Chemy In My Daily Life

What preserve food??

2009-07-31T20:44:00.003+08:00

In our daily life, most of the food we eat now are preserved. What is the common preservative of the food? Food shelf life is a primary concern for both food manufacturers and marketers. A food product's ability to uphold standards of safety and quality for prolonged periods directly affects sales and customer satisfaction.

The 'freshness' of the food is due to the oxidation of the food. Oxidation occurs when molecules in chemically unsaturated fats and oils react with oxygen to form free radicals. Other byproducts are aldehydes, ketones, acids and alcohols, which result in the harsh flavors, odors, changes in texture and loss of nutritional value associated with rancidity. Antioxidants can block the formation of free radicals in food fats by stabilizing their molecular structure.

Here come the antioxidants
Butylated hydroxyanisole (BHA) and the related compound butylated hydroxytoluene (BHT) are phenolic compounds that are often added to foods to preserve fats.

BHA and BHT are antioxidants. Oxygen reacts preferentially with BHA or BHT rather than oxidizing fats or oils, thereby protecting them from spoilage. In addition to being oxidizable, BHA and BHT are fat-soluble. Both molecules are incompatible with ferric salts. In addition to preserving foods, BHA and BHT are also used to preserve fats and oils in cosmetics and pharmaceuticals.

Gangloside

2009-07-28T20:03:00.000+08:00

From a advertisement that i watch from the tv, it shows that their product which is a milk powder rich in "Gangloside". From the advertisment, gangloside can connect the nerve of the brain more so the childen is more clever~!!?? SO I am wondering what is gangloside? Now let me talk about gangloside~~~

The name ganglioside was first applied by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion cells of brain. For an easily understand, gangloside is lipid that attach on oligosaccaride chain. Ganglioside is a compound composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids linked on the sugar chain.

Gangloside

The function of gangloside
Gangliosides found on the surface of oligosaccharide provide cells with distinguishing surface markers that can serve in cellular recognition and cell-to-cell communication. Structures similar to the ABO blood group antigens on the surface of human cells can be oligosaccharide components of glycosphingolipids in addition to being linked to proteins to form glycoproteins.

As the brain develops, there is an increase in the content of gangliosides and in their degree of sialylation. There are large differences between species and tissues. For example, during embryogenesis and the postnatal period in the human central nervous system, the total amount of gangliosides increases approximately threefold.

In mouse brain, the total amount of gangliosides is almost 8-fold greater in adults than in embryos, with a similar shift in composition from simple to more complex gangliosides governed mainly by changes in the expression level and activity of the glycosyltransferases. The techniques of molecular biology, which enable specific enzymes to be eliminated from experimental animals, are now leading to a better understanding of the function of specific gangliosides.

Analysis of Gangloside
Gangliosides are not the easiest of lipids to analyse, as they are most 'un-lipid-like' in many of their properties. For example, in the conventional Folch method for extraction of lipids from tissues, the gangliosides partition into the aqueous layer rather than with the conventional lipids in the chloroform layer. Nonetheless, methods have been devised for quantitative extraction, and they can then be sub-divided into the various molecular forms by high-performance thin-layer chromatography (or less commonly by high-performance liquid chromatography). Nowadays, mass spectrometry is the probably main method for structural analysis and especially for identifying and sequencing the carbohydrate chains, with invaluable assistance from nuclear magnetic resonance spectroscopy.

One of the type of gangloside -- GM2

Gangloside in milk powder
A method of preparing Ganglioside GM3 which comprises converting Ganglioside GD3 into Ganglioside GM3 in an alkaline condition is disclosed. The conversion of Ganglioside GD3 into Ganglioside GM3 is preferably carried out by thermal treating Ganglioside GD3 in an alkaline condition. The thermal treatment is preferably carried out at a pH ranging from 8 to 11 and at a temperature ranging from 30° C. to 140° C.
The Ganglioside GM3 prepared by the method of the present invention is useful as a reagent used in medical, pharmaceutical and biochemical fields, and is also useful as a material for pharmaceuticals, cosmetics, foods, beverages and animal feeds.
Gangloside which develope in milk poewdee for children can help the brain development of children. Children who drink milk that contain gangloside, their brain development will be better because of the joining of the nerve cell of the brain.

HOT!!!!

2009-06-07T19:30:00.009+08:00

Recently the weather was soooo hot!!!If can stay at the air-conditioned room is the best!!

How air conditioner works?
Most people think that air conditioners lower the temperature in their homes simply by pumping cool air in. What's really happening is the warm air from your house is being removed and cycled back in as cooler air. This cycle continues until your thermostat reaches the desired temperature.

An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant, like Freon, to provide cooling. The mechanics of the Freon evaporation cycle are the same in a refrigerator as in an air conditioner.
Freon is DuPont's trade name for its odorless, colorless, nonflammable, and noncorrosive chlorofluorocarbon and hydrochlorofluorocarbon refrigerants.

A simple stylized diagram of the refrigeration cycle: 1.condensing coil 2. expansion valve 3. evaporator coil 4. compressor

1.The compressor compresses cool Freon gas, causing it to become hot, high-pressure Freon gas (red in the diagram above).

2.This hot gas runs through a set of coils so it can dissipate its heat, and it condenses into a liquid.

3.The Freon liquid runs through an expansion valve, and in the process it evaporates to become cold, low-pressure Freon gas (light blue in the diagram above).

4.This cold gas runs through a set of coils that allow the gas to absorb heat and cool down the air inside the building.
Mixed in with the Freon is a small amount of lightweight oil. This oil lubricates the compressor.

Air conditioners help clean your home's air as well. Most indoor units have filters that catch dust, pollen, mold spores and other allergens as well as smoke and everyday dirt found in the air. Most air conditioners also function as dehumidifiers. They take excess water from the air and use it to help cool the unit before getting rid of the water through a hose to the outside. Other units use the condensed moisture to improve efficiency by routing the cooled water back into the system to be reused.

Type of air conditioning
Refrigeration cycle
In the refrigeration cycle, a heat pump pumps heat from a lower temperature heat source into a higher temperature heat sink. Heat would naturally flow in the opposite direction. This is the most common type of air conditioning. A refrigerator works in much the same way, as it pumps the heat out of the interior into the room in which it stands.

Refrigerants
"Freon" is a trade name for a family of chlorofluorocarbon (CFC) refrigerants manufactured by DuPont and other companies. These refrigerants were commonly used due to their superior stability and safety properties. Unfortunately, evidence has accumulated that these chlorine bearing refrigerants reach the upper atmosphere when they escape. The chemistry is poorly understood but general consensus seems to be that CFCs break up in the stratosphere due to UV-radiation, releasing their chlorine atoms. These chlorine atoms act as catalysts in the breakdown of ozone, which does severe damage to the ozone layer that shields the Earth's surface from the strong UV radiation. The chlorine will remain active as a catalyst until and unless it binds with another particle forming a stable molecule.

FREON
Freon is not exact a chemical. It is actually a trade name that describes a whole class of chemicals used in refrigeration. Most of the chemicals included under the trade name of Freon are known as chlorofluorocarbons(CFCs). This means that their chemical structure is made up of the main chemical building blocks of carbon and hydrogen, but they also include chlorine and fluorine as well.

The most serious side effect of freon exposure would occur at the time of initial exposure. People who have a history of heart problems should be very concerned about Freon because it can cause cardiac arrhythmia (irregular heartbeat), and palpitations at very high concentrations. For people who have a history of heart problems, being exposed to small amounts of Freon from leaking appliances should not pose any significant health risk.

Fortunately, Freon does not have serious long term health consequences. It is not a carcinogen, teratogen, or mutagen, and it does not damage the liver. When it is inhaled, it is rapidly excreted by exhalation, and it is not significantly accumulated in the body. This means that breathing low concentrations of freon from a leaking refrigerator or air conditioner over a long period of time is unlikely to have a cumulative effect, and thus few, if any, long term health effects.

If you discover that you have a Freon leak, contact a technician for repairs immediately. Open up windows and doors and use fans to help move the air out of the area. Remove yourself and your pets to an area of fresh air, and if you feel any unusual health effects, seek medical care. If you have chronic heart conditions, consider having your Freon containing appliances checked regularly for leaks.

Air conditioner equipments
There are few equipments to combine and makes up the air conditioner system:
1.Window and through-wall units
2.Evaporative coolers
3.Central air conditioning

Coffeee~~~

2009-05-31T16:41:00.012+08:00

Coffee is a beverage, which most Americans drink, but nowadays, coffee is one of the most popular beverages worldwide. For some people, a cup of coffee during every morning is necessary for them. For me, I'm a coffee lover too, maybe is because of my mom likes coffee. There are different kind of coffee beverage such as mocha, cappuccino, double espresso, Yuan yang, coffee blended, liqueur coffee and many more.
Coffee was first consumed in the 9th century, when it was discovered in the highlands of Ethiopia.From there, it spread to Egypt and Yemen, and by the 15th century, it had reached Azerbaijan, Persia, Turkey, and northern Africa. From the Muslim world, coffee spread to Italy, then to the rest of Europe, to Indonesia, and to the America.

HOW COFFEE MADE?

The process of making coffee is a complex procedure.

1. The first step in the process of coffee making is picking up every cherry carefully. The picking of cherries has to be very precise because if the cherry is picked up to early it will lack of essential sweetness, but if the cherry is picked up to late it will be sour.

2. The second step is the process in which they take out all the soft juicy fruit of the cherry and leave the coffee bean pealed. This is called “despulpado.” During this process the coffee is separated the by altitudes, and quality.

3. The next step is fermentation, in this process they leave the coffee beans in long tanks for the coffee to release all the honey left from the pulp.

4. Then washing the coffee beans. During this process the beans are placed in large tanks filled with water pressure, which leaves the beans with no honey leftovers. It also separates the coffee beans by quality, the beans that float are the low quality beans and the ones that are in the bottom of the tank are the good quality beans.

5. During the drying process all the beans are arranged in a patio outdoors, the wind and the sun are in charge of drying the beans.

6. The last step roasting the coffee, in this process is where the roaster will decide the taste of the batch of coffee being roasted. All these steps to follow are the steps coffee beans go through before consumers can actually drink it.

WHY COFFEE MAKES US AWAKE?

This is because the coffee contains caffeine.
Caffeine

But why caffeine has such a strong effect on us? Caffeine operates using the same mechanisms of amphetamines, cocaine, and heroin to stimulate the brain, though with milder effects. It manipulates the same channels as the other drugs, and that is one of the things that gives caffeine its addictive qualities.

There is a chemical in our brain called adenosine, that binds to certain receptors and slows down nerve cell activity when we are sleeping. For a nerve cell, caffeine "looks like" adenosine and it binds to the adenosine receptors. However, as it's not really adenosine, it doesn't slow down the cell's activity like adenosine would. So the cell cannot "see" adenosine anymore because caffeine has taken up all the receptors adenosine binds to. Then instead of slowing down because of the adenosine level, the cells speed up.

The pituitary gland sees all of this activity and thinks some sort of emergency must be occurring, so it releases hormones that tell the adrenal glands to produce adrenaline. Adrenaline is the "fight" hormone, and it makes your heart to beat faster, the breathing tubes to open up, the liver to release sugar into the bloodstream for extra energy and your muscles to tighten up, ready for action. Because of this, after consuming a big cup of coffee your muscles tense up, you feel excited and you can feel your heart beat increasing.

EFFECT OF CAFFEINE?

Various other studies have shown apparent reductions in the risks of Alzheimer's disease, Parkinson's disease, heart disease, diabetes mellitus type 2, cirrhosis of the liver, and gout. A longitudinal study in 2009 showed that moderate drinkers of coffee (3-5 cups per day) had lower chances of developing dementia, in addition to Alzheimer's disease. It increases the risk of acid reflux and associated diseases. Some health effects of coffee are due to its caffeine content, as the benefits are only observed in those who drink caffeinated coffee while others appear to be due to other components. For example, the antioxidants in coffee prevent free radicals from causing cell damage.

On the other hand, coffee consumption can lead to iron deficiency anemia in mothers and infants. Coffee also interferes with the absorption of supplemental iron.

HOW IS COFFEE DECAFFEINATED?

Depending on the type of coffee and method of preparation, the caffeine content of a single serving can vary greatly. On average, a single cup of coffee (about 200 ml) or a single shot of espresso (about 30 ml) can be expected to contain the following amounts of caffeine:

Drip coffee: 115–175 mg (560–850 mg/L)
Espresso: 60 mg (2000 mg/L)
Brewed/Pressed: 80–135 mg (390–650 mg/L)
Instant: 65–100 mg (310–480 mg/L)

There are few ways to remove the caffeine in the coffee:
1. Genetic engineering: Investigation on ways to inactivate the gene that codes for caffeine synthesis, the enzyme which catalyzes the caffeine synthesis. Then coffee plants unable to produce caffeine could be grown.

Dichloromethane

Ethyl Acetate
2. Water extraction: At the beginning solvents like dichloromethane or ethyl acetate were used because they dissolve selectively the caffeine. But because of their toxicity nowadays water is used instead. Hot water extracts both flavor ingredients and caffeine from green coffee beans. Then the extract is passed through activated charcoal and most of the caffeine is removed. Finally, soaking the original beans in the decaffeinated extract restores most of their flavor.

3. Supercritical fluid CO2 extraction: Supercritical fluids have both gas like and liquid like properties, they fill the container like a gas but can dissolve substances like a liquid. In the caffeine extraction process, this fluid is forced through green coffee beans, it penetrates deep into the beans and dissolves most of the caffeine present.
What are supercritical fluids?
A SCF is defined as a substance above its critical temperature (TC) and critical pressure (PC). The critical point represents the highest temperature and pressure at which the substance can exist as a vapour and liquid in equilibrium.

Having coffee moderately is alright, but if we over drinking of coffee will have negative effect on our body. Therefore, controlling drinking of coffee is important!!~~

What is antioxidant?

2009-05-24T11:40:00.021+08:00

In these few years, there are a lot of food products promoting antioxidant. Besides, there are some skin care products and supplements also promoting antioxidant. But actually what is antioxidant? I'm wondering what is the function of antioxidant? What effect does antioxidant bring to our body?

Space-filling model of the antioxidant
The yellow sphere is the redox-active sulfur atom that provides antioxidant activity, while the red, blue, white, and dark grey spheres represent oxygen, nitrogen, hydrogen, and carbon atoms, respectively.

Now I will find out what is antioxidant. You may have heard about the health benefits of antioxidants, but do you know what an antioxidant is? Antioxidants work by significantly slowing or preventing the oxidative or damage from oxygen(process caused by substances called free radicals that can lead to cell dysfunction). Antioxidants may also improve immune function and perhaps lower your risk for infection and cancer.

In chemistry, free radicals are atoms, molecules, or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly reactive, so radicals are likely to take part in chemical reactions.

An antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent. Oxidation reactions can produce free radicals, which start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. As a result, antioxidants are often reducing agents. Antioxidants that are reducing agents can also act as pro-oxidants. For example, vitamin C has antioxidant activity when it reduces oxidizing substances such as hydrogen peroxide,however, it will also reduce metal ions that generate free radicals through the Fenton reaction.

2 Fe3+ + Ascorbate → 2 Fe2+ + Dehydroascorbate
2 Fe2+ + 2 H2O2 → 2 Fe3+ + 2 OH· + 2 OH

Antioxidants are a diverse group of chemicals that can be naturally found in vegetables, fruits and plants. Antioxidants are also synthesized in our body. Examples of dietary antioxidants are vitamin E, C, A, phenolic acids, selenium, chlorophyll and cholorphyll derivatives, carotenoids, flavonoids, glutathione, coenzyme Q 10, melatonin, and lycopene. Synthetic dietary antioxidants include butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Chemicals with antioxidant activity produced in human body include uric acid, high density lipo-protein (HDL), and amino acids such as arginine.

Antioxidants protect the body from oxidative damage induced by free radicals and reactive oxygen species by
(1) suppressing their formation
(2) acting as scavengers
(3) acting as their substrate

Antioixdants are essential for proper function of the immune system. If the level of free radicals in the immune cells surpasses beyond the normal level, they negatively affect the immune system. On the other hand, antioxidants act as scavengers of the free radicals in cells and there fore promote our immunity.

Therefore, to have enough antioxidant to maintain good health we can uptake food that contain or produce antioxidant. A variety of fruits, vegetables, nuts, whole grain cereals and legumes, tea, red wine, and herbs such as rosemary extract are rich sources of natural antioxidants. The benefit of eating whole fruits, vegetables, and whole grain foods, in contrast to antioxidant supplements, is that they contain a variety of natural antioxidants. A combination of multiple antioxidants has greater health benefit than when an antioxidant is taken individually. Furthermore, the antioxidant content tends to be high on their outer layer of the plant products. For example, in cereals, the bran is richer in antioxidants such as phenolic acids, and phytic acid than the inner part of the grain.

Food high in antioxidants include fruits such as apple, grape, grapefruit, crane berry, black berry and blueberry. Even though, comprehensive studies on antioxidant content of foods are yet to come, among the best antioxidant sources are crane berry, black berry and blue berry. Vegetables are also rich antioxidant sources. Red bean, pinto bean, kidney bean, carrot, tomato, garlic and Russet potato are among the vegetables high in antioxidant content and categorized among the best antioxidant sources. Other important sources of antioxidants are green tea, black tea, herbal tea, spices, red wine, ginger, and garlic.

Antioxident can prevent stroke and neurodegenerative diseases. However, it is unknown whether oxidative stress is the cause or the consequence of disease. Antioxidants are also widely used as ingredients in dietary supplements in the hope of maintaining health and preventing diseases such as cancer and coronary heart disease. Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials did not detect any benefit and suggested instead that excess supplementation may be harmful.In addition to these uses of natural antioxidants in medicine, these compounds have many industrial uses, such as preservatives in food and cosmetics.

To obtain antioxidant, the best way is to uptake diferent kind of fruits and vegatable, in contrast to antioxidant supplements. A combination of multiple antioxidants has greater health benefit than when an antioxidant is taken individually. Prevention is better than cure. To maintain good health, having a balanced diet is important!

What you using to clean your face?

2009-05-10T21:46:00.010+08:00

Most common step of taking care of our face is wash face every day to keep our face clean and healthy. BUT, are you all actually know what ingredients of a face cleanser??

For normal facial cleanser, the ingredients were water, glycerin, potassium cocoyl glycerinate, polyquaternium-6/polyquaternium-10, lauric acid, citric acid, tetrasodium EDTA, BHT, DMDM hydantoin, frangrance, propylene glycol and stearic acid.

What is the use of the ingredients?

glycerin : act as humectant(to help matain moisture).

Glycerin

potassium cocoyl glycerinate : act as cleaning agent.

polyquaternium-6/-10, propylene glycol : provide excellent moistorization.
lauric acid, stearic acid : act as foam thickener. Lauric acid
citric acid, tetrasodium EDTA, BHT, DMDM hydantoin : act as preservative.
Tetrasodium EDTA

DMDM Hydantoin

frangrance : act as aromatizer.

Some of the people face oily skin problem. One of the reason of oily skin is due to the over active of sebaceous glands. The negetive aspects of oily skin are blackheads, clogged pores and result to pimples. To overcome the problem, you need to remove excess sebum of the surface of the skin without complete removal of skin lipids.

A method to clean an oily face is clean the face with natural skin cleanser formulated specially for oily skin. The pH of the cleansers should be between 4.5 to 5.5, since the skin pH is approximately 5.4. Gel type face cleansers work best for oily skin. For oily skin products should not include waxes or other synthetic lipid agent that could aggravated the skin. Some cleansing products have low concentration of hydroxy acids, which remove dead cell from the upper layer of the stratum corneum. People with oily skin should use a moisturizers with humactent to give moisture to the skin.

Skin Structure

hyroxy acids:consists of carboxylic acid substituded the hydroxy group on the adjacent carbon. It is derived from food products including glycolic acid (from sugar cane), malic acids(from apple), citric acid (from fruits), lactic acid (from sour milk) and tartaric acid (from grape wine).

On the other hand, there are some people having dry skin. This may due to over exposure to sunlight, deficiency of vitamin A and vitamin B or wash face too frequently. For dry skin, chossing face cleanser that contains sodium hyaluronate that can hydrate the skin. Besides, cleansers that contains stearic acid that purges the skin from toxins and debris.

Nowadays, different types of cleansers have been developed for people that with different skin types. Strong type cleansers are more suitable for oily skin to prevent the dirt clog in the pores. However, the strong cleansers may be over dry and irritate dry skin. Dry skin may require creamy-lotion type cleansers to prevent the skin become over dry. If you have dry or sensitive skin, it is better to choose alcohol free cleanser.

A good cleanser is neccesary for everyone. Choosing the adequate face cleanser is very important for everyone. Good cleansers help to remove of dirt and debris, eliminates surface bacteria, imparts fresh skin and prevent oil secretion.