Citric acid

Citric acid is a weak organic acid found in citrus fruits. It is a good natural preservative and is also used to add an acidic (sour) taste to foods and soft drinks. In biochemistry, it is important as an intermediate in the citric acid cycle and therefore occurs in virtually all living things. It also serves as an environmentally friendly cleaning agent and acts as an antioxidant.

Pure citric acid is a white crystalline powder. Its chemical formula is C6H8O7 and the structure is:

This structure is reflected in the systematic name 2-Hydroxypropane-1,2,3-tricarboxylic acid.

The acidity of citric acid results from the three carboxy groups COOH which can lose a proton in solution. If this happens, the resulting ion is the citrate ion. Salts of citric acid containing this ion are called citrates. An important one is calcium citrate or "sour salt", which is commonly used in the preservation and flavoring of food.

Citric acid was first isolated by Carl Wilhelm Scheele in 1784 from lemon juice. Nowadays, it is produced by fermentation of sugar solution by the fungus Aspergillus niger.

UK pharmacies control the sale of Citric acid. Citric acid is a popular buffer used to increase the solubility of street heroin in Scotland. Single-use citric acid sachets have been used as an inducement to get heroin users to exchange their dirty needles for clean needles in an attempt to decrease the spread of AIDS and hepatitis. See the .pdf article here. Other acidifiers used for brown heroin are ascorbic acid, acetic acid, and lactic acid: in their absence, the drug abuser will often substitute lemon juice or vinegar.

The CAS number of pure citric acid is 77-92-9.



In the News

Fescue, A Common Lawn Grass, Use Natural Herbicide To Controls Weeds
Certain varieties of common fescue lawn grass come equipped with their own natural broad-spectrum herbicide that inhibits the growth of weeds and other plants around them. Fescue grass roots exude a yellow material that contains an amino acid called m-tyrosine in large amounts.

United States Department of Agriculture (USDA): Hurricane Katrina Reli
"Information for Food and Housing Assistance, Disaster Cleanup, Agency Resources, Recovery, and Consumers, and for USDA Personnel In the Affected Areas."This site provides news and information about USDA activities following Hurricane Katrina, such as relief programs for farmers, emergency food assistance, the Food Stamp and child nutrition programs, and the Rural Development program. Also includes links to related U.S. government sites.

Everything I Need to Know About (Real) Robots I Learned From Transform
Transformers don’t care about people, period. That's what I learned growing up in the 1980s, religiously watching a race of robot Titans from outer space wage a secret war on Earth.

Link Found Between Periodontal Disease And Pancreatic Cancer
In a new study, researchers at the Harvard School of Public Health (HSPH) and Dana-Farber Cancer Institute found that periodontal disease was associated with an increased risk of cancer of the pancreas.

Finger Length Predicts Physically Aggressive Personalities, Study Show
Dr. Peter Hurd initially thought the idea was "a pile of hooey", but he changed his mind when he saw the data. Hurd and his graduate student Allison Bailey have shown that a man's index finger length relative to ring finger length can predict how inclined that man is to be physically aggressive. Women do not show a similar effect.

Oliver Sacks on Earworms, Stevie Wonder and the View From Mescaline Mo
Famed neurologist riffs about music and how the brain experiences it. It's all here in a longer version of the interview from the October issue of Wiredmagazine.

DVD Game Battles Child Obesity
Body Mechanics teaches kids how to avoid being overweight as they join forces with superheroes against villains like Col Estorol and Betes II. By the Associated Press.

Stem Cells' New Role: Kingmaker
A veteran political fund-raiser hopes to harness the public's growing support for stem cell research in an effort to sway congressional elections in several states. By Kristen Philipkoski.

New Gene Silencing Therapy For Cervical Cancer
Researchers at The University of Queensland's (UQ) Centre for Immunology and Cancer Research (CICR), based at the Princess Alexandra Hospital, have pioneered a new approach for the treatment of cervical cancer.

Fossweb: Plant and Animal Care
This site provides suggestions for the use of specific plants and animals in classroom settings, including habitat details, what to do when they arrive, and care instructions. "The animals in the modules were selected because they are abundant, safe for students, easy to care for, and hardy and well-adapted to classroom environments."Some of the organisms include ants, earthworms, Madagascar hissing cockroaches, bulbs, and seeds. From the Lawrence Hall of Science, University of California, Berkeley.


MP3 Music Downloads

Preview songs, Download Free Music,Burn CDs at ITunes.com
iTunes_RGB_9mm

 

Google




InformationQuickFind.com - Find Information Fast

Links