Zymology

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Beer fermenting at a brewery Wye Valley fermenter.jpg
Beer fermenting at a brewery

Zymology, also known as zymurgy, [lower-alpha 1] is an applied science that studies the biochemical process of fermentation and its practical uses. Common topics include the selection of fermenting yeast and bacteria species and their use in brewing, wine making, fermenting milk, and the making of other fermented foods.

Contents

Fermentation

Fermentation can be simply defined, in the context of brewing, as the conversion of sugar molecules into ethanol and carbon dioxide by yeast.

Fermentation practices have led to the discovery of ample microbial and antimicrobial cultures on fermented foods and products. [1] [2]

History

French chemist Louis Pasteur was the first 'zymologist' when in 1857 he connected yeast to fermentation. Pasteur originally defined fermentation as "respiration without air".

Pasteur performed careful research and concluded:

Je pense que la fermentation alcoolique ne se produit jamais sans une organization simultanée, une développement, une multiplication de cellules … . Si l'on me demandai en quoi consiste la réaction chimique par laquelle le sucre et décomposé … je l'ignore complètement.

I am of the opinion that alcoholic fermentation never occurs without simultaneous organization, development and multiplication of cells … . If asked, in what consists the chemical act whereby the sugar is decomposed … I am completely ignorant of it.

La Fermentation Alcoolique [3]

The German Eduard Buchner, winner of the 1907 Nobel Prize in chemistry, later determined that fermentation was actually caused by a yeast secretion, which he termed 'zymase'.

The research efforts undertaken by the Danish Carlsberg scientists greatly accelerated understanding of yeast and brewing. The Carlsberg scientists are generally acknowledged[ by whom? ] as having jump-started the entire field of molecular biology.

Products

Notes

  1. From the Ancient Greek: ζύμωσις + ἔργον, "the workings of fermentation".

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<span class="mw-page-title-main">SCOBY</span> Symbiotic culture of bacteria and yeast

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The role of yeast in winemaking is the most important element that distinguishes wine from fruit juice. In the absence of oxygen, yeast converts the sugars of the fruit into alcohol and carbon dioxide through the process of fermentation. The more sugars in the grapes, the higher the potential alcohol level of the wine if the yeast are allowed to carry out fermentation to dryness. Sometimes winemakers will stop fermentation early in order to leave some residual sugars and sweetness in the wine such as with dessert wines. This can be achieved by dropping fermentation temperatures to the point where the yeast are inactive, sterile filtering the wine to remove the yeast or fortification with brandy or neutral spirits to kill off the yeast cells. If fermentation is unintentionally stopped, such as when the yeasts become exhausted of available nutrients and the wine has not yet reached dryness, this is considered a stuck fermentation.

Microbial food cultures are live bacteria, yeasts or moulds used in food production. Microbial food cultures carry out the fermentation process in foodstuffs. Used by humans since the Neolithic period fermentation helps to preserve perishable foods and to improve their nutritional and organoleptic qualities. As of 1995, fermented food represented between one quarter and one third of food consumed in Central Europe. More than 260 different species of microbial food culture are identified and described for their beneficial use in fermented food products globally, showing the importance of their use.

Symbiotic fermentation is a form of fermentation in which multiple organisms interact in symbiosis in order to produce the desired product. For example, a yeast may produce ethanol, which is then consumed by an acetic acid bacterium. Described early on as the fermentation of sugars following saccharification in a mixed fermentation process.

<span class="mw-page-title-main">Corn sauce</span>

Corn sauce or fermented corn sauce is produced by fermentation using corn starch as the primary substrate. It is used as a food condiment and ingredient, both in paste and in powder form. Corn sauce, like soy sauce, has a characteristic savory taste. It is used to flavor dishes including soups, broths, and gravies.

References

  1. Sreeramulu, Zhu & Knol (2000).
  2. Demain, Martens & Knol (2017).
  3. Harden, Arthur (1913). La Fermentation Alcoolique (in French). A. Hermann. pp. 15–16.

Sources