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(单词翻译:双击或拖选)
It's pretty easy to guess what most of your food is made of. The meat in your hamburger probably came from a cow, the bun was made from grain, the ketchup1 from tomatoes, and so on. There is one kind of food, however, that might have you guessing animal, vegetable or mineral for the whole meal. But no more, since we'll learn about Jello2 on today's Moment of Science. Jello is a trademark3 name for gelatin, a food that people have enjoyed for generations. To answer the question animal, vegetable, or mineral: gelatin is an animal product. It is prepared by soaking the bones, skin, or connective tissue from pigs or cows in a bath of mild hydrochloric acid solution. After this, the animal products are heated in distilled4 water for many hours, and finally boiled. The fluid that collects from this process is drawn5 off. What's left is dried, and ground into a fine, pale yellow powder. This is unflavored gelatin, the basis of all gelatin salads, desserts, and drinks. Gelatin is valuable as a food because it is pure protein and it is easy to digest. A gelatin made from vegetable protein, called agar-agar, is made for vegetarians6. When powdered gelatin is stirred into hot water and then chilled, it forms the jiggly, gelled product that we are most familiar with. This gelled product is not strictly7 a solid or a liquid. Technically8 it's a colloid9: a liquid suspended in a solid framework. As the hot mixture cools off, the long strands10 of animal protein lock together into a solid framework, trapping tiny droplets11 of liquid water in the process. It's these droplets of water, trapped in a mesh12 of animal protein, that hold all the coloring and flavoring in your favorite gelatin dessert.
1 ketchup | |
n.蕃茄酱,蕃茄沙司 | |
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2 jello | |
n.凝胶物,果冻 | |
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3 trademark | |
n.商标;特征;vt.注册的…商标 | |
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4 distilled | |
adj.由蒸馏得来的v.蒸馏( distil的过去式和过去分词 );从…提取精华 | |
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5 drawn | |
v.拖,拉,拔出;adj.憔悴的,紧张的 | |
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6 vegetarians | |
n.吃素的人( vegetarian的名词复数 );素食者;素食主义者;食草动物 | |
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7 strictly | |
adv.严厉地,严格地;严密地 | |
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8 technically | |
adv.专门地,技术上地 | |
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9 colloid | |
n.胶体;adj.胶体的,胶质的 | |
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10 strands | |
n.(线、绳、金属线、毛发等的)股( strand的名词复数 );缕;海洋、湖或河的)岸;(观点、计划、故事等的)部份v.使滞留,使搁浅( strand的第三人称单数 ) | |
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11 droplets | |
n.小滴( droplet的名词复数 ) | |
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12 mesh | |
n.网孔,网丝,陷阱;vt.以网捕捉,啮合,匹配;vi.适合; [计算机]网络 | |
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