采用工业热改性、工业碱改性、工业糖基化改性、工业氧化改性4种方法对大豆分离蛋白(soybean protein isolate,SPI)进行改性处理,研究其对SPI结构的影响,进而探讨改性蛋白与肌原纤维蛋白(myofibrillar protein,MP)制成的复合凝胶的质构...采用工业热改性、工业碱改性、工业糖基化改性、工业氧化改性4种方法对大豆分离蛋白(soybean protein isolate,SPI)进行改性处理,研究其对SPI结构的影响,进而探讨改性蛋白与肌原纤维蛋白(myofibrillar protein,MP)制成的复合凝胶的质构特性及凝胶特性。结果表明:4种工业改性对SPI亚基组成并未造成显著影响,但是均减少了SPI的α-螺旋和无规卷曲结构相对含量,并增加了β-折叠与β-转角结构相对含量;工业热改性、工业碱改性、工业糖基化改性处理显著增加了SPI的二硫键含量并降低了SPI的游离巯基含量,而工业氧化改性显著降低了SPI的二硫键含量(P<0.05),且4种工业改性处理均改变了SPI的二硫键构型;4种工业改性蛋白的酪氨酸残基均趋向于“暴露式”,工业热改性、工业碱改性、工业糖基化改性处理使色氨酸残基趋向于“暴露”态,而工业氧化改性导致氧化蛋白聚集使色氨酸残基被包埋。SPI-MP复合凝胶的质构特性结果表明,工业热改性、工业碱改性、工业糖基化改性3种改性SPI与MP形成的复合凝胶硬度、弹性等质构特性均显著优于对照SPI(P<0.05),而工业氧化改性SPI形成的混合凝胶除黏结性外各项质构特性均差于对照SPI。观察SPI-MP复合凝胶扫描电镜图可知,工业热改性、工业碱改性、工业糖基化改性SPI形成的复合凝胶更加致密均匀,工业氧化改性SPI与MP形成的复合凝胶粗糙多孔。展开更多
The method to calculate rock pressure to which the lining structure of tunnel with shallow depth is subjected in geologically inclined bedding strata is analyzed and put forward. Both the inclination angle of bedding ...The method to calculate rock pressure to which the lining structure of tunnel with shallow depth is subjected in geologically inclined bedding strata is analyzed and put forward. Both the inclination angle of bedding strata as well as the internal friction angle of bedding plane and its cohesion all exert an influence upon the magnitude of the asymmetric rock pressure applied to tunnel. The feature that rock pressure applied to tunnel structure varies with the incUnation angle of bedding strata is discussed, At last, the safety factor, which is utilized to evaluate the working state of tunnel lining structure, is calculated for both symmetric and asymmetric lining structures. The calculation results elucidate that the asymmetric tunnel structure can be more superior to bear rock pressure in comparison with the symmetric one and should be adopted in engineering as far as possible.展开更多
文摘采用工业热改性、工业碱改性、工业糖基化改性、工业氧化改性4种方法对大豆分离蛋白(soybean protein isolate,SPI)进行改性处理,研究其对SPI结构的影响,进而探讨改性蛋白与肌原纤维蛋白(myofibrillar protein,MP)制成的复合凝胶的质构特性及凝胶特性。结果表明:4种工业改性对SPI亚基组成并未造成显著影响,但是均减少了SPI的α-螺旋和无规卷曲结构相对含量,并增加了β-折叠与β-转角结构相对含量;工业热改性、工业碱改性、工业糖基化改性处理显著增加了SPI的二硫键含量并降低了SPI的游离巯基含量,而工业氧化改性显著降低了SPI的二硫键含量(P<0.05),且4种工业改性处理均改变了SPI的二硫键构型;4种工业改性蛋白的酪氨酸残基均趋向于“暴露式”,工业热改性、工业碱改性、工业糖基化改性处理使色氨酸残基趋向于“暴露”态,而工业氧化改性导致氧化蛋白聚集使色氨酸残基被包埋。SPI-MP复合凝胶的质构特性结果表明,工业热改性、工业碱改性、工业糖基化改性3种改性SPI与MP形成的复合凝胶硬度、弹性等质构特性均显著优于对照SPI(P<0.05),而工业氧化改性SPI形成的混合凝胶除黏结性外各项质构特性均差于对照SPI。观察SPI-MP复合凝胶扫描电镜图可知,工业热改性、工业碱改性、工业糖基化改性SPI形成的复合凝胶更加致密均匀,工业氧化改性SPI与MP形成的复合凝胶粗糙多孔。
文摘The method to calculate rock pressure to which the lining structure of tunnel with shallow depth is subjected in geologically inclined bedding strata is analyzed and put forward. Both the inclination angle of bedding strata as well as the internal friction angle of bedding plane and its cohesion all exert an influence upon the magnitude of the asymmetric rock pressure applied to tunnel. The feature that rock pressure applied to tunnel structure varies with the incUnation angle of bedding strata is discussed, At last, the safety factor, which is utilized to evaluate the working state of tunnel lining structure, is calculated for both symmetric and asymmetric lining structures. The calculation results elucidate that the asymmetric tunnel structure can be more superior to bear rock pressure in comparison with the symmetric one and should be adopted in engineering as far as possible.
