The "brown stuff" on the apple

Why the apple turned to brown colour?

We always notice that when we peel the apple or cut it into few slices, the apple turned to brown colour. We know that when the apple after being cut became brown colour is because the apple is exposed to the air.

What is the main factor that cause the apple become brown colour after being exposed to the air? Actually, when the flesh of the apple being oxidized in the air, the process is called oxidation. The oxidation of an apple is very similar to the rusting of iron with air. In the oxidation process, the oxygen acts as oxidizing agent.

Besides that, there is a specific enzyme that casues the brown colour appear on the apple which is called polyphenol oxidase (PPO). This enzyme catalyse the o-hydroxylation of monophenols to o-diphenols. PPO enzymes can also catalysed oxidation of o-diphenol to produce o-quinone.

This enzyme can be found in many foods such as breads, chapattis, noodles and so forth. When the cell is broken, the enzyme is released which then reacts with the oxygen in the air and a layer is formed on the outside.

The diagram above has shown the chemical reaction that occurs. In this diagram, we can see that the monophenol reacts with the oxygen in the air, which creates the diphenol. When this chemical reaction is complete, the complex brown polymers are left. So, we can see the "brown stuff" on apple when an apple skin is pierced. The o-quinone reduced the diphenol which in turn is the molecule that is being oxidized. Thus, when an apple is turning brown, actually is the small molecules in the cells are reacting with the oxgen in the air. As a result, a layer of the brwon stuff is forming on the top. But, we no need to worry because it does no make the apple harmful to eat. If you don't want your apple turns to brown colour, what can you do is soak your apple which has been cutting in to the salt water. This can prevent the apple turn to brown colour.

Drug-Caffeine

Caffeine is a common type of drugs which is used to increase alertness and also can decrease fatigue. The most common source of the caffeine is coffee. Beside coffee, there are still many drinks contain caffeine such as tea, soft drinks(pepsi, coca-cola) , chocolate and so forth.

Do you know that a can of cola contains around 35mg of caffeine, a cup of instant coffee contains around 65mg of caffeine and Red Bull had 80mg of caffeine? What are the side effects of taking caffeine?I'll discuss it later.
Now, let us to know more about the formula of the caffeine and its properties.

Caffeine molecular structure

Caffeine is also known as mateine, guaranine, and methyltheobromine. Caffeine is an alkaloid of the methylxanthine family. Its chemical formula is C8H10N4O2.Pure caffeine occurs as odourless, white, fleecy masses, glistening needles or powder. Sometimes caffeine is called theine when it is found in tea . Caffeine is usually produced by the plants which are coffee beans, guarana and tea.

Caffeine is an addictive stimulant. It can stimulate our heart rate,nervous system and also respiration.Besides. caffeine is also considered as a diuretic. Too much of the caffeine may cause the caffeine intoxication. The sign of this disorder are restlessness, nervousness, excitement, insomnia , flushed face, gastrointestinal disturbance and muscle twitching. The following effects are caused by the over use of the caffeine:

1. blood pressure increased

2. urine production increased

3. constricting of the blood vessel

4. stomach acid increased

5. the quality of sleep is affected

6. accelerate bone lose and cause osteoporosis

7. headaches

8. the level of the neurotransmitter dopamine is increased

However, caffeine can be both beneficial and harmful to us. Many of the headaches medicine contain a small amout of the caffeine because it is believed that can be treat the headaches. Caffeine can help the body absorb the headaches medications more quickly so that the painful of the sufferer can be relieved more effective. For example:

a) Aspirin-Free Excedrin Caplets contain 65 mg of caffeine.

b) Pain Reliever Tablets contain 65 mg of caffeine.

c) Anacin Maximum Strength contains 32 mg of caffeine.

d)Excedrin Caplets contain 65 mg of caffeine.

Caffeine can treat headaches and it can also cause someone headaches if taking too much caffeine. Thus, don't addicted to the caffeine. It is harmful to your health!!!