Sourdough or sourdough bread is a bread made by the fermentation of dough using wild lactobacillaceae and yeast. Lactic acid from fermentation imparts a sour taste and improves keeping qualities.
In the Encyclopedia of Food Microbiology, Michael Gaenzle writes: "One of the oldest sourdough breads dates from 3700 BCE and was excavated in Switzerland, but the origin of sourdough fermentation likely relates to the origin of agriculture in the Fertile Crescent and Egypt several thousand years earlier", which was confirmed a few years later by archeological evidence. ... "Bread production relied on the use of sourdough as a leavening agent for most of human history; the use of baker's yeast as a leavening agent dates back less than 150 years."
Sourdough remained the usual form of leavening down into the European Middle Ages until being replaced by barm from the beer brewing process, and after 1871 by purpose-cultured yeast.
Bread made from 100% rye flour, popular in the northern half of Europe, is usually leavened with sourdough. Baker's yeast is not useful as a leavening agent for rye bread, as rye does not contain enough gluten. The structure of rye bread is based primarily on the starch in the flour as well as other carbohydrates known as pentosans; however, rye amylase is active at substantially higher temperatures than wheat amylase, causing the structure of the bread to disintegrate as the starches are broken down during baking. The lowered pH of a sourdough starter, therefore, inactivates the amylases when heat cannot, allowing the carbohydrates in the bread to gel and set properly. In the southern part of Europe, where panettone is still made with sourdough as leavening, sourdough has become less common in the 20th century; it has been replaced by the faster-growing baker's yeast, sometimes supplemented with longer fermentation rests to allow for some bacterial activity to build flavor. Sourdough fermentation re-emerged as a major fermentation process in bread production during the 2010s, although it is commonly used in conjunction with baker's yeast as leavening agent.
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The course will deliver basic knowledge on the principles of food fermentation and enzyme technology. The course will also present benefits that food biotechnology can bring in terms of Nutrition & He
"Microbiology for engineers" covers the main microbial processes that take place in the environment and in treatment systems. It presents elemental cycles that are catalyzed by microorganisms and that
Lactobacillus is a genus of gram-positive, aerotolerant anaerobes or microaerophilic, rod-shaped, non-spore-forming bacteria. Until 2020, the genus Lactobacillus comprised over 260 phylogenetically, ecologically, and metabolically diverse species; a taxonomic revision of the genus assigned lactobacilli to 25 genera (see below). Lactobacillus species constitute a significant component of the human and animal microbiota at a number of body sites, such as the digestive system, and the female genital system.
In food processing, fermentation is the conversion of carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic (oxygen-free) conditions. Fermentation usually implies that the action of microorganisms is desired. The science of fermentation is known as zymology or zymurgy. The term "fermentation" sometimes refers specifically to the chemical conversion of sugars into ethanol, producing alcoholic drinks such as wine, beer, and cider.
Saccharomyces cerevisiae (ˌsɛrəˈvɪsi.iː) (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been originally isolated from the skin of grapes. It is one of the most intensively studied eukaryotic model organisms in molecular and cell biology, much like Escherichia coli as the model bacterium. It is the microorganism behind the most common type of fermentation.
Delves into the science of food fermentation, covering lactose metabolism, soy food fermentation, human milk production, kimchi making, and bacteria isolation.
The crystal structure and property changes of sodium bismuth titanate (Na0.5Bi0.5TiO3, NBT) piezoelectric ceramics are reported as a function of La modification (0.5-2.0 at. %) and increasing temperature using high resolution x-ray diffraction, permittivit ...
AimsTo monitor the effect of a live yeast additive on feedstuff colonization by targeted fibrolytic micro-organisms and fibre degradation in the cow rumen. Methods and ResultsAbundance of adhering fibrolytic bacteria and fungi on feedstuffs incubated in sa ...
Wiley-Blackwell2016
The objective of this thesis was to evaluate the feasibility for the production of fuel bioethanol from whey permeate. The identification of the limiting factors of the process revealed that the stabilization of the substrate was critical to the use of whe ...