Idaho Web Design Tools
|
|
Aspartame is a compound of two amino acids -- aspartic acid and phenylalanine. Because it is essentially half phenylalanine, people who have the genetic disease phenylketonuri (PKU) cannot metabolize phenylalanine normally need to avoid diet drinks and other products containing aspartame (trade name: NutraSweet). Aspartame (formula C14H18N2O5) is the name for an artificial, non-carbohydrate sweetener, aspartyl-phenylalanine-1-methyl ester; i.e., the methyl ester of the dipeptide of the amino acids aspartic acid and the essential amino acid phenylalanine. Under strongly acidic or alkaline conditions, aspartame first generates methanol by hydrolysis. Under more severe conditions, the peptide bonds are also hydrolyzed, resulting in the free amino acids.
Aspartame is considered by some scientists to be a neurotoxin, a substance that is detrimental to the nervous system. This allegation remains controversial. At elevated temperatures of about 90° Fahrenheit, a component of aspartame can convert to formaldehyde. High concentrations of formaldehyde can kill cells and tissues. Furthermore, formaldehyde can, in turn, be converted to formic acid, which can cause metabolic acidosis. Whether these changes are detrimental to the nervous system is not known.
Like many other peptides, aspartame may hydrolyze (break down) into its constituent amino acids under conditions of elevated temperature or high pH. This makes aspartame undesirable as a baking sweetener, and prone to degradation in products hosting a high-pH, as required for a long shelf life. Aspartame’s stability under heating can be improved to some extent by encasing it in fats or in maltodextrin. Aspartame’s stability when dissolved in water depends markedly on pH. At room temperature, it is most stable at pH 4.3, where its half-life is nearly 300 days. At pH 7, however, its half-life is only a few days. Most soft-drinks have a pH between 3 and 5, where aspartame is reasonably stable. In products that may require a longer shelf life, such as syrups for fountain beverages, aspartame is sometimes blended with a more stable sweetener, such as saccharin.
In products such as powdered beverages, aspartame’s amino group can undergo a Maillard reaction with the aldehyde groups present in certain aroma compounds. The ensuing loss of both flavor and sweetness can be prevented by protecting the aldehyde as an acetal.
Alleged harmful effects of aspartame ingestion include seizures and a change in the level of dopamine, a brain neurotransmitter. Symptoms associated with lupus, multiple sclerosis, and Alzheimer's disease have been claimed to result from an excess intake of aspartame. As well, aspartame consumption is claimed to increase the difficulty of diet-dependent diabetics in regulating their blood glucose level.
J.W. Childs Equity Partners II, L.P. completed its purchase of the NutraSweet Co. from Monsanto, a wholly-owned subsidiary of Pharmacia Corp., for $440 million in cash. The sale includes the sweetener business, the NutraSweet brand name and the new sweetener, neotame. This sweetener is marketed under a number of trademark names, such as Equal, and Canderel, and is an ingredient of approximately 6,000 consumer foods and beverages sold worldwide. It is commonly used in diet soft drinks, and is often provided as a table condiment. It is also used in some brands of chewable vitamin supplements. However, aspartame is not always suitable for baking, because it often breaks down when heated and loses much of its sweetness. In the European Union, it is also known under the E number (additive code) E951. Aspartame is also one of the sugar substitutes used by diabetics. Nonetheless, aspartame has been a subject of a vigorous public controversy
Aspartame from:
Aspartic acid: An amino acid, one of the 20 building blocks of protein. A nonessential amino acid, C4H7NO4, found especially in young sugar cane and sugar-beet molasses. Aspartic acid was discovered in protein in 1868. It has a role as a neurotransmitter. Aspartic acid is also manufactured from other amino acids in the liver; it does not have to be obtained directly through the diet.
Aspartic acid is very important in the urea cycle for the proper elimination of waste products from dietary protein. Poor control of the urea cycle may be related to symptoms such as chronic headache, fatigue, irritability, lack of concentration, mental confusion, and intolerances to various foods, particularly high protein foods. Deficiencies of a nonessential amino acid will not occur if a well-balanced diet is consumed because the intake of proper foods will allow the body to produce exactly the amount of amino acid required to function optimally.
Aspartic acid has been used as mineral salts such as magnesium aspartate or potassium aspartate to help improve energy production in exercising muscles.
Phenylalanine is an essential alpha-amino acid. It exists in two forms, a D and an L form, which are enantiomers (mirror-image molecules) of each other. It has a benzyl side chain. Its name comes from its chemical structures consisting of aphenyl group substituted for one of the hydrogens in the side chain of alanine. Because of its phenyl group, phenylalanine is an aromatic compound. At room temperature, it is a white, powdery solid.
Phenylketonuria (commonly known as PKU) is an inherited disorder that increases the amount of the amino acid phenylalanine to harmful levels in the blood. (Amino acids are the building blocks of proteins.) If PKU is not treated, excess phenylalanine can cause mental retardation and other serious health problems. Phenylketonuria is a subtype of hyperphenylalaninemia.
The signs and symptoms of this disorder vary from mild to very severe. The most severe form of the disorder is known as classic PKU. Infants with classic PKU appear normal until they are a few months old. Without treatment, these children develop permanent mental retardation and behavioral problems. Seizures, delayed development, and movement disorders are also common. Many children have a musty or "mouse-like" odor as a side effect of too much phenylalanine in the body. Children with classic PKU tend to have lighter skin and hair than unaffected family members, because phenylalanine is important for skin pigmentation. Children with the disorder are also likely to have skin disorders such as eczema.
Less severe forms of PKU (sometimes called moderate or mild PKU) have a smaller risk of brain damage. People with very mild cases may not require treatment with a special diet.
Babies born to mothers with high levels of phenylalanine have a high risk of mental retardation because they are exposed to very high levels of phenylalanine before birth. These infants may also grow more slowly than other children and may have heart defects or other heart problems, small head size (microcephaly), and behavioral problems. Affected women with uncontrolled phenylalanine levels also have an increased risk of pregnancy loss.
PKU is found in about 1 in 10,000 Caucasian (white) newborns. The disorder occurs much less frequently in infants of Japanese, Ashkenazi Jewish, Finnish, and African backgrounds. PKU is most common in Turkey, where 1 in 2,600 newborns is affected.