Bromelain
Bromelain can refer to one of two protease enzymes extracted from the plant family Bromeliaceae, or it can refer to a combination of those enzymes along with other compounds produced in an extract.

# Components
Bromelain is a mixture of sulfur-containing protein-digesting enzymescalled proteolytic enzymes or proteasesand several other substances in smaller quantities. The two main enzymes are:
- stem bromelain - EC 3.4.22.32
- fruit bromelain - EC 3.4.22.33
The other substances include peroxidase, acid phosphatase, protease inhibitors, and calcium.

# History
The first isolation of bromelain was recorded by the Venezuelan chemist Vicente Marcano (BU1 1.Phar. 5,77) in 1891 from the fruit of pineapple. In 1892, Chittenden, assisted by Joslin and Meara, investigated the matter fully (Trans.  Conn. Acad. Arts Sci. 8, 281-308), and called it 'bromelin'. Later the term 'bromelain' was introduced and originally applied to any protease from any plant member of the plant family Bromeliaceae.
Bromelain was first introduced as a therapeutic supplement in 1957. Research on bromelain apparently was first conducted in Hawaii but more recently has been conducted in countries in Asia, Europe and Latin America. Germany has recently taken a great interest in bromelain research; bromelain is currently the 13th most widely used herbal medicine in Germany.

# Source
Bromelain is present in all parts of the pineapple plant (Ananas comosus) but the stem is the most common commercial source, presumably because it is readily available after the fruit has been harvested. Pineapples have had a long tradition as a medicinal plant among the natives of South and Central America. However, just eating pineapple will not give you a great deal of extra bromelain, because it is mostly concentrated in the stem, which is not nearly as tasty (albeit still edible).

# Uses

## Meat tenderizing
Along with papain, Bromelain is one of the most popular substances to use for meat tenderizing.
Historically, meat tenderizing enzymes were often injected into the muscle of a food animal while it was still living.  This practice was deemed unethical, and has been largely discontinued, replaced with various postmortem application methods which are acceptable for lesser quality cuts.
Today, approximately 90% of meat tenderizer use is in consumer households.  Bromelain is sold in a powdered form, which is combined with a marinade or directly sprinkled on the uncooked meat.  The enzyme will penetrate the meat, and by a process called forking, cause the meat to be tender and palatable when cooked.  If the enzyme is allowed to work for too long, the meat may become too "mushy" for many consumers' preferences

## Medical uses
Bromelain can be used in a vast array of medical conditions. It was first introduced in this area in 1957, and works by blocking some proinflammatory metabolites that accelerate and worsen the inflammatory process. It is an anti-inflammatory agent, and so can be used for sports injury, trauma, arthritis, and other kinds of swelling. Its main uses are athletic injuries, digestive problems, phlebitis, sinusitis, and aiding healing after surgery.
It has also been proposed in the use of arthritis, chronic venous insufficiency, easy bruising, gout, hemorrhoids, menstrual pain, autoimmune disorders, and ulcerative colitis.
Studies have shown that bromelain can also be useful in the reduction of platelet clumping and blood clots in the bloodstream, especially in the arteries.
It may have treatment potential for HIV.
Its side effects include nausea, vomiting, diarrhea, menorrhagia (excessively heavy menstrual flow) and possible allergic reactions. One study has also associated Bromelain with increased heart rate.
Bromelain supplementation up to 460 mg has been shown to have no effect on human heart rate or blood pressure; however, increasing doses up to 1840 mg have been shown to increase the heart rate proportionately.

# Production
It is produced in Thailand, among other tropical parts of the world, where pineapples are grown.
Bromelain is prepared from the stem part of the pineapple plant after harvesting the fruit. This stem part is peeled, crushed and pressed to get the juice containing the soluble Bromelain enzyme.
Further processing includes concentration of the pressed juice to get a purified enzyme. This process is carried out in factories under strictly controlled conditions to assure microbiological quality and enzyme purity.
The Bromelain products are all supplied as powder.

# Other plant proteases
Other plant proteases include papain (from the papaya), actinidin (from the kiwi fruit), and ficin (from the fig). These proteases may induce a prickly sensation in the mouth when consumed.