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on this Moment of Science Yael and Don discuss what causes the brown spots on bananas. Y: So Don, yesterday I was walking down the produce aisle1 when I saw it--long, ripe,yellow. The perfect banana. It really looked delicious and I had to have it. I took it home and hung it on a banana hanger2. The very next morning, it developed nasty brown spots.
D: And you're wondering what gives.
Y: Right. It was a good banana yesterday. What happened?
D: It's no mystery, Yael. Those spots are a natural part of the ripening4 process. You see, just like all fresh produce, your bananas are alive. They're taking in oxygen to help them convert sugars into energy, and releasing carbon dioxide. This process is called respiration5.
Y: I don't know, Don, this banana looks dead to me.
D: Now, the quicker a fruit or vegetable respires, the quicker it ripens6. For most fruits,the respiration rate slows down after the initial growth stage and the fruit ripens slowly. The growth and ripening process of bananas, however, is different. Although at first the banana's respiration slows down too, when it's ready to ripen3, the banana's pulp7 releases a chemical that increases respiration. This converts the starches8 in the banana to sugars and gives it its fabulous9 taste. And you know how good bananas taste!
Y: Watch it--you're drooling. But what does all this ripening have to do with spots?
D: Well, with all this respiration, the banana eventually processes all the starches available. And that's when it begins to die. Those brown spots are rot and decay.
Y: Poor thing. It just ran out of fuel.
D: Yeah, it's never easy seeing a good banana go bad.
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1 aisle | |
n.(教堂、教室、戏院等里的)过道,通道 | |
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2 hanger | |
n.吊架,吊轴承;挂钩 | |
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3 ripen | |
vt.使成熟;vi.成熟 | |
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4 ripening | |
v.成熟,使熟( ripen的现在分词 );熟化;熟成 | |
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5 respiration | |
n.呼吸作用;一次呼吸;植物光合作用 | |
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6 ripens | |
v.成熟,使熟( ripen的第三人称单数 ) | |
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7 pulp | |
n.果肉,纸浆;v.化成纸浆,除去...果肉,制成纸浆 | |
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8 starches | |
n.淀粉( starch的名词复数 );含淀粉的食物;浆粉v.把(衣服、床单等)浆一浆( starch的第三人称单数 ) | |
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9 fabulous | |
adj.极好的;极为巨大的;寓言中的,传说中的 | |
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