英语听力文摘 English Digest 269、蜂蜜-历史悠久的保鲜剂

　　The Oldest Sweetener, the Freshest Bread
蜂蜜成分75％ 以上为糖类。据市场调查，90％ 以上的人都认为蜂蜜与砂糖、异构糖、饴糖、人工甜味剂相比对人体健康更为有益。蜂蜜不仅是天然甜昧剂， 而且述具有其他的特殊功效。如利用蜂蜜的风味，甜昧、抗氧化机能和澄清天然水果汁类的机能，可以开发出多种新产品。
Honey has been around for a very long time.  Cave paintings in Spain from over ten thousand years ago show people harvesting honey.  Today honey is mostly used for its distinctive¹ flavor, but for baking it has another advantage as well: baked goods made with honey take longer to get stale.

　　Honey helps baked goods stay fresh longer because, unlike common table sugar(蔗糖；食糖), honey is made of two so-called “simple” sugars: glucose²(葡萄糖) and fructose(果糖).  Table sugar also has glucose and fructose, but they’re chemically bonded³ together in a double sugar(【生物化学】双糖) called “sucrose(蔗糖).”  Having two single sugars instead of one double sugar means that ounce-for-ounce honey contains more sugar molecules⁵, which is why honey is also a little sweeter than table sugar.
But the reason honey helps keep baked goods fresh has to do with the ability of sugar to attract and hold onto water molecules.  All these sugars are “hygroscopic,” that is they attract and hold onto water, each sugar molecule⁴ holding several water molecules.  By holding onto water, the sugar helps keep moisture from escaping from the food and so keeps it tasting fresher longer.
But when two sugars, like fructose and glucose, bond to each other, they lose some of their ability to bond to water molecules.  And that means your bread or cake will lose water faster.  Honey’s attraction to water is also why candy made from honey tends to get stickier than candy made from sucrose, or table sugar.
Commercial bakeries use chemicals like Polysorbate(聚山梨醇酯) to keep baked goods fresh, but with honey you can do it naturally. Incidentally, if you’re worried that honey will make your cake too heavy, try beating the honey until it’s frothy before adding the other ingredients.

1 distinctive   

adj.特别的，有特色的，与众不同的

参考例句：

• She has a very distinctive way of walking.她走路的样子与别人很不相同。
• This bird has several distinctive features.这个鸟具有几种突出的特征。

2 glucose   

n.葡萄糖

参考例句：

• I gave him an extra dose of glucose to pep him up.我给他多注射了一剂葡萄糖以增强他的活力。
• The doctor injected glucose into his patient's veins.医生将葡萄糖注入病人的静脉。

3 bonded   

n.有担保的，保税的，粘合的

参考例句：

• The whisky was taken to bonded warehouses at Port Dundee.威士忌酒已送到邓迪港的保稅仓库。
• This adhesive must be applied to both surfaces which are to be bonded together.要粘接的两个面都必须涂上这种黏合剂。

4 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

5 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。