|
''Lactobacillus delbrueckii'' subsp. ''bulgaricus'' (until 2014 known as ''Lactobacillus bulgaricus'') is one of several bacteria used for the production of yogurt. It is also found in other naturally fermented products. First identified in 1905 by the Bulgarian doctor Stamen Grigorov, the bacterium feeds on lactose to produce lactic acid, which is used to preserve milk. It is a gram-positive rod that may appear long and filamentous. It is non-motile and does not form spores. It is regarded as aciduric or acidophilic, since it requires a low pH (around 5.4–4.6) to grow effectively. The bacterium has complex nutritional requirements. ==Use in industry== ''Lactobacillus delbrueckii ''subsp.'' bulgaricus'' is commonly used alongside ''Streptococcus thermophilus'' as a starter for making yogurt. The two species work in synergy, with ''L. d. bulgaricus'' producing amino acids from milk proteins, which are then used by ''S. thermophilus''.〔 Both species produce lactic acid,〔 which gives yogurt its tart flavor and acts as a preservative. The resulting decrease in pH also partially coagulates the milk proteins, such as casein, resulting in yogurt's thickness.〔http://www.medicinalfoodnews.com/vol01/issue5/kalab.htm〕 While fermenting milk, ''L. d. bulgaricus'' produces acetaldehyde, one of the main yogurt aroma components.〔 Some strains of ''L. d. bulgaricus'', such as ''L. bulgaricus'' GLB44, also produce bacteriocins, which have been shown to kill undesired bacteria ''in vitro''. It is often helpful to sufferers of lactose intolerance, whose digestive systems lack the enzymes to break down lactose to simpler sugars. Some of the biggest importers of the bacterium are Japan, the USA, and the EU. It has also been considered a contaminant of beer due to its homofermentatative production of lactic acid, an off-flavor in many styles of beer. In other styles of beer, however, lactic acid bacteria can contribute to the overall appearance, aroma, taste, and/or mouthfeel, and generally produce an otherwise pleasing sourness. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lactobacillus delbrueckii subsp. bulgaricus」の詳細全文を読む スポンサード リンク
|