Lactic acid fermentation
Heterolactic fermentation, by contrast, yields carbon dioxide and ethanol in addition to lactic acid, in a process called the phosphoketolase pathway.
[1] Chemical analysis of archaeological finds show that milk fermentation had been used since prehistory; its first applications were probably a part of the Neolithic Revolution.
Since milk naturally contains lactic acid bacteria, the discovery of the fermentation process was quite evident, since it happens spontaneously at an adequate temperature.
In fact, lactic acid bacteria contain the needed enzymes to digest lactose, and their populations multiply strongly during the fermentation.
This process was also discovered a very long time ago, which is proven by recipes for cheese production on Cuneiform scripts, the first written documents that exist, and later in Babylonian and Egyptian texts.
This theory suggests that the women of these first settled agricultural civilisations could shorten the time between two children thanks to the additional lactose uptake from milk consumption.
This early habituation to lactose consumption in the first settler societies can still be observed today in regional differences of this mutation's concentration.
[5] Since these first societies came from regions around eastern Turkey to central Europe, the gene appears more frequently there and in North America, as it was settled by Europeans.
Very important with often a traditional meaning as well are fermentation products of mare milk, like for example the slightly-alcoholic yogurt kumis.
Consuming white food in this festive context is a way to connect to the past and to a national identity, which is the Mongolian empire personified by Genghis Khan.
During the time of this empire, the fermented mare milk was the drink to honor and thank warriors and leading persons, it was not meant for everybody.
[6] Although this chemical process had been used in food production for thousand of years, microbial lactic acid fermentation was not properly described before much later.
One of these was the French chemist Joseph Louis Gay-Lussac, who was especially interested in fermentation processes, and he passed this fascination to one of his best students, Justus von Liebig.
Per chance and with the badly equipped laboratory he had at that time, he was able to discover that in this distillery, two fermentations were taking place, a lactic acid one and an alcoholic one, both induced by microorganisms.
He then continued the research on these discoveries in Paris, where he also published his theories that presented a stable contradiction to the purely chemical version represented by Liebig and his followers.
Although Pasteur didn't find every detail of this process, he still discovered the main mechanism of how microbial lactic acid fermentation works.
[7][8] Homofermentative bacteria convert glucose to two molecules of lactate and use this reaction to perform substrate-level phosphorylation to make two molecules of ATP: Heterofermentative bacteria produce less lactate and less ATP, but produce several other end products: Examples include Leuconostoc mesenteroides, Lactobacillus bifermentous, and Leuconostoc lactis.
Examples of these dishes include burong isda of the Philippines; narezushi of Japan; and pla ra of Thailand.
[20] During the 1990s, the lactic acid hypothesis was created to explain why people experienced burning or muscle cramps that occurred during and after intense exercise.
Lactic acid created as a byproduct of fermentation of pyruvate from glycolysis accumulates in muscles causing a burning sensation and cramps.
Lactic acid producing bacteria also act as a protective barrier against possible pathogens such as bacterial vaginosis and vaginitis species, different fungi, and protozoa through the production of hydrogen peroxide, and antibacterial compounds.
