Soured milk

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Soured milk
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Russian and Ukrainian prostokvasha (kysliak), traditional fermented milk
Main ingredients Milk

Soured milk denotes a range of food products produced by the acidification of milk. Acidification, which gives the milk a tart taste, is achieved either through bacterial fermentation or through the addition of an acid, such as lemon juice or vinegar. The acid causes milk to coagulate and thicken, inhibiting the growth of harmful bacteria and improving the product's shelf life. It is not good for making cheese.

Contents

Soured milk that is produced by bacterial fermentation is more specifically called fermented milk or cultured milk . [1] Traditionally, soured milk was simply fresh milk that was left to ferment and sour by keeping it in a warm place for a day, often near a stove. Modern commercial soured milk may differ from milk that has become sour naturally. [2] [ full citation needed ]

Soured milk that is produced by the addition of an acid, with or without the addition of microbial organisms, is more specifically called acidified milk. [1] In the United States, acids used to manufacture acidified milk include acetic acid (commonly found in vinegar), adipic acid, citric acid (commonly found in lemon juice), fumaric acid, glucono-delta-lactone, hydrochloric acid, lactic acid, malic acid, phosphoric acid, succinic acid, and tartaric acid.

Soured milk is commonly made at home or is sold and consumed in Eastern Europe, the Balkans and Scandinavia.

It is also made at home or sold in supermarkets and consumed in the Great Lakes region of Somalia and Eastern Africa (Kenya, Uganda, Rwanda, Burundi and Tanzania). It is also a traditional food of the Bantu people of Southern Africa.

Since the 1970s, some producers have used chemical acidification in place of biological agents. [3] [4] [5] [6]

In recipes

Raw milk that has not gone sour is sometimes referred to as "sweet milk", because it contains the sugar lactose. Fermentation converts the lactose to lactic acid, which has a sour flavor. Before the invention of refrigeration, raw milk commonly became sour before it could be consumed, and various recipes incorporate such leftover milk as an ingredient. Sour milk produced by fermentation differs in flavor from that produced by acidification, because the acids commonly added in commercial manufacture have different flavors from lactic acid, and also because fermentation can introduce new flavors. Buttermilk is a common modern substitute for naturally soured milk.

See also

Related Research Articles

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<span class="mw-page-title-main">Rennet</span> Complex of enzymes from the stomachs of young ruminant mammals, used in the production of cheese

Rennet is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease enzyme that curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a lipase.

<span class="mw-page-title-main">Yogurt</span> Food produced by bacterial fermentation of milk

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<span class="mw-page-title-main">Lactic acid fermentation</span> Series of interconnected biochemical reactions

Lactic acid fermentation is a metabolic process by which glucose or other six-carbon sugars are converted into cellular energy and the metabolite lactate, which is lactic acid in solution. It is an anaerobic fermentation reaction that occurs in some bacteria and animal cells, such as muscle cells.

<span class="mw-page-title-main">Cottage cheese</span> Type of cheese

Cottage cheese is a curdled milk product with a mild flavor and a creamy, heterogeneous, soupy texture. It is made from skimmed milk by draining curds but retaining some of the whey and keeping the curds loose. An essential step in the manufacturing process distinguishing cottage cheese from other fresh cheeses is the addition of a "dressing" to the curd grains, usually cream, which is mainly responsible for the taste of the product. Cottage cheese is not aged.

<span class="mw-page-title-main">Curd</span> Result of curdling milk

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<span class="mw-page-title-main">Buttermilk</span> Fermented dairy drink

Buttermilk is a fermented dairy drink. Traditionally, it was the liquid left behind after churning butter out of cultured cream. As most modern butter in western countries is not made with cultured cream but uncultured sweet cream, most modern buttermilk in western countries is cultured separately. It is common in warm climates where unrefrigerated milk sours quickly.

<span class="mw-page-title-main">Cheesemaking</span> Craft of making cheese

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Skyr is a traditional Icelandic cultured dairy product. It has the consistency of strained yogurt, but a milder flavor. Skyr can be classified as a fresh sour milk cheese, similar to curd cheese consumed like a yogurt in the Baltic states, the Low Countries, Germany and Russia. It has been a part of Icelandic cuisine for centuries.

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<span class="mw-page-title-main">Souring</span> Food technique, exposure to acid

Souring is a food preparation technique that causes a physical and chemical change in food by exposing it to an acid. This acid can be added explicitly, or can be produced within the food itself by a microbe, such as Lactobacillus.

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Kefir is a fermented milk drink similar to a thin yogurt or ayran that is made from kefir grains, a specific type of mesophilic symbiotic culture. It is prepared by inoculating the milk of cows, goats, or sheep with kefir grains.

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">Naem (food)</span> Thai fermented meat product

Naem is a pork sausage in Lao and Thai cuisine. It is a fermented food that has a sour flavor. It has a short shelf life, and is often eaten in raw form after the fermentation process has occurred. It is a popular Southeast Asian food, and different regions of Southeast Asia have various preferred flavors, including variations of sour and spicy. Naem is used as an ingredient in various dishes and is also served as a side dish.

<span class="mw-page-title-main">Sour cream</span> Fermented dairy product

Sour cream is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name comes from the production of lactic acid by bacterial fermentation, which is called souring. Crème fraîche is one type of sour cream with a high fat content and less sour taste.

<span class="mw-page-title-main">Industrial microbiology</span>

Industrial microbiology is a branch of biotechnology that applies microbial sciences to create industrial products in mass quantities, often using microbial cell factories. There are multiple ways to manipulate a microorganism in order to increase maximum product yields. Introduction of mutations into an organism may be accomplished by introducing them to mutagens. Another way to increase production is by gene amplification, this is done by the use of plasmids, and vectors. The plasmids and/ or vectors are used to incorporate multiple copies of a specific gene that would allow more enzymes to be produced that eventually cause more product yield. The manipulation of organisms in order to yield a specific product has many applications to the real world like the production of some antibiotics, vitamins, enzymes, amino acids, solvents, alcohol and daily products. Microorganisms play a big role in the industry, with multiple ways to be used. Medicinally, microbes can be used for creating antibiotics in order to treat infection. Microbes can also be used for the food industry as well. Microbes are very useful in creating some of the mass produced products that are consumed by people. The chemical industry also uses microorganisms in order to synthesize amino acids and organic solvents. Microbes can also be used in an agricultural application for use as a biopesticide instead of using dangerous chemicals and or inoculants to help plant proliferation.

Leuconostoc lactis is a species of lactic acid bacteria that performs fermentation in acidic conditions, like those found in dairy products such as cheese and yogurt, and tend to culture best at moderate temperatures around 30°C. L. lactis typically produces volatile butter-like compounds that are typically used in fermented dairy products, as well as dextran-like exopolysaccharide in sourdough.

References

  1. 1 2 "TITLE 21--FOOD AND DRUGS: CHAPTER I, PART 131 MILK AND CREAM". Electronic Code of Federal Regulations (e-CFR). 2007-04-01. Retrieved 2007-11-18.[ permanent dead link ]
  2. "Dairy-Milk" . Retrieved 2014-03-01.
  3. Nakamura, Yasunori; Yamamoto, Naoyuki; Sakai, Kumi; Takano, Toshiaki (June 1, 1995). "Antihypertensive Effect of Sour Milk and Peptides Isolated from It That are Inhibitors to Angiotensin I-Converting Enzyme". Journal of Dairy Science . 78 (6): 1253–7. doi: 10.3168/jds.S0022-0302(95)76745-5 . PMID   7673515 . Retrieved 2007-06-30.
  4. Sukhov, SV; Kalamkarova, LI; Il'chenko, LA; Zhangabylov, AK (1986). "Microfloral changes in the small and large intestines of chronic enteritis patients on diet therapy including sour milk products". Voprosy pitaniia (in Russian). Jul–Aug (4): 14–7. PMID   3765530.
  5. USpatent 3625702,Exler, Heinrich,"PREPARATION OF SOUR MILK DRINKS",published 1971-12-07,issued 1971-12-07, assigned to Heinrich Exler
  6. USpatent 3978243,Pedersen, Jens Kristian,"Process for preparing gelled sour milk",published 1976-08-31,issued 1976-08-31, assigned to Kobenhavns Pektinfabrik