双语化学：有机化合物
徐州市第五中学 葛健华
我们每天都要摄入各种食物，如大米、面粉、食用油、蛋、肉、鱼、
牛奶、青菜和水果等。这些食物的主要成分是什么?它们是不是有
机化合物?
大米、面粉的主要成分是淀粉，
食用油中含有油脂，鱼、肉、牛奶中含
有丰富的蛋白质，青菜、水果中含有
维生素，青菜中还含有纤维素。淀
粉、油脂、蛋白质和维生素是食物中
含有的重要有机物，是食物中的主要
营养成分。
各种各样的食品
一些食品的营养成分
(每
100g
食品中营养成分的含量)
| |
蛋白质／g
|
脂肪／g
|
糖类／g
|
矿物质／mg
|
维生素B1
／mg
|
维生素C
／mg
|
| 钙
|
磷
|
铁
|
| 大米
|
6.7
|
0.9
|
78
|
7
|
136
|
—
|
0.19
|
0.05
|
| 番茄
|
0.6
|
0.3
|
2
|
8
|
37
|
0.4
|
0.03
|
11
|
| 肥猪肉
|
2.2
|
90.8
|
0.8
|
1
|
26
|
0.4
|
|
|
| 鲫鱼
|
13.0
|
1.1
|
0.1
|
54
|
203
|
2.5
|
0.06
|
|
| 牛奶
|
3.1
|
3.5
|
6
|
120
|
90
|
0.1
|
0.04
|
1
|
| 鸡蛋
|
14.8
|
11.6
|
0.5
|
55
|
210.207
|
0.16
|
|
|
除淀粉、纤维素外，人们的许多食物中还含有油脂、蛋白质和维生素。
它们也都是有机化合物。
牛油、猪油、奶油、花生油、豆油、菜油和椰子油等都属于油脂，也是重要的
营养物质。牛油、猪油等来自动物体的脂肪层，是动物性油脂，在常温下通常呈
固态，叫做脂。植物种子里
也含有丰富的油脂，如花生
油、豆油和菜籽油等植物性
油脂，在常温通常呈液态，
叫做油。
各种油脂也都是由碳、
氢、氧三种元素组成的。
油脂的分子组成、结构、
性质与淀粉、纤维素不同。 富含油脂的食物
例如，油脂不溶于水，易溶于汽油等有机溶剂，密度比水小。各种油脂的相对
分子质量只有数百左右，不是高分子化合物。
食物中不同种类的油脂组成、性质不完全相同，但它们在人体内消化，发生
氧化分解，都能释放出热量。人体内的脂肪储备着丰富的热能，一个人如果活动
量小，热量消耗就少，体内积累的脂肪就多。如果摄人的碳水化合物过多，剩余
部分也会转化为脂肪。如果摄入食物提供的热量不足，体内的脂肪就会被消耗，
以补充人体需要的能量。
蛋白质是构成人体细胞的基础物质。没有蛋白质就没有生命。婴幼儿和青少
年在成长过程中要摄人较多富含蛋白质的食物。成人也要通过饮食补充蛋白质。
富含蛋白质的食物
蛋白质中一定含有碳、氢、氧、氮元素，有
些蛋白质还含有硫等元素。蛋白质和淀粉、
纤维素一样也是有机高分子化合物。蛋白质
种类繁多，结构十分复杂。在无数科学家艰
苦卓绝的研究下，今天人们已经对蛋白质的
结构有了深入的认识，还用人工方法合成了
一些种类的蛋白质。我国于1965年在世界
上第一次用人工方法合成的结晶牛胰岛素，
就是一种有生命活力的蛋白质。
食物中的蛋白质在胃、肠中的酶及体内
水的作用下，逐步分解，生成可被小肠吸收的
小分子化合物氨基酸。
某种氨基酸(上)和蛋白质(下)
的分子结构示意图
The organic compounds in food
We take different foods every day, suchas rice, flour, edible oil, eggs, meat, fish, milk, vegetables and fruits. Whatare the main substances of those foods? Are they organic compounds?
Various foods
Main component of rice and flour isstarch. There are lipids in edible oil, vitamins in vegetables and fruits, andcellulose in vegetables. Starch, lipids, protein, and cellulose are importantorganic compounds in food as nourishments.
Nourishments in some foods (nourishmentquantity in each 100g food)
| Protein/g
|
Protein /g
|
Fat/g
|
Carbonhyrate/g
|
Mineral substance/mg
|
Vitamin B1/mg
|
Vitamin C/mg
|
| 钙
|
磷
|
铁
|
| Rice
|
6.7
|
0.9
|
78
|
7
|
136
|
—
|
0.19
|
0.05
|
| Tomato
|
0.6
|
0.3
|
2
|
8
|
37
|
0.4
|
0.03
|
11
|
| Fat pork
|
2.2
|
90.8
|
0.8
|
1
|
26
|
0.4
|
|
|
| Crucian
|
13.0
|
1.1
|
0.1
|
54
|
203
|
2.5
|
0.06
|
|
| Milk
|
3.1
|
3.5
|
6
|
120
|
90
|
0.1
|
0.04
|
1
|
| Egg
|
14.8
|
11.6
|
0.5
|
55
|
210.207
|
0.16
|
|
|
Besides starch and cellulose, there arealso lipids, proteins and vitamins in many foods. They are also organiccompounds.
Butter, lard, cream, peanut oil, beanoil, rape oil and coconut oil are all sorted as lipids. They are also very importantnourishments. Butter and lard come from the fat of animals as animal greases,and appear as solid under normal temperature. There is also rich oil in plantseeds, such as peanut, bean or rapeseed. These oils are plant oils, and appearnormally liquid under normal temperature.
Lipids are comprised by carbon,hydrogen and oxygen elements. The molecule composition, structure andproperties of lipids are different from starch and cellulose. For example,lipids can’t be dissolved into water, but can be in organic dissolvent likegasoline, and its density is smaller than water. The relative molecular mass oflipids is only hundreds, so they are not polymeric compounds.
Fat-rich foods
The compositions and properties ofdifferent lipids in food are quite different, but they can all generate heatduring digestion, oxidization and decomposition in human body. There storesplenty of heat in the fat of human body. If a person take less activities, itwill consume less energy, and then the accumulated fat will increase. If toomuch carbonhydrate is taken, the unconsumed part will be turned into fat. Ifthe energy from taken food is insufficient, the fat in the body will be consumedto supplement the necessary energy for human.
Proteins are the basic substances tocompose human cells. No protein, no life. Infants and teenagers have to takemore foods rich of protein during growth. Adults also have to take proteinsfrom foods.
Foods rich of protein
There must be carbon, hydrogen, oxygenand nitrogen elements in proteins. Some proteins also have sulfur element.Proteins are also organic polymeric compounds, like starch and cellulose.Proteins have many species, and complicated structures. After hard researchesby numerous scientists, the structure of proteins have been understood deeply,and some kinds of proteins can be synthesized artificially. Crystalline bovineinsulin was synthesized artificially by China in 1965, which is the first timeto get protein with life vitality artificially in the world.
The proteins in foods are discomposed graduallyto small molecule compounds of amino acid by enzymes and water in the stomachand the intestines, which can be absorbed by small intestine。
Molecular structure diagram of Some kind of amino acid (up)and protein(down)
本文发表于2015.12《江苏教师》
