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
2024-01-01
21
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 identify 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] From the passage we can learn that ______.
选项
A、natural flavorings and fragrances are not quite dear
B、the limitation of natural flavorings and fragrances is clear
C、the supply of natural flavorings and fragrances is adequate to meet the demand
D、the cost of producing natural flavorings and fragrances is high
答案
D
解析
细节题型。见第一段第一句:Natural flavorings and fragrances are often costly and limited in supply.因此选项D为答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3325552.html
相关试题推荐
Damsarecostly,butoncetheyhavebeenbuilt,______electricityverycheaply.A
Thelimitedgaincouldhardlyserveasarelievingjustificationforthetremend
Norwayis,quitenaturally,payinggreatattentiontodevelopmentsinEuropeand
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
随机试题
[originaltext]W:Welcometoourprogramme,John.M:Thankyou.W:Youhavebeen
发展的实质是( )A.事物的前进上升运动 B.事物数量的增加和减少 C.事
唾液含的消化酶是()。A.淀粉酶 B.蛋白酶 C.ATP酶 D.脂肪酶
公开募集基金合同的内容包括()。 Ⅰ.基金的运作方式 Ⅱ.基金份额赎回
下列关于城市公共交通规划的表述,正确的有( )。A.城市公共交通系统的形式要根
简述在进行德育时贯彻导向性原则的基本要求。
资料:DesktopSupportforPrivateEquityFi
分析论述教学过程中应处理好的几种关系。
一般资料:男,28岁,未婚,公司职员。 求助问题:反复思考毫无意义的问题,伴急
最新回复
(
0
)