What is the Content of Carbonated Drinks?

            Nowadays, carbonated beverages are very common as we can see it everywhere and I believe every one of you drink it before. Examples of the common carbonated beverages or soft drinks are such as tonic water, coca-cola, pepsi, sprite and others. The ingredients of carbonated beverages are high purity water, sweeteners, acidulants, preservatives, carbon dioxide, flavors, colorants, potassium and sodium.

        Production of carbonated beverages needs a lot of high purity water. The process chlorination in chemical treatment is needed to prevent oxidation and infection of impurities in the water. Lime is added to reduce the alkalinity of water by removing magnesium and calcium bicarbonate. The remains precipitate is then removed by sand filter. The water contaminants normally will be removed by a process called reverse osmosis. Not only that, the tiny macromolecules and microorganisms are removed by the ultrafiltration process using thin and selective membrane. 

          The sweetener used in carbonated drinks can be nutritive or non-nutritive. Sweetener is very important in the production of the beverages as its quality will affect the quality of the end products. Nutritive sweeteners composed of granulated sucrose, invert sugar, dextrose, and high fructose corn syrup. Sucrose C₁₂H₂₂O₁₁ is commonly used as the primary sweetener in the production of carbonated beverages. The sucrose will be hydrolyzed into invert sugar which is composed of fructose C₆H₁₂O₆ and dextrose C₆H₁₂O₆ (C-Glucose). There is only a few of non-nutritive sweeteners such as, aspartame C₁₄H₁₈N₂O₅, saccharin C₇H₅NO₃S and acesulfame in the US. 

          The adding of acidulants causes the carbonated beverages to have a sour taste. It is also functioned as preservative by adjusting the pH value to reduce the microorganisms. Examples of acidulants are phosphoric acid (cola), citric acid (fruit flavors) and ascorbic acid.

           Carbon dioxide plays an important role too as it makes the beverages to have bubbles, fizz, acidic bite and a pungent taste. The carbon dioxide used should be free of impurities so that it will not affect the final product. The concentration of carbon dioxide is depends on the formula of the beverages while the carbonation is depends on the CO₂ pressure and temperature of the mixture. 

 Bubbles can be seen in carbonated beverage

           Flavor is important for any foods and beverages. Most of the carbonated drinks used the natural sources. Examples of flavors are such as caffeine (cola), juice-based (juices), essential oil, alcoholic solution and emulsion.

          Colorants are used to improve the appearance of the carbonated beverages to make it more attractive. There is natural colorants and artificial colorants (caramel). Caramel is colloidal with small ionic charges and normally used in cola and root beer. For some beverages, colorants are added in powder forms.
 

          The essential minerals – potassium and sodium can be found in the carbonated drinks. Potassium originally exists in the water and other ingredients that used to produce beverages. Carbonated drinks consist of very little of sodium and even some of the carbonated drinks do not consist any sodium. 

 Examples of carbonated beverages

 *Here is a video  show us about how to make carbonated drinks at home:

 

Finally, we can also make our carbonated drinks at home!!

Why do we brush teeth with toothpaste?

Tooth is made of enamel, containing hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂. Tooth enamel is the hardest and most highly mineralized substance in the body. This high mineral content gives it strength and hardness, but also brittleness. The happen of tooth decaying process is caused of enamel undergoes demineralization. The combination of mouth bacteria and sugars from foods, snacks, soft drinks, sweets and others can generate lactic acid. The acidic conditions over time in mouth cause the enamel to slowly dissolve, diffuses to Ca²⁺ ions and HPO₄^2- ions. When enamel slowly dissolves, tooth cavities eventually formed and this allows more bacteria invade deeper into the tooth, which assists the tooth decay process. 

The chemical equation is

    Ca₁₀(PO₄)₆(OH)₂  (s) + 8H⁺ (aq)  --> 10 Ca²⁺ (aq) + 6HPO₄²⁺ (aq) +    2H₂O (l)

To prevent tooth decay, we have been doing the prevention way since we were small, which is brushing teeth with toothpaste. By brushing teeth with toothpaste, fluoride, F^- ions are introduced to enamel, replacing hydroxide, OH^- ions in hydroxyapatite and becoming fluorapatite, Ca₁₀(PO₄)₆F₂. Fluoride ions replacing hydroxide ions is more resistant to acid attacks because fluorapatite is a weak base compared to hydroxyapatite.

                So, we should brush our teeth everyday at least twice!! 

*Click here to view a journal abstract from 'British Dental Journal'.  

 

Why did I cry for ALLIUM CEPA?

The common name of Allium Cepa is known as onion, a normal type of vegetable which can be easily found in our daily dishes. The question is, why cutting an onion will make us tear? 

           Onion contains sulphur compounds for their chemical defence mechanism in order to prevent the onion form attacking by pests and insects. The pungent smell released from onion is mainly due to these compounds. The cellular structures of onion are destroyed once we cut it apart, which then resulted the enzyme Alliinase and a class of molecules called amino acid sulfoxides to be released from the broken cells. The amino acid sulfoxides are then broken down by the enzyme Alliinase to to produce sulfenic acids. 1-propenesulfenic acid is a one type of  sulfenic acid formed when the plant cells of onions are damaged. This sulfenic acid is rearranged to form syn-Propanethial-S-oxide by another type of enzyme named lachrymatory factor synthase(LFS). Syn-Propanethial-S-oxide is in gas from and also a type of lachrymatory agent. Lachrymatory agent is a type of chemical which can stimulates the corneal nerves in the eyes cause tearing effect. When the gas diffuses into the air and gets contact with the eyes, the corneal nerves are stimulated and taking actions by carrying out lachrymation. The purpose of this reaction is to clean away the irritants which entered the eyes by tears flowing out from the eyes. 

STOP CRYING for ONION!

           Lachrymation can be restrained by cooling the onion before preparing it for dishes and dipping it into water for a while after peeling off the first layer of it. Why? Cooling the onion will consequently changes the optimum temperature for the enzyme to be active, thus the speed of chemical reactions will slow down. Secondly, dipping the onion into the water after peeling can allow the sulphur compounds to be reacted with the water and thus there is no irritating gases are formed. 

END. 

Hair Bleaching & Hair Colouring

Hair Bleach

Hair bleaching is a process used to turn brunettes into blonds. You didn’t really think that there were that many blonds in the world did you? Hair bleach is a chemical reaction between melanin (the material in hair that gives it color) and hydrogen peroxide.

Bleach is used to lighten hair. The bleach reacts with the melanin in hair, removing the color in an irreversible chemical reaction. The bleach oxidizes the melanin molecule. The melanin is still present, but the oxidized molecule is colorless. However, bleached hair tends to have a pale yellow tint. The yellow color is the natural color of keratin, the structural protein in hair. Also, bleach reacts more readily with the dark eumelanin pigment than with the phaeomelanin, so some gold or red residual color may remain after lightening. Hydrogen peroxide is one of the most common lightening agents. The peroxide is used in an alkaline solution, which opens the hair shaft to allow the peroxide to react with the melanin.


SHOLAR JOURNAL: 
http://webcache.googleusercontent.com/search?q=cache:http://journal.scconline.org/pdf/cc1970/cc021n13/p00875-p00900.pdf

Hair Colors

Hair coloring is a slightly more complicated version of hair bleach. It uses hydrogen peroxide to break down hair’s natural color then the peroxide also oxidizes a polymeric reaction with dye monomers. When the dye polymerizes inside the hair, it creates a color molecule that is too big to easily come back out.   

The outer layer of the hair shaft, its cuticle, must be opened before permanent color can be deposited into the hair. Once the cuticle is open, the dye reacts with the inner portion of the hair, the cortex, to deposit or remove the color. Most permanent hair colors use a two-step process (usually occurring simultaneously) which first removes the original color of the hair and then deposits a new color. It's essentially the same process as lightening, except a colorant is then bonded within the hair shaft. Ammonia is the alkaline chemical that opens the cuticle and allows the hair color to penetrate the cortex of the hair. It also acts as a catalyst when the permanent hair color comes together with the peroxide. Peroxide is used as the developer or oxidizing agent. The developer removes pre-existing color. Peroxide breaks chemical bonds in hair, releasing sulfur, which accounts for the characteristic odor of hair color. As the melanin is decolorized, a new permanent color is bonded to the hair cortex. Various types of alcohols and conditioners may also be present in hair color. The conditioners close the cuticle after coloring to seal in and protect the new color.


SCHOLAR ARTICLE:
http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.1973.tb00197.x/abstract

Hair Styling

Permanent Waves

These products are designed to permanently change the shape of hair. People with straight hair often use permanent waves to get a little curl in their hair. A permanent wave formula has a reducing agent like thioglycolic acid that reacts with the di-sulfur bonds in the cystine amino acids breaking down the hair structure. Hair is first shaped into curlers, then the product is put on hair. It begins reducing hair and is rinsed with water to stop the reaction. A neutralizing chemical like hydrogen peroxide, is added which reforms the di-sulfur bonds into the new configuration. Perms which intentionally curls hair, chemically increases the number of disulfide bonds by using an oxidizer to uncap the naturally caped sulfides in straight hair. As the name implies, these perms will stay "forever" curly. So, one chemical (a reducer) can make your hair straight, while another chemical (an oxidizer) can make your hair curly. An oxidizing agent, usually a dilute solution of hydrogen peroxide, (also called the neutralizer) is added to reform the disulfide bonds in their new positions. The permanent will hold these new disulfide bond positions until the hair grows out, since new hair growth is of course not treated.


SCOLAR ABSTRACT:
http://www.sciencedirect.com/science/article/pii/S0190962288701516

Hair Relaxers

These products do the opposite of permanent waves. They make curly hair permanently straight. The method is similar you chemically break down hair, reshape it, then reform the protein bonds in the new configuration. Hair is curly is because the keratin proteins contain amino acids called cysteines. These cysteines link to each other by disulfide bonds cap them so that they cannot c(two sulfur atoms connected to each other).The more disulfide bonds, the curlier the hair. Relaxers simply break these disulfide bonds and hemically reform. Classically, hair relaxers use a reducer or a base (the opposite of an acid) such as lye (sodium hydroxide) to break and cap these bonds, thus the neutralizing step stops the reaction. Sometimes ammonium thioglycolate is used but most often it is sodium hydroxide or lithium hydroxide. Unfortunately, sodium hydroxide can burn your skin and damage your hair. The gentler and safer commercial relaxers are still based on the same chemical reactions of breaking disulfide bonds and capping them. Disulfide bonds are not affected by water so when you break the bonds and cap them (in the case of relaxers) they will not go back to their original state.

This is the most damaging chemical treatment for hair!!

SCHOLAR ABSTRACT: refer to page 2
http://www.google.com.my/patents?hl=en&lr=&vid=USPAT4530830&id=3Po9AAAAEBAJ&oi=fnd&dq=hair+relaxers&printsec=abstract#v=onepage&q=hair%20relaxers&f=false

Perms and relaxings both eventually go away, not because the bonds reform, but because your original hair simply grows in, replacing your straightened or curled hair with what you had originally. These chemicals, however, have a tendency to damage your hair, until eventually your hair starts to thin and break, so too much styling can be bad for your hair's health. 

Browning of Apple

We noticed that after cutting an apple and left them for some time, the apple slices were becoming brownish. However, we always put them in salt water for some time before eating and the apple slices do not turn into brown color in a short period. Do you know why is it this happened?

This turning of color is called enzymatic browning. Enzymatic browning is a chemical process, involving polyphenol oxidase, catechol oxidase and other enzymes that create melanin and benzoquinone, resulting in a brown color. This process can be observed in some fruits, vegetables and also seafood.

Apples contain polyphenol oxidase enzyme that catalyzes the reaction between polyphenols (tyrosine), which are naturally present in apple tissues, and oxygen. Polyphenols are responsible for the color of many plants, such as apples. They are also part of the taste and flavor of beverages and are important anti-oxidants in plants. When we cut apples, polyphenols (tyrosine) in apples are unstable due to the fact that they undergo chemical and biochemical reactions. This cutting process breaks the apple cells and therefore the enzymatic oxidation occurred when it is exposed to oxygen. This enzymatic oxidation reaction leads to the formation of black-brown complexes called melanin, causing browning of apples.

                                                   Polyphenol oxidase

Equation:           Tyrosine                   -->                     Melanin

The reason why we put apple slices in salt water (sodium chloride) after cutting is that sodium chloride is a water-binding chemicals. Sodium chloride removes water molecules from the cells by binding to water. This removing of water in apple slices causing the polyphenol oxidase could not catalyzes the reaction between polyphenols and oxygen as water is absent. Without this reaction, the formation of melanin is stopped and apple slices will not turn brown.

            However, there is another more effective method to keep apple from turning brown after cutting. We can sprinkle some lime juice or lemon juice to the apple slices. Lemon juice and lime juice contains ascorbic acid which is vitamin C and citric acid. Ascorbic acid acts as anti-oxidant that prevent apple from being oxidized and turning brown. Oxygen preferentially reacts with the ascorbic acid, rather than with the phenolic compounds in the fruit or vegetable. Browning does not proceed until all the ascorbic acid is used up in the reaction.  Ascorbic acid also reacts with melanin to bleach them and thus the apple does not turn brown. Besides that, citric acid lowers the pH of the fruit tissue to retard the action of the polyphenol oxidase. Polyphenol oxidase works best in the range of pH 5.0 – 7.0 and denatured when pH level is lower than 3.0 while lime juice and lemon juice are in range of pH 2.0 - 2.5. Hence, keeping the apple slices from undergoing enzymatic browning reaction.

Apple slice that put in salt water.

                      Apple slice that exposed to air.

               
*Click here to view an article from 'Jounal of Agricultural and Food Chemistry' .