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
2025-01-28
18
管理
问题
Natural flavorings and fragrances are often costly and limited in supply. For example, the essential 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]
Were he not
taken good care of, he would not have recovered so quickly.
选项
A、Had he been not
B、Had he not been
C、Had not he been
D、Not had he been
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3932899.html
相关试题推荐
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
Naturalflavoringsandfragrancesareoftencostlyandlimitedinsupply.Fo
With2005fastbecoming"theyearofthenaturaldisaster",itistimetor
With2005fastbecoming"theyearofthenaturaldisaster",itistimetor
With2005fastbecoming"theyearofthenaturaldisaster",itistimetor
With2005fastbecoming"theyearofthenaturaldisaster",itistimetor
With2005fastbecoming"theyearofthenaturaldisaster",itistimetor
随机试题
OurneighborUncleWangisastubbornman.Needlesstosay,wetried______tom
Peoplehavewonderedforalongtimehowtheirpersonalitiesandbehaviorsa
OfalltheemployedworkersintheUnitedStates,12.5millionarepartofa
WheneverIhearaweatherreportdeclaringit’sthehottestJune10onrecor
数据库管理系统是操纵和管理数据库的大型软件,用于建立、使用和维护数据库。以下关于
共用题干 SaunaCeremonialbathinghasexist
下列选项中,关于2020年1—2月份我国房屋施工、新开工、竣工面积中商业
一般来说,不可能作为一国货币政策最终目标的是()A.稳定物价 B.
对于一手个人住房贷款,商业银行最主要的合作单位是()。A.房地产开发商
女性,16岁,满月脸,多血质外貌,向心性肥胖,皮肤紫纹、痤疮。高血压,情绪不稳定
最新回复
(
0
)