英国学生科学读本 第95期:面粉与面包(2)

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　　The husks are hard and coarse, and they would not be good food for us, for we could not digest them. 外皮坚硬且粗糙, 我们消化不了, 因此不适合用作食物。

　　Last of all, the miller² puts the white flour into sacks, and sells it to the baker³. 最后, 磨坊主将白色的面粉装在麻袋中销售给面包房。

　　Shall we try to find out what wheat-flour is made of? 你是否想要知道小麦粉是由什么构成的呢?

　　Put a handful of the flour into a small bag made of fine muslin: 拿起一把面粉, 放入精致的棉布中；

　　tie up the mouth of this bag tightly, and then squeeze it for about five minutes in a basin of water. 将棉布做成口袋装并收紧袋口, 然后在一盆清水中用力挤压五分钟。

　　You will see that the water becomes quite white. 你会发现清水将变成非常浓厚的白色。

　　Something must be coming out of the flour and passing through the muslin into the water. What can it be? 肯定有什么东西从面粉中分离出来, 透过棉布进入了水中。到底是什么呢?

　　Let the water in the basin stand for an hour, and you will then find a white powder at the bottom. 将盆中的水静置一小时, 就会看到水底有一层白色粉末。

　　Pour off the water, and put the white stuff into a saucer to dry on the hob or in the oven. 将水倒掉, 把白色物质放入浅碟之中, 利用铁架或火炉进行烘干。

　　If you mix a little of this dry white powder with a spoonful of boiling water, it swells⁴ up into a jelly just like starch⁵; 如果你将少量这种干燥的白色粉末与一勺开水相混合, 它就会像淀粉一样膨胀成胶状物；

　　indeed, the white powder is starch and nothing else. 实际上, 这种白色粉末正是淀粉。

　　So we see that flour contains a great deal of starch. 由此我们知道, 面粉中含有大量的淀粉。

　　Now open the muslin bag in which you washed the flour. 现在, 打开那个冲洗过面粉的棉布包。

　　Is there anything left inside it ? 里面还有什么剩余物质吗?

　　Yes; there is a small quantity of a yellowish-white and very sticky substance. 有, 我们可以看到少量黄白色的粘稠物质。

　　The proper name for this sticky stuff is gluten. 这种东西的正式名称就是面筋。

　　We may say, then, that flour consists of starch and gluten. 由此我们就可以说, 面粉中包括淀粉与小麦蛋白。

　　But it also contains some water, and a very little lime which the roots of the wheat plant sucked in from the soil. 不过, 这其中还有一些水分以及小麦的根部从土壤中吸收到的极少量碳酸盐。

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