英國學(xué)生科學(xué)讀本 Lesson 95 面粉與面包(2)

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然后, 人們利用篩子將面粉與外皮分離。

The husks are hard and coarse, and they would not be good food for us, for we could not digest them.

外皮堅(jiān)硬且粗糙, 我們消化不了, 因此不適合用作食物。

Last of all, the miller puts the white flour into sacks, and sells it to the baker.

最后, 磨坊主將白色的面粉裝在麻袋中銷售給面包房。

Shall we try to find out what wheat-flour is made of?

你是否想要知道小麥粉是由什么構(gòu)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.

將棉布做成口袋裝并收緊袋口, 然后在一盆清水中用力擠壓五分鐘。

You will see that the water becomes quite white.

你會(huì)發(fā)現(xiàn)清水將變成非常濃厚的白色。

Something must be coming out of the flour and passing through the muslin into the water. What can it be?

肯定有什么東西從面粉中分離出來, 透過棉布進(jìn)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.

將盆中的水靜置一小時(shí), 就會(huì)看到水底有一層白色粉末。

Pour off the water, and put the white stuff into a saucer to dry on the hob or in the oven.

將水倒掉, 把白色物質(zhì)放入淺碟之中, 利用鐵架或火爐進(jìn)行烘干。

If you mix a little of this dry white powder with a spoonful of boiling water, it swells up into a jelly just like starch;

如果你將少量這種干燥的白色粉末與一勺開水相混合, 它就會(huì)像淀粉一樣膨脹成膠狀物;

indeed, the white powder is starch and nothing else.

實(shí)際上, 這種白色粉末正是淀粉。

So we see that flour contains a great deal of starch.

由此我們知道, 面粉中含有大量的淀粉。

Now open the muslin bag in which you washed the flour.

現(xiàn)在, 打開那個(gè)沖洗過面粉的棉布包。

Is there anything left inside it ?

里面還有什么剩余物質(zhì)嗎?

Yes; there is a small quantity of a yellowish-white and very sticky substance.

有, 我們可以看到少量黃白色的粘稠物質(zhì)。

The proper name for this sticky stuff is gluten.

這種東西的正式名稱就是面筋。

We may say, then, that flour consists of starch and gluten.

由此我們就可以說, 面粉中包括淀粉與小麥蛋白。

But it also contains some water, and a very little lime which the roots of the wheat plant sucked in from the soil.

不過, 這其中還有一些水分以及小麥的根部從土壤中吸收到的極少量碳酸鹽。

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