Fermentation
Edible Exhibit: The Taste of Things To Come
* The Naughton Institute / Science Center *
* Trinity College * Pearse Street * Dublin 2 Ireland *
* http://www.dublinscience2012.ie/2012/02/edible/ * February 10 – April 5, 2012 *
Fermentation
One of the most brilliant natural processes, fermentation is the heart of indulgence, addiction, altered states, cooking, and chemistry. The word comes from the latin “fervere” meaning “to boil” and thought to have come from the science of alchemy in the late 14th century, though not used in modern science until the 1600′s. In food production, it is the conversion of carbohydrates into alcohols, carbon dioxide, and organic acids utilizing yeasts and/or bacteria under anaerobic conditions which is simply put “converting sugar into ethanol”. The process is so brilliant, there is a science totally dedicated to it called zymurgy or zymology. Converting sugars and carbohydrates led to transforming juice into wine, grain into beer, vegetable sugars into preservative organic acids, and carbohydrates into CO2 to leaven bread. In the liquor cabinet, it is used to create cider, mead, grappa, sake, beer, and wine. In the food cabinet, it is utilized for the leavening of bread, creating vinegar, yogurt, sauerkraut, pickling, kimchi, and preservation of some meats. Some popular fermented by-products are alcohol; amazake; asinan; atchara; bai-ming; belacan; burong mangga; bread; cheese; chiraki; com ruou; cultured milk; chicha; dalok; doenjang; douchi; elderberry wine; fermented millet porridge; garri; hibiscus seed; hot pepper sauce; injera; jeruk; lambanog; kefir; kimchi; kombucha; kumis (mare milk); leppet-so; miang; miso; nata de coco; nata de pina; nato; lupin seed; oilseed; chocolate; vanilla; naw-mai-dong; narezushi; Nattō (Japanese soybean food); oncom; pak-siam-dong; paw-tsaynob; prahok; pickling; ruou nep; sake; sauerkraut; seokbakji; shubat (camel milk); soju; sourdough bread; soy sauce; stinky tofu; tabasco; pulque; szechwan cabbage; tai-tan tsoi; tape; tempeh; totkal kimchi; wine; yogurt; yen tsai; zha caivinegar; salami; prosciuto; quark; poi; sago; and many others.
It is an ancient technology, preceding human history, as it naturally occurs in nature. One of the earliest recorded uses of it by humans was found in the Zagros Mountains of Iran, where 7,000 year old jars were found containing “wine”. Archaeological finds of Beer fermented in Ancient Egypt as early as 3,150 BCE and Babylon in 3,000 BCE. The first recorded evidence of the living nature of yeast comes from three publications appearing between 1837-1838 where Cagniard de la Tour, T. Swann, and F. Kuetzing concluded it was a result of microscopic investigations that yeast was a living organism that reproduced by budding. In the 1870′s it was a common term especially in connection with baceria and largely connected with studies of diseases and germs. The world’s first zymologist, was the chemist “Louis Pasteur” who made the connection that yeast was involved in fermentation and labelled the process as “respiration without air”. He theorized that the fermentation of sugar to alcohol by yeast was catalyzed by a vita force called “ferments” that existed within the yeast cells. He originally believed them to funcion only within living organisms and hypothesized that “alcoholic fermentation” was an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. The truth however, yeast extracts can ferment sugar even in the absence of living yeast cells. This was proved in 1897 by Eduard Buchner who found hat sugar was fermented even when there was no living yeast cells in the mix by a yeast secretion called “zymase”. His theory led him to receive the Nobel Prize in Chemistry for his research and discovery of “cell-free fermentation” in 1907 as well as the discovery of NAD+. The benefits of this process is 5-fold, in that it (1) enriches the diet with a variety of flavors, textures, and aromas in food substrates; (2) preserves large quantities of food through alcohol, lactic acid, acetic acid, and alkaline fermentations; (3) biologically enriches food substrates with essential amino acids, protein, fatty acids, and vitamins; (4) Eliminates anti-nutrients; and (5) Decreases fuel requirements and cooking times in food preparation.
It has however been involved in cases of botulism, especially in Alaska which is caused by a process of fermentation used by the Eskimo allowing animal products such as walrus, sea lion, whale flippers, beaver tales, whole fish, fish heads, seal oil, and birds to ferment for an extended period of time before eating them. In the modern era, this is intensified by the use of plastic containers in the process instead of the tradition grass-lined holes as the botulinum bacteria thrives in the anaerobic conditions created by air-tight enclosures such as plastics.
Fermentation is also used popularly in bio-chemistry, creation of fuels, industry, bio-chemicals, and chemistry. It can be used to create more exotic compounds such as butyric acid and acetone. It naturally occurs in mammalian muscle structures during periods of intense exercise when oxygen supply is limited and thereby creates lactic acid. The Chemical Formula for Ethanol is C2H5OH (C6H12O6 → 2 C2H5OH + 2 CO2). Hydrogen Gas is also produced in many forms of fermentation, especially mixed acid, butyric acid, caproate, butanol, and glyoxylate fermentations which regenerates NAD+ from NADH.
Bibliography/Recommended Reading:
Edible Exhibit: The Taste of Things To Come
* The Naughton Institute / Science Center *
* Trinity College * Pearse Street * Dublin 2 Ireland *
* http://www.dublinscience2012.ie/2012/02/edible/ * February 10 – April 5, 2012 *
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