Why the food can last for so long~Huh?

Well, after watching this video. There is a question come out in the mind, why is it the french-fries still in a good shape for almost 10 weeks but all the other burgers went rotten. As we know, it is because of the chemical substances that present in the french-fries that prevent it from rotten, which is the preservative. Preservative is a substance that have been synthesized and add into products like foods, paints or even cosmetics to avoid the decomposition of any microorganisms or avoid any unwanted chemical changes.

Although these preservatives help us a lot in storing food for long periods of time, but somehow it still cost us a lot health problem if we taken in more than the prescribed limits.  “In a study conducted by Southhampton University in 2008, researchers confirmed that children who regularly eat certain preservatives and additives are more at risk for attention disorders such as hyperactivity and lack of impulse control.”

Sources : http://www.ehow.com/list_7377545_sort-preservatives-mcdonalds-food_.html

Let’s see what are those common preservatives that can be
found around us :

BHA (butylated hydroxyanisole) - C₁₁H₁₆O₂

An antioxidant. This food preservative is used to preserve the fresh pork and pork sausages, potato chips, instant teas, cake mixes and many more. In the state of California, they have listed it as a carcinogens  and expected to cause the live diseases and cancer.

Benzoates – C₆H₅COO^-

This food preservative is used in fruit juices, tea, coffee etc. It have been banned in Russia due to its role in triggering allergies, asthma and skin rashes. It is considered to cause the brain damage too.

Sodium Nitrate / Sodium Nitrite – NaNO₃ / NaNO₂

This food preservative is used in meats and fish. It will cause a human carcinogen which includes gastric cancer, oesophageal cancer and colon cancer etc. It is known that the sodium nitrite, sodium nitrate will forms nitrosamines in cured meats which will cause DNA damage and increased cellular degeneration.

Sulfite -  (SO₃)^2-

It can be found from all the wines because it is used in winemaking. Sulfites are often used as preservatives in dried fruits, radish, and dried potato products. People who are sensitive to sulfite will have breathing problem after consuming the food that was containing it. Sulfites are also known to destroy vitamin B₁.

Yucks~ your clothes are dirty? What to do?

There are so many branded detergent in the store but how do we determine which brand are the most effective brand?

Chlorine is added to the detergent to act as bleaching agent.  Chlorine able to displace iodine as the chlorine is a stronger oxidising agent compare to iodine.  So, we can use iodine to titrate with known concentration of sodium thiosulphate to determine the concentration of the’ free chlorine’ in the detergent  in order to compare which work the most effective. The more the concentrate of ‘free chlorine’, the more effective the detergent works.

How detergent work?

We have to understand the structure of the detergent molecule in order to know how the detergent works. The detergent molecule consists of two parts hydrophilic head and hydrophobic tail. Hydrophilic head is made up of sulphonate group which will attract the water molecule to be bind with it as it is polar. While, the tail is made up of a long hydrophobic hydrogen carbon tail.

In water, the hydrophilic head which is negatively charge will dissolve in water, as the water is positively charge. The hydrophobic tail will dissolve on the dirt layer. So, when the water is stir the grease will lift off from the surface. The dirt is emulsify after being lift off from the surface by the surfactant. The dirt then will be breaks into small pieces and wash away with water. They will not clump back into large molecule because each of the small molecule are carrying the same charge, negative charge they will repeal each other. 

Do you know? 

There are two types of water soft and hard water. Hard water contain high amount of mineral with it especially with Mg²⁺and Ca²⁺ ions. While the soft water is free of any minerals. Detergent is effective in both soft and hard water as it do not form scum with Mg²⁺and Ca²⁺  ions.