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  3. Barbecuing meat gives it great flavor. This taste, though, comes at a price, since the process creates molecules called polycycl

Barbecuing meat gives it great flavor. This taste, though, comes at a price, since the process creates molecules called polycycl

admin2022-05-13  68
问题     Barbecuing meat gives it great flavor. This taste, though, comes at a price, since the process creates molecules called polycyclic aromatic hydrocarbons (PAHs) which damage DNA and thus increase the eater’s chances of developing cancer. For those who think barbecues one of summer’s great delights, that is a shame. But a group of researchers led by Isabel Ferreira of the University of Porto, in Portugal, think they have found a way around the problem. When barbecuing meat, they suggest, you should add beer.
    This welcome advice was the result of some serious experiments, as Dr Ferreira explains in a paper in the Journal of Agricultural and Food Chemistry. The PAHs created by barbecuing form from molecules called free radicals which, in turn, form from fat and protein in the intense heat of this type of cooking. One way of stopping PAH-formation, then, might be to use chemicals called antioxidants that clear away free radicals. And beer is rich in these, in the shape of melanoidins, which form when barley is roasted. So Dr Ferreira and her colleagues prepared some beer marinades, bought some steaks and headed for the pan.
    One of their marinades was based on Pilsner, a pale beer. A second was based on a black beer. Since black beers have more melanoidins than light beers—as the name suggests, they give it color—Dr Ferreira’s hypothesis was that steaks immersed in the black-beer marinade would form fewer PAHs than those immersed in the light-beer marinade, which would, in turn, form fewer than steaks left unmarinated.
    And so it proved. When cooked, unmarinated steaks had an average of 21 nanograms of PAHs per gram of barbecued meat. Those marinated in Pilsner averaged 18 nanograms. Those marinated in black beer averaged only 10 nanograms. Tasty and healthy too, then. Just what the doctor ordered.
According to the last paragraph, which steak is the most healthy?
选项 A、Steak in black beer.
B、Unmarinated steak.
C、Steak in pale beer.
D、Well-done steak.
答案A
解析 细节题。定位到最后一段。该段提到PAHs一词，而该词首次出现在第一段：(PAHs) which damage DNA and thus increase the eater’s chances of developing cancer. 该句明确指出：PAHs可以破坏DNA，提高患癌几率，由此可见PAHs应该是一种致癌物质。而该段提到这种致癌物质含量最少的(即题目问的最健康的) 是those(steaks) marinated in black beer“那些用黑啤腌制过的牛排”，A项正确。故本题答案为A项。
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