[size=14pt]
Alternative sources of rennet[/size][
edit] Because of the limited availability of mammalian stomachs for rennet production, cheese makers have looked for other ways to coagulate the milk since at least
Roman times. There are many sources of enzymes, ranging from plants, fungi, and microbial sources, that can substitute for animal rennet. Cheeses produced from any of these varieties of rennet are suitable for
lacto-vegetarians to consume. Fermentation produced chymosin (FPC)(see below) is used more often in industrial cheesemaking in North America and Europe today because it is less expensive and of higher quality than animal rennet.[sup][1][/sup]
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Vegetable rennet[/size]
[
edit] Many plants have coagulating properties.
Homer suggests in the
Iliad and the
Odyssey that the Greeks used an extract of
fig juice to coagulate milk.[sup][2][/sup] Other examples include
dried caper leaves,[sup][3][/sup]
nettles,
thistles,
mallow, and
Ground Ivy (Creeping Charlie). Enzymes from thistle or
cynara are used in some traditional cheese production in the
Mediterranean. Phytic acid, derived from unfermented
soybeans, or Fermentation-Produced Chymosin (FPC) may also be used.
Vegetable rennets are also suitable for
vegetarians.
Vegetable rennet might be used in the production of
kosher and
halal cheeses but nearly all kosher cheeses are produced with either microbial rennet or FPC.[
citation needed] Worldwide, there is no industrial production for vegetable rennet. Commercial so-called vegetable rennets usually contain rennet from the
mold Mucor miehei - see microbial rennet below.
[size=14pt]
Microbial rennet[/size]
[
edit] Some
molds such as
Rhizomucor miehei are able to produce proteolytic enzymes. These molds are produced in a
fermenter and then specially concentrated and purified to avoid contamination with unpleasant byproducts of the mold growth. At the present state of scientific research, governmental food safety organizations such as the
European Food Safety Authority deny QPS (Qualified Presumption of Safety) status to enzymes produced especially by these
molds.
The flavor and taste of cheeses produced with microbial rennets tend towards some bitterness, especially after longer maturation periods.[sup][4][/sup] Cheeses produced this way are suitable for
vegetarians, provided no animal-based alimentation was used during the production.
[size=14pt]
Fermentation-produced chymosin (FPC)[[[/size]
url=http://en.wikipedia.org/w/index.php?title=Rennet&action=edit§ion=7]edit[/url]] Because of the above imperfections of microbial and animal rennets, many producers sought further replacements of rennet. With the development of genetic engineering, it became possible to extract rennet-producing genes from animal stomach and insert them into certain
bacteria,
fungi or
yeasts to make them produce
chymosin during fermentation. The genetically modified microorganism is killed after fermentation and chymosin isolated from the fermentation broth, so that the fermentation-produced chymosin (FPC) used by cheese producers does not contain any GM component or ingredient. FPC is identical with chymosin made by an animal, but is produced in a more efficient way. FPC products have been on the market since 1990 and have been considered in the last 20 years the ideal milk-clotting enzyme.[sup][5][/sup]
FPC was the first artificially produced enzyme to be registered and allowed by the
US Food and Drug Administration. In 1999, about 60% of US
hard cheese was made with FPC[sup][6][/sup] and it has up to 80% of the global market share for rennet.[sup][7][/sup]
By 2008, approximately 80% to 90% of commercially made cheeses in the US and Britain were made using FPC.[sup][1][/sup] Today, the most widely used Fermentation-Produced Chymosin (FPC) is produced either by the fungus
Aspergillus niger and commercialized under the trademark CHY-MAX®[sup][8][/sup] by the Danish company Chr. Hansen, or produced by
Kluyveromyces lactis and commercialized under the trademark MAXIREN®[sup][9][/sup] by the Dutch company DSM.
FPC is chymosin B, and is therefore more pure compared with animal rennet, which contains a multitude of proteins. FPC can deliver several benefits to the cheese producer compared with animal or microbial rennet, such as higher production yield, better curd texture and reduced bitterness.[sup][5][/sup]
Cheeses produced with FPC can be certified kosher[sup][10][/sup][sup][11][/sup] and halal,[sup][11][/sup] and are suitable for vegetarians if there was no animal-based alimentation used during the chymosin production in the fermenter.