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VOA慢速英语2014 巧克力:食物中的上帝

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Chocolate: The 'Food of the Gods' 巧克力:食物中的上帝

From VOA Learning English, this is Science in the News.  

I’m Anna Matteo.

And I’m Christopher Cruise. 

Today on the program, we explore the history of chocolate -- a favorite food for many people. Researchers have known for some time that chocolate is good for the heart. We will report on a study that shows why this is so. We also tell you about the health effects of dark chocolate. 

The Tasty History of Chocolate

The history of chocolate begins with a plant whose scientific name -- Theobroma cacao -- means “food of the gods.” For centuries, people have been enjoying the rich flavor of chocolate, a product made from this plant.

Historians believe the Mayan people of Central America first learned to farm cacao plants around 2,000 years ago. The Maya took the cacao trees from the rainforests and grew them around their homes. They cooked the cacao seeds, then crushed them into a soft paste. They mixed the paste with water and flavorful spices to make an unsweetened chocolate drink.

Cacao and chocolate were an important part of Maya culture. There are often images of cacao plants on Maya buildings and art objects. Ruling families drank chocolate at ceremonies. And, even poorer members of Mayan society could enjoy the drink once in a while. Historians believe that cacao seeds were also used in marriage ceremonies as a sign of the union between a husband and wife.

The Aztec culture in current-day Mexico also prized chocolate. But the cacao plant could not grow in the area where the Aztecs lived. So they traded to get cacao. They even used cacao seeds as a form of money to pay taxes or give as offerings to the gods.

Only the very wealthy people in Aztec societies could afford to drink chocolate because cacao was so valuable. The Aztec ruler Montezuma was believed to have drunk 50 cups of chocolate every day.

Some experts believe the word for chocolate came from the Aztec word “xocolatl,” which means “bitter water” in the Nahuatl language. Others believe the word “chocolate” was created by combining Mayan and Nahuatl words.

The explorer Christopher Columbus brought cacao seeds to Spain after his trip to Central America in 1502. But it was the Spanish explorer Hernando Cortes who understood that chocolate could be a valuable investment. In 1519, Cortes arrived in Mexico. He believed the chocolate drink would become popular with Spaniards. After the Spanish soldiers defeated the Aztec empire, they were able to seize the supplies of cacao and send them home. Spain later began planting cacao in its colonies in the Americas in order to supply the large demand for chocolate.

The wealthy people of Spain first enjoyed a sweetened version of the chocolate drink. Later, the popularity of the drink spread throughout Europe. The English, Dutch and French began to plant cacao trees in their own colonies. Until the 18th century, only wealthy people could afford to drink chocolate. During the period known as the Industrial Revolution, new technologies helped make chocolate less costly1 to produce.

Farmers grow cacao trees in many countries in Africa, Central and South America. The trees grow in the shady areas of rainforests near the Earth’s Equator. But these trees can be difficult to grow.

They require an exact amount of water, warmth, soil and protection. After about five years, cacao trees start producing large fruits called "pods," which grow near the trunk of the tree. The seeds inside this pod are harvested to make chocolate.

Growing cacao is very hard work for farmers. They sell their harvest on a futures2 market. This means that economic conditions beyond their control can affect the amount of money they will earn.

Today, chocolate industry officials, activists3, and scientists are working with farmers. They are trying to make sure that cacao can be grown in a way that is fair to the farmers and safe for the environment.

To become chocolate, cacao seeds go through a long production process in a factory. Workers must sort, clean and cook the seeds. Then they break off the covering of the seeds so that only the inside fruit -- or nibs4 -- remain. Workers crush the nibs into a soft substance called chocolate liquor. This gets separated into cacao solids and a fat called cocoa butter.

Chocolate makers5 have their own special recipes in which they combine chocolate liquor with exact amounts of sugar, milk and cocoa fat. They finely crush this “crumb” mixture so it is smooth. The mixture then goes through two more processes before it is shaped into a mold form.

Chocolate making is a big business. Each year, the market value of the cacao crop around the world is more than five billion dollars. Chocolate is especially popular in Europe and the United States. Americans eat an average of more than five kilograms of chocolate per person every year. Specialty6 shops that sell costly chocolates are also very popular. Many offer chocolate lovers the chance to taste chocolates grown in different areas of the world.

Dark Chocolate and Heart Health

Researchers have known that chocolate -- especially dark chocolate -- is good for the heart. Now, they know why. Besides tasting good, researchers have found that dark chocolate protects against heart disease in two ways: it returns movement to hardening arteries7. It also keeps white blood cells from gathering8 on blood vessel9 walls. Both of these conditions can lead to plaque10 formation. Plaque can block the flow of blood, causing heart disease.

Researchers from the Netherlands reported the findings. The Dutch researchers studied 44 middle-aged11 men who were considered overweight. The men ate 70 grams of both dark and milk chocolate every day over two periods of four weeks.

The heart-healthy substance in chocolate is an organic substance called flavanol. Flavanols are also found in vegetables, fruits and green tea.

Gerald Weissmann is with the FASEB Journal, which published the study findings earlier this year. He says the researchers found that there is something about the flavanols in dark chocolate that makes people like it more than milk chocolate.

“In this controlled study -- the first time it’s ever been done -- they gave the same amount of flavanol in dark chocolate and regular chocolate. And lo and behold12, the men didn’t have different amounts of flavanols in the diet. But they ate more of the dark chocolate one because they liked it better.”

Mr. Weissman says researchers asked the men in the study to talk about the smell and taste of dark chocolate.  

“So, the taste component13 or psychological component of dark chocolate improved, number one, the elasticity14 and response of the arteries to blood flow, number two, the way that neutrophils -- white cells -- stick to the lining15 of blood vessels16 and number three, markers of inflammation.”

And knowing it was good for the heart seemed to make the men feel less guilty about eating it.

Researchers may someday develop a treatment that has the same health benefits as dark chocolate. But even if they do, we are sure that eating a piece of dark chocolate will still be more fun.

Scientists to Study Health Benefits of Chocolate 

Dark chocolate has been shown to help prevent heart disease. But eating too much of it may cause people to gain weight. Now, scientists are looking for a way to put dark chocolate’s helpful ingredients -- or parts -- into pills. That way, we can get the benefits of dark chocolate, but not the weight gain.  

Cacao has flavanols that may help reduce the risk of heart attack or stroke. These chemicals may lower blood pressure and cholesterol17 levels, and improve the body’s use of insulin. Insulin helps control the amount of glucose18 or sugar in the blood.

Steve Koumanelis is a chocolatier. He makes and sells chocolate treats in Washington, D.C. He says dark chocolate is an increasingly popular product.

“A lot of people are gravitating towards dark chocolate because they just decide they love it, and they also have been reading all about the health benefits of dark chocolate.”

But those health benefits have yet to be confirmed in studies involving large numbers of people. Also, during the manufacture of chocolate, many flavanoids are destroyed, while sugar and fats are added to make the chocolate taste better. 

Scientists want to learn the benefits of flavanols before they are changed in the manufacturing process. They have announced plans for a four-year-long study of 18,000 adults. The subjects will take small amounts of pure cacao flavanols. The study is believed to be the largest of its kind. 

Jo-Ann Manson works at Brigham and Women’s Hospital in Boston, Massachusetts. She is the lead researcher in the study.

“This capsule of cocoa flavanols will avoid having the calories and the sugar and the saturated19 fat found in chocolate.”

And the flavanols will not have any taste.

The subjects in the new study are to be separated into two groups.  Members of one group will take pills containing flavanols. The other group will take “placebo” pills -- substances that do not have anything in them, other than, perhaps, sugar.

Whatever the result of the study, chocolatier Steve Koumanelis is not worried about his business.

“People like the experience of actually biting into a piece of chocolate, whatever their favorites are.”

The flavanol benefits test is just starting. For now, people will have to get their flavanols the tasty way -- by eating dark chocolate!

This Science in the News was written by Dana Demange and Christopher Cruise, who also produced the program.  


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点击收听单词发音收听单词发音  

1 costly 7zXxh     
adj.昂贵的,价值高的,豪华的
参考例句:
  • It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
  • This dictionary is very useful,only it is a bit costly.这本词典很有用,左不过贵了些。
2 futures Isdz1Q     
n.期货,期货交易
参考例句:
  • He continued his operations in cotton futures.他继续进行棉花期货交易。
  • Cotton futures are selling at high prices.棉花期货交易的卖价是很高的。
3 activists 90fd83cc3f53a40df93866d9c91bcca4     
n.(政治活动的)积极分子,活动家( activist的名词复数 )
参考例句:
  • His research work was attacked by animal rights activists . 他的研究受到了动物权益维护者的抨击。
  • Party activists with lower middle class pedigrees are numerous. 党的激进分子中有很多出身于中产阶级下层。 来自《简明英汉词典》
4 nibs 4e6b6891fc0ecd3914703a92810bbcb3     
上司,大人物; 钢笔尖,鹅毛管笔笔尖( nib的名词复数 ); 可可豆的碎粒; 小瑕疵
参考例句:
  • They were careful not to offend his nibs. 他们小心翼翼,不敢冒犯这位大人。
  • Please tell his nibs that we'd like his help with the washing-up! 请转告那位大人,我们想请他帮助刷锅洗碗!
5 makers 22a4efff03ac42c1785d09a48313d352     
n.制造者,制造商(maker的复数形式)
参考例句:
  • The makers of the product assured us that there had been no sacrifice of quality. 这一产品的制造商向我们保证说他们没有牺牲质量。
  • The makers are about to launch out a new product. 制造商们马上要生产一种新产品。 来自《简明英汉词典》
6 specialty SrGy7     
n.(speciality)特性,特质;专业,专长
参考例句:
  • Shell carvings are a specialty of the town.贝雕是该城的特产。
  • His specialty is English literature.他的专业是英国文学。
7 arteries 821b60db0d5e4edc87fdf5fc263ba3f5     
n.动脉( artery的名词复数 );干线,要道
参考例句:
  • Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
  • This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》
8 gathering ChmxZ     
n.集会,聚会,聚集
参考例句:
  • He called on Mr. White to speak at the gathering.他请怀特先生在集会上讲话。
  • He is on the wing gathering material for his novels.他正忙于为他的小说收集资料。
9 vessel 4L1zi     
n.船舶;容器,器皿;管,导管,血管
参考例句:
  • The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
  • You should put the water into a vessel.你应该把水装入容器中。
10 plaque v25zB     
n.饰板,匾,(医)血小板
参考例句:
  • There is a commemorative plaque to the artist in the village hall.村公所里有一块纪念该艺术家的牌匾。
  • Some Latin words were engraved on the plaque. 牌匾上刻着些拉丁文。
11 middle-aged UopzSS     
adj.中年的
参考例句:
  • I noticed two middle-aged passengers.我注意到两个中年乘客。
  • The new skin balm was welcome by middle-aged women.这种新护肤香膏受到了中年妇女的欢迎。
12 behold jQKy9     
v.看,注视,看到
参考例句:
  • The industry of these little ants is wonderful to behold.这些小蚂蚁辛勤劳动的样子看上去真令人惊叹。
  • The sunrise at the seaside was quite a sight to behold.海滨日出真是个奇景。
13 component epSzv     
n.组成部分,成分,元件;adj.组成的,合成的
参考例句:
  • Each component is carefully checked before assembly.每个零件在装配前都经过仔细检查。
  • Blade and handle are the component parts of a knife.刀身和刀柄是一把刀的组成部分。
14 elasticity 8jlzp     
n.弹性,伸缩力
参考例句:
  • The skin eventually loses its elasticity.皮肤最终会失去弹性。
  • Every sort of spring has a definite elasticity.每一种弹簧都有一定的弹性。
15 lining kpgzTO     
n.衬里,衬料
参考例句:
  • The lining of my coat is torn.我的外套衬里破了。
  • Moss makes an attractive lining to wire baskets.用苔藓垫在铁丝篮里很漂亮。
16 vessels fc9307c2593b522954eadb3ee6c57480     
n.血管( vessel的名词复数 );船;容器;(具有特殊品质或接受特殊品质的)人
参考例句:
  • The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
  • All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》
17 cholesterol qrzzV     
n.(U)胆固醇
参考例句:
  • There is cholesterol in the cell of body.人体细胞里有胆固醇。
  • They are determining the serum-protein and cholesterol levels.他们正在测定血清蛋白和胆固醇的浓度。
18 glucose Fyiyz     
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。
19 saturated qjEzG3     
a.饱和的,充满的
参考例句:
  • The continuous rain had saturated the soil. 连绵不断的雨把土地淋了个透。
  • a saturated solution of sodium chloride 氯化钠饱和溶液

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