Classification, basic characteristics, fermentation types and metabolites of lactic acid bacteria

"Span style"line-height: 1.5;"Fermentation is an ancient, traditional method of food storage and processing, and any food produced using the action of microorganisms can be called fermented foodFermented food is a kind of food that human beings skillfully use beneficial microorganisms to process and manufacture, which has unique flavor and nutritional value and enriches our diet lifespan style"line-height: 1.5;"Lactobacillus is one of the most important beneficial microorganisms in fermented foods, and the application of lactic acid bacteria has a long history, and in ancient times humans unconsciously used lactic acid bacteria in brewing foodHowever, human beings can take the initiative to study and master the law of life of lactic acid bacteria, and its application, or nearly a hundred yearsspan style"line-height: 1.5; "span style"line-height: 1.5;" lactic acid bacterialactic acid bacteria is the general name of a group of sugar-based lactic acid-based bacteria, lactic acid bacteria is not a taxonatiable noun, belong to the true bacteria (Eubacteriac) real bacteria (Eailles) lactic acid bacteria (eagills)In Berger's bacterial taxonomics, lactic acid bacteria have been found in at least 19 genus of the Lactobacillus genus, Strptococcus, Leuconostoc, and LactococcusAmong them, in food, medicine and other fields of more applications of Lactic acid bacteria are mainly distributed in the GenOr Lactobacillus, Bifidobacteria genus, Streptococcus genus, enterococcus genus, Lactobacillus genus, ccoccal genus and Cytobacteria genus and other seven genusthe basic characteristics of lactic acid bacterialactic acid bacteria is Gram-positive, do not form spores (except individualgens), do not exercise or less exercise, not resistant to high temperatures, but acid-resistant bacteria or bacillus, lactic acid bacteria is a combination of anaerobic bacteria, suitable for low oxygen content or oxygen-free environment growthCompared with other bacteria, lactic acid bacteria on the nutritional requirements are more stringent, in addition to the supply of appropriate amounts of water, adequate carbon sources, nitrogen sources and inorganic salts, but also need to add vitamins, amino acids and other growth factorsLactic acid bacteria can ferment certain sugars to produce lactic acid, but the ability to break down proteins and fat is weak, hydrogen peroxide reaction is negative, suitable for growth in the acid-biased environment, can make the medium pH to below 5.0, acid production and acid resistance are strongthe fermentation type of lactic acid bacteriathe fermentation of lactic acid bacteria according to the product, divided into three types: the same type of lactic acid fermentation, the fermentation of the other type lactic acid and the fermentation of double-differenceThe same type of lactic acid fermentation refers to the fermentation process of lactic acid, which is more than 90% of the final product of fermentation, mainly lactic acid streptococcus and most LactobacillusSpecific lactic acid fermentation refers to the fermentation of the final product of fermentation in addition to lactic acid, there are ethanol, carbon dioxide and other components of lactic acid fermentation process, to the lactic acid genus of the cyllascoccal genus and certain Lactobacillus lactic acid, such as enterocosis, lactobacillus, glycobacillus, and so onBifidofermentation is the production capacity model of Bifidobacteria, Bifidobacteria is a special type of strict anaerobic bacteria, high nutritional requirements, their glucose metabolism can also be classified as special lactic acid fermentation, but with other lactic acid bacteria of the other specific fermentation is different lactic acid bacteria metabolites lactic acid bacteria fermentation metabolites are mainly organic acids, bacteriogens, acetaldehyde and other aromatic substances, extracellular polysaccharides, gamma-aminobutyric acid and so on Organic acids are mainly lactic acid, acetic acid, and a small amount of aric acid, proacetic acid, etc., with antibacterial anti-corrosion effect, and bring the taste of food acidic; Fermentation food with acid bacteria brings unique fermentation flavor, extracellular polysaccharides as an important part of life matter, widely involved in the regulation of various life phenomena and physiological processes of cells, gamma-aminobutyric acid is an important inhibitory neurotransmitter in the nervous system, has the improvement of brain function, regulate emotional anti-anxiety, reduce blood pressure and other aspects of play an important role