书城外语英国学生科学读本
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第41章 糖是怎么生产的

1.After the negroes have cut up the stems of the sugar-cane into short lengths,they carry these to a building where there are a number of heavy iron rollers,which are turned by a steam-engine.The cane-stems are crushed between these rollers,and all the sweet juice is squeezed out of them,and runs into large pans placed under the rollers.

CRUSHING THE CANE(碾碎甘蔗)

2.This juice is next boiled in large copper kettles,and some lime is mixed with it.The lime joins with the sour acids①that are in the juice,and forms a green scum②,which is taken off.

3.A clear yellow syrup③then remains,and this is boiled until most of the water in it is driven off as steam.A thick brown liquid is now left,which is a mixture of sugar and molasses or treacle.

BOILING THE SUGAR(煮糖浆)

4.This liquid is put into barrels,the bottoms of which are full of holes.The treacle drains away through these holes,and a dark brown sticky powder is left,which is called raw sugar.This raw sugar is put into big barrels called hogsheads,and is sent to Great Britain in ships.

①Acids,sour substances.

②Scum,the worthless part of a liquid,which rises to the top.

③Syrup,a thick,sweet liquid.

5.You would not like to eat the dirty-looking raw sugar as it comes to this country.To make this raw sugar pure and clean,it must be refined①;and this refining is chiefly done in the largetowns called Bristol②,Liverpool,London③,and Glasgow④.

6.The raw sugar is first dissolved in water,and is then carefully strained⑤to make it clear.It is next boiled in large pans until the water has nearly all passed away as steam.

7.Then the thick sugar-syrup is poured into cone-shaped moulds,where it cools.By the time that it is quite cool,the sugar has turned into tiny white solid pieces,called crystals.It is turned out of the moulds in the form of tall cones,which are calledSUGAR CRYSTALS(糖的晶体)sugarloaves.The grocer breaks up these big loaves into small pieces,which he sells as lump-sugar.

8.Sugar is made from the sweet juice of the beet-root in almost exactly the same way as from the sugar-cane.But the beet-roots are not crushed between rollers like the stems of the sugarcane.They are first cut up into slices,and then soaked in water to extract or draw out the juice.

9.You know that sugar is used for making jam,and cakes,and pastry,and all kinds of sweets,as well as for sweetening our tea and coffee.

10.It is only of late years that sugar has become so cheap that every one can afford to use plenty of it.Until about one hundred years ago,sugar was hardly ever used in this country.Before that time people used honey to sweeten things.

①Refined,made fine or pure.

②Bristol,Liverpool,towns in the west of England.

③London,in the south-east of England,is the capital of that country.

④Glasgow,the chief town in the west of Scotland.

⑤Strained,made pure by passing through a sieve or filter.

SUMMARY

The sugar-cane is cut into short lengths,and is crushed between rollers to squeeze out the sweet juice.This juice is then boiled until a thick brown liquid,a mixture of sugar and molasses,is left.The molasses is then drained off,and the raw sugar is left.In this raw state sugar is sent to this country,where it is refined and made into loaf-sugar.To get the sweet juice out of the beet-root,it is cut into slices and then soaked in water.

【中文阅读】

1.黑人工人把甘蔗茎切成小段之后,就把这些小段运到一个车间里。这个车间里有很多沉重的铁滚筒,是让蒸汽机转动的。滚筒把甘蔗段碾碎,所有的甜汁都从里面挤了出来,流到滚筒下面的大型平底锅里。①2.然后,用大型的铜壶把甘蔗汁煮一遍,往甘蔗汁里加上一些石灰。石灰跟甘蔗汁里的酸性成分化合,变成一种绿色的浮渣。这层浮渣要去掉。②3.剩下的就是一种清澈的黄色糖浆,再把这些糖浆煮一遍,最后大多数水分都变成蒸汽飞走了,留下一种粘稠的棕色液体,是糖和“糖蜜”

(molasses)的混合物。③4.再把这种液体放在大桶里。大桶底部满是小洞,糖蜜就从这些小洞流走,余下的是一种暗灰色的、有粘性的粉末,叫做“粗糖”(raw sugar),这种粗糖盛进糖桶(hogshead)里,然后就用船运往大不列颠了。④5.这种粗糖刚运来的时候,看上去脏兮兮的,你肯定不喜欢吃。要把这种粗糖变得又纯又干净,非要精加工不可。这种精加工大部分是在大城市进行的,比如布里斯托尔(Bristol)、利物浦(Liverpool)、伦敦(London)、格拉斯哥(Glasgow)。

6.首先把粗糖溶解在水里,进行严格的过滤,把糖水滤清。然后再把糖水放在大型的平底锅里煮,直到差不多所有的水都变成蒸汽消失。⑤7.然后把粘稠的糖浆,倒进圆锥形的模具里冷却。完全冷却以后,糖就变成了细小的白色固体,叫做“晶体”(crystal),把糖从模具里倒出来,糖的形状就变成了高高的圆锥形(sugar-loaf)。食品商把这些大糖块切成小块儿,当做“方糖”来出售。⑥8.用甜菜根的汁液制糖,跟用甘蔗制糖,方式差不多完全一样。不过,甘蔗茎是要在滚筒之间碾碎的,甜菜根并不用滚筒碾碎,而是切成薄片,浸在水里,把汁液弄出来,或者叫“提取”(extract)出来。⑦9.小朋友知道,糖可以用来做果酱、蛋糕、油酥糕点,做所有种类的甜食,还可以用来给茶和咖啡加上甜味。⑧10.只是在最近,糖的价钱才变得便宜起来,人人都可以买到足够的糖了。大约在100年以前,英国人还不怎么吃糖,而是用蜂蜜来给食物加甜味。⑨译注①为了保证甘蔗质量,甘蔗从收获到加工的时间不能超过两天。这种用滚筒加工甘蔗小段的工艺,大概相当于现代工艺的第一道工序“提汁”,带有铁滚筒的机器叫做“压榨机”,滚筒叫“辊”。现代除了压榨法之外,还有“渗出法”。咱们在这么多篇课文里都见到了蒸汽机的影子,可见当时蒸汽机的应用有多么广了。

②这大概相当于第二道工序“提纯”,也叫“清净”,是为了除去混合汁中的各种非糖物质。石灰叫做“提纯剂”,除了石灰法之外,还有“亚硫酸法”和“碳酸法”。

③这大概相当于第三道工序“蒸发”。“提纯”后的糖浆含水量太高,因此要用蒸发来提高清净后的糖汁浓度。现代煮糖浆的工具叫做“真空蒸发器”。“糖蜜”的具体成分,随甘蔗品种和加工方法不同而不同,但主要是蔗糖、还原糖等等,可以用来做酒精原料。

④这大概相当于第四道工序“结晶”、第五道工序“分蜜”合在一起。“结晶”是用密闭的煎糖罐,让“蒸发”之后的糖浆到达“饱和”状态,也就是让糖浆里的水分,再也溶解不了那么多糖;这样,固体的糖就变成晶体,从水分中脱身了,称为“糖膏”。但糖膏依然是糖和糖蜜的混合物,需要用“离心机”来把糖和糖蜜分开。这种“大桶”可能是离心机应用之前的设备。其实,离心机早在1852年就开始应用了。

⑤现代的精加工步骤包括硫熏、过滤、清洗、干燥等等。

⑥直到19世纪晚期,工业上才开始广泛生产颗粒状的砂糖,不再生产圆锥糖块了。

⑦这个步骤在现代工艺里的名称跟甘蔗加工一样,也叫“提汁”。

⑧太多的糖对人体有害,现在为了健康原因,也有很多甜食用的是糖醇、甜菊糖甙等等甜味剂;但是各有各的缺点。总之,吃糖要有节制。

⑨除了蔗糖之外,现在人们常吃的糖还有前面提到的葡萄糖、麦芽糖,以及果糖、果葡糖浆等等。历史上导致英国人吃糖量增加的原因是什么呢?原因之一,竟然是前面课文里提到的茶!早期引进英国的茶,味道苦涩,喝了它还容易饥饿,所以当时只有贵族喝茶。但是大约在1750年之后,人们学会了在茶里加糖,茶就大受平民百姓的欢迎了。到了1850年左右,茶已经成了英国平民的必需品。也就是在这100年中,糖打败了蜂蜜,之后再也没有失去过这个地位。原因之二,西欧各国在18世纪都拼命发展本国的蔗糖产业,不仅增加了甘蔗制糖的生产,还大力开发甜菜制糖业。第一次工业革命的兴起,更是让蔗糖的生产插上了科学技术的翅膀。这是糖价下降的外部原因。今天,世界每一个角落都可以见到多种多样的糖果,这是我们童年和整个人生最精彩的回忆之一。现在我们知道了,它们从自然界来到我们面前,经历了相当不平凡的旅程。而在它们背后,居然有着一整部人类文明和科技的发展史,多么神奇啊!

THE SAUCY SPARROW