首页
登录
职称英语
Natural flavorings and fragrances are often costly and limited in supply. Fo
Natural flavorings and fragrances are often costly and limited in supply. Fo
游客
2025-02-03
23
管理
问题
Natural flavorings and fragrances are often costly and limited in supply. For example, the vital ingredient in a rose fragrance is extracted from natural rose oil at a cost of thousands of dollars a pound; an identical synthetic substance can be made for 1% of this cost. Since the early twentieth century, success in reproducing these substances has created a new industry that today produces hundreds of artificial flavors and fragrances.
Some natural fragrances are easily synthesized; these include vanillin, the aromatic ingredient in vanilla, and benzaldehyde, the aromatic ingredient in wild cherries. Other fragrances, however, have dozens, even hundreds of components. Only recently has it been possible to separate and identit3, these ingredients by the use of gas chromatography and spectroscopy. Once the chemical identity is known, it is often possible to synthesize them. Nevertheless, some complex substances, such as the aroma of fresh coffee, have still not been duplicated satisfactorily.
Many of the chemical compounds making up these synthetics are identical to those found in nature, and are as harmless or harmful as the natural substances. New products must be tested for safety, and when used in food, must be approved by the U.S. Food and Drug Administration.
The availability of synthetic flavors and fragrances has made possible a large variety of products, from inexpensive beverages to perfumed soap to used cars with applied "new car odor." [br] Which of the following is the best title for tile passage?
选项
A、How to Synthesize Fragrances
B、Synthetic Substances Are Easy to Make
C、Natural Flavorings and Fragrances
D、Synthetic Flavors and Fragrances
答案
D
解析
阅读全文可知本文是围绕天然调味品和香料供应有限且价格不菲(见第一段第一句),后有了人工合成品替代(尽管有些合成容易,有些困难),使大量生产成为可能:其中主要部分谈的是人工合成品(调味品和香料):因此选项D为答案。
转载请注明原文地址:http://tihaiku.com/zcyy/3940571.html
相关试题推荐
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Thefirstrecordeduseofnaturalgastolightstreetlampsitwasinthetowno
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
随机试题
Tom______betterthantoaskDickforhelp.A、shallknowB、shouldn’tknowC、haskn
WhatcanweknowfromthenewsaboutMartinKippenberger?[br][originaltext]
民间艺人folkartist;folkartisan
Whywedreamstillremainsoneofthegreatmysteries.Butinanswertothe
有一蚂蚁P从菱形ABCD的顶点A出发,沿以A→D→B以1厘米每秒的速度匀速运动到
在HTML中,用于输出“>”符号应使用()。A.gt B.\gt C.&
下列不属于证券产品选择目标的是()。A.取得收益 B.提高风险 C.
如果在午休时间,有个幼儿大吵大闹,你会怎么办?
下列哪项不是医疗事故的特征A.责任主体是取得执业资格的医务人员 B.主观上存在
关于建筑分类下列说法正确的是()。A.某商场共五层,层高5m,层面积120
最新回复
(
0
)