变化,呈现出'中间时段高,前后期低'的分布趋...基于涡度相关系统,并引入O3损耗半机制模型,分析了南京地区冬小麦主要生育期总初级生产力(GPP)的变化,并模拟了不同O3含量胁迫条件下冬小麦GPP的损耗.结果表明:①冬小麦GPP随其生育期变化,呈现出'中间时段高,前后期低'的分布趋势,最大值为40μmol·(m2·s)-1;②基于高、低两种O3敏感度效应,150、100和50 n L·L-1组和本研究(CK组)胁迫条件下,冬小麦GPP损耗率分别为:-72%、-36%、-6%、-10%和-13%、-6%、-1%、-2%.损耗评估结果可为我国制定防御O3对作物伤害对策提供科学依据.展开更多
文摘淀粉糊化度(Degree of Starch Gelatinization,DSG)不仅影响含淀粉类食品的物理和感官特性,而且还影响其消化特性和营养特性,如何准确、快速、简便地检测DSG已经成为食品工业界亟待解决的热点问题。本文在国内外相关研究的基础之上,综述了DSG测量方法的原理及准确性,并将几种常用方法的准确性进行了比较。经过系统比较分析,发现利用酶法测定DSG是当前较为合适的测定方法,但其还存在测定程序繁琐、耗时等问题。因此,还需要进一步优化和改进酶法,使其能够成为DSG快速、准确、广谱的测定方法。
文摘本实验以未经乙醇溶液处理的乳清分离蛋白(Whey protein isolate,WPI)作为对照组,研究不同浓度乙醇(10%、30%、50%和70%,v/v)处理对WPI结构特性和乳化特性的影响。结果表明,乙醇诱导改性会使WPI的二级结构和三级结构发生显著变化。当乙醇浓度低于50%时可以使蛋白结构展开,而乙醇浓度高于50%时会使WPI分子之间通过二硫键形成聚合物。另外,与对照组相比,乙醇改性能够赋予WPI更高的表面疏水性和更佳的乳化特性(包括乳化活性和乳化稳定性),且乙醇浓度为50%时改善效果最为显著(P<0.05)。上述研究结果表明,乙醇诱导改性是一种有效的改善WPI乳化特性的改性方法,从而为蛋白质的改性奠定了理论基础。
基金National Key R&D Program(2018YFC1506904)Natural Science Foundation of China(41590873,41705089)。
文摘Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge.The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfill this purpose.In this study,the release of Suomi-NPP Cross-track Infrared Sounder(Cr IS)full spectrum resolution is used to select and pair channels from longwave(~15μm)and shortwave(~4.3μm)CO2 absorption bands under stricter conditions,so as to better detect ice clouds.Besides,the differences of the weighting function peaks and cloud insensitive level altitudes of the paired channels are both within 50 h Pa so that the variances due to atmospheric conditions can be minimized.The training data of clear sky are determined by Visible Infrared Imaging Radiometer Suite(VIIRS)cloud mask product and used to find the linear relationship between the paired longwave and shortwave CO2 absorption channels.From the linear relationship,the so-called cloud emission and scattering index(CESI)is derived to detect ice clouds.CESI clearly captures the center and the ice cloud features of the Super Typhoon Hato located above 415 h Pa.Moreover,the CESI distributions agree with cloud top pressure from the VIIRS in both daytime and nighttime in different atmospheric layers.
文摘基于涡度相关系统,并引入O3损耗半机制模型,分析了南京地区冬小麦主要生育期总初级生产力(GPP)的变化,并模拟了不同O3含量胁迫条件下冬小麦GPP的损耗.结果表明:①冬小麦GPP随其生育期变化,呈现出'中间时段高,前后期低'的分布趋势,最大值为40μmol·(m2·s)-1;②基于高、低两种O3敏感度效应,150、100和50 n L·L-1组和本研究(CK组)胁迫条件下,冬小麦GPP损耗率分别为:-72%、-36%、-6%、-10%和-13%、-6%、-1%、-2%.损耗评估结果可为我国制定防御O3对作物伤害对策提供科学依据.
