各种食物所含维生素的种类和数量不同,它们的营养价值就不同。不同维生素的耐酸碱性、耐热性、溶解性、氧化性以及对光的敏感性不同,也就是性质也不尽相同,故食维生素食物有许多学问。含维生素 C 丰富的绿色蔬菜、辣椒、西红柿等,烹饪...各种食物所含维生素的种类和数量不同,它们的营养价值就不同。不同维生素的耐酸碱性、耐热性、溶解性、氧化性以及对光的敏感性不同,也就是性质也不尽相同,故食维生素食物有许多学问。含维生素 C 丰富的绿色蔬菜、辣椒、西红柿等,烹饪时易快炒、轻炒。维生素 C 不耐热,且忌碱。含叶酸(B<sub>11</sub>)和泛酸（B<sub>3</sub>）丰富的叶菜类,烹饪时忌酸,因为它们在酸性液中易被热破坏。含有维生素 B<sub>1</sub>、展开更多
The dynamic changes in the distribution of lignin and hemicelluloses (xylans and xyloglucans) in cell walls during the differentiation of secondary xylem in Eucommia ulmoides Oliv. were studied by means of ultraviolet...The dynamic changes in the distribution of lignin and hemicelluloses (xylans and xyloglucans) in cell walls during the differentiation of secondary xylem in Eucommia ulmoides Oliv. were studied by means of ultraviolet light microscopy and transmission electron microscopy combined with immunogold labelling. In the cambial zone and cell expansion zone, xyloglucans were localized both in the tangential and radial walls, but no xylans or lignin were found in these regions. With the formation of secondary wall S-1 layer, lignin occurred in the cell corners and middle lamella, while xylans appeared in S-1 layer, and xyloglucans were localized in the primary walls and middle lamella. In pace with the formation of secondary wall S-2 and S-3 layer, lignification extended to S-1, S-2 and S-3 layer in sequence, showing a patchy style of lignin deposition. Concurrently, xylans distributed in the whole secondary walls and xyloglucans, on the other hand, still localized in the primary walls and middle lamella. The results indicated that along with the formation and lignification of the secondary wall, great changes had taken place in the cell walls. Different parts of cell walls, such as cell corners, middle lamella, primary walls and various layers of secondary walls, had different kinds of hemicelluloses, which formed various cell wall architecture combined with lignin and other cell wall components.展开更多
1.久存蔬菜:新鲜的青菜,买来存在家里不吃,便会慢慢损失一些维生素,如菠菜在20℃时,维生素 C 损失达84%。若要保存蔬菜,应在避光、通风、干燥的地方贮存。2.丢弃了含维生素最丰富的部分:例如豆芽,有人在吃时只吃上面的芽,而将豆子丢掉...1.久存蔬菜:新鲜的青菜,买来存在家里不吃,便会慢慢损失一些维生素,如菠菜在20℃时,维生素 C 损失达84%。若要保存蔬菜,应在避光、通风、干燥的地方贮存。2.丢弃了含维生素最丰富的部分:例如豆芽,有人在吃时只吃上面的芽,而将豆子丢掉。事实上,豆中含维生素 C 比芽的部分多2～3倍。再有,做饺子馅,把菜汁挤掉,维生素会损失70%以上。正确的方法是,切好菜后用油拌好,再加盐和调料,这样油包菜,盐分进不去,馅就不会出汤。3.先切菜再冲洗:在洗切青菜时,有人往往先切再洗,殊不知青菜中的维生素大都能溶解于水,若将菜切了再冲洗,大量维生素就会流失到水中。4.展开更多
文摘各种食物所含维生素的种类和数量不同,它们的营养价值就不同。不同维生素的耐酸碱性、耐热性、溶解性、氧化性以及对光的敏感性不同,也就是性质也不尽相同,故食维生素食物有许多学问。含维生素 C 丰富的绿色蔬菜、辣椒、西红柿等,烹饪时易快炒、轻炒。维生素 C 不耐热,且忌碱。含叶酸(B<sub>11</sub>)和泛酸（B<sub>3</sub>）丰富的叶菜类,烹饪时忌酸,因为它们在酸性液中易被热破坏。含有维生素 B<sub>1</sub>、
文摘The dynamic changes in the distribution of lignin and hemicelluloses (xylans and xyloglucans) in cell walls during the differentiation of secondary xylem in Eucommia ulmoides Oliv. were studied by means of ultraviolet light microscopy and transmission electron microscopy combined with immunogold labelling. In the cambial zone and cell expansion zone, xyloglucans were localized both in the tangential and radial walls, but no xylans or lignin were found in these regions. With the formation of secondary wall S-1 layer, lignin occurred in the cell corners and middle lamella, while xylans appeared in S-1 layer, and xyloglucans were localized in the primary walls and middle lamella. In pace with the formation of secondary wall S-2 and S-3 layer, lignification extended to S-1, S-2 and S-3 layer in sequence, showing a patchy style of lignin deposition. Concurrently, xylans distributed in the whole secondary walls and xyloglucans, on the other hand, still localized in the primary walls and middle lamella. The results indicated that along with the formation and lignification of the secondary wall, great changes had taken place in the cell walls. Different parts of cell walls, such as cell corners, middle lamella, primary walls and various layers of secondary walls, had different kinds of hemicelluloses, which formed various cell wall architecture combined with lignin and other cell wall components.
文摘1.久存蔬菜:新鲜的青菜,买来存在家里不吃,便会慢慢损失一些维生素,如菠菜在20℃时,维生素 C 损失达84%。若要保存蔬菜,应在避光、通风、干燥的地方贮存。2.丢弃了含维生素最丰富的部分:例如豆芽,有人在吃时只吃上面的芽,而将豆子丢掉。事实上,豆中含维生素 C 比芽的部分多2～3倍。再有,做饺子馅,把菜汁挤掉,维生素会损失70%以上。正确的方法是,切好菜后用油拌好,再加盐和调料,这样油包菜,盐分进不去,馅就不会出汤。3.先切菜再冲洗:在洗切青菜时,有人往往先切再洗,殊不知青菜中的维生素大都能溶解于水,若将菜切了再冲洗,大量维生素就会流失到水中。4.
