Yoghurt

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Yoghurt

Yoghurt or yogurt, less commonly yoghourt or yogourt, is a dairy product produced by bacterial fermentation of milk. Any sort of milk may be used to make yoghurt, but modern production is dominated by cow's milk. It is the fermentation of milk sugar (lactose) into lactic acid that gives yoghurt its gel-like texture and characteristic tang.

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History

Yoghurt is traditionally believed to be an invention of the Bulgars of central Asia, although there is evidence of cultured milk products in other cultures 4500 years ago. The earliest yoghurts were probably spontaneously fermented, perhaps by wild bacteria residing inside goatskin bags used for transportation.

The word derives from the Turkish yoğurt (pronounced ) deriving from the verb yoğurmak, which means "to blend", a reference to how yoghurt is made. The letter ğ is silent between back vowels in Modern Turkish, but was formerly pronounced as a voiced velar fricative . English pronunciation varies in different regions according to the local accent but common pronunciations include and .

Yoghurt remained primarily a food of India, Central Asia, the Levant region of the Middle East, South Eastern Europe and Central Europe until the 1900s, when a Russian biologist named Ilya Ilyich Mechnikov theorized that heavy consumption of yoghurt was responsible for the unusually long lifespans of the Bulgar people. Believing lactobacillus to be essential for good health, Mechnikov worked to popularize yoghurt as a foodstuff throughout Europe. It fell to a Spanish entrepreneur named Isaac Carasso to industrialise the production of yoghurt. In 1919 he started a commercial yoghurt plant in Barcelona, naming the business Danone after his son — the group trades as Dannon in the US.

Yoghurt with added fruit marmalade was invented (and patented) in 1933 in dairy Radlicka Mlekarna in Prague. The original intention of this combination was to protect yoghurt better against decay.

Yoghurt was first commercially produced and sold in the United States in 1929 by Armenian immigrants, Rose and Sarkis Colombosian, whose family business later became Colombo Yogurt.

Yoghurt making involves the introduction of specific "friendly" bacteria into preferably unpasteurised, unhomogenised milk (to maintain the healthy balance of bacteria and enzymes of milk in its unprocessed state) under very carefully controlled temperature and environmental conditions. The bacteria ingest the natural milk sugars and release lactic acid as a waste product; the increased acidity, in turn, causes the milk proteins to tangle into a solid mass, (curd). Generally a culture includes two or more different bacteria for more complete fermentation, most commonly Streptococcus salivarius and thermophilus, and Lactobacillus genus members, such as L. acidophilus, bulgaricus and bifidus.

If the yoghurt is not heated to kill the bacteria after fermentation it is sold as containing "live active culture" (or just as "live" in some countries), which some believe to be nutritionally superior. In Spain, the yoghurt producers were divided among those who wanted to reserve the name yogur for live yoghurt and those who wanted to include pasteurised yoghurt under that label (mostly the Pascual Hermanos group). Pasteurised yoghurt has a shelf life of months and does not require refrigeration. Both sides submitted scientific studies claiming differences or their lack between both varieties. Eventually the Spanish government allowed the label yogur pasteurizado instead of the former postre lácteo ("dairy dessert").

Because live yoghurt culture contains enzymes that break down lactose, some individuals who are otherwise lactose intolerant find that they can enjoy yoghurt without ill effects. Nutritionally, yoghurt is rich in protein as well as several B vitamins and essential minerals, and it is as low or high in fat as the milk it is made from.

Presentation

Bulgarian yoghurt is popular for its specific taste, aroma, and quality and is commonly consumed plain. The qualities are specific to the particular culture strains used in Bulgaria, Lactobacillus bulgaricus and Streptococcus thermophilus bacteria. Bulgarian yoghurt producers are taking steps to legally protect the trademark of Bulgarian yoghurt on the European market and distinguish it from other product types that do not contain live bacteria.

Bulgarian yoghurt is often strained by hanging in a cloth for a few hours to reduce water content. The resulting yoghurt is creamier, richer and milder in taste because of increased fat content. Hanging overnight is sometimes employed to make a concentrated yoghurt similar to cream cheese. Yoghurt is also used for preparation of Bulgarian milk salad (also known as Greek tzatziki sauce). Commercial versions of strained yoghurt are also made.

Yoghurt is often sold sweetened and flavoured, or with added fruit on the bottom (often referred to as fruit bottom, to offset its natural sourness. If the fruit is already stirred into the yoghurt, it is sometimes referred to as Swiss-style.

Greek "full" yoghurt is made from milk that has been blended with cream to a fat content of exactly ten percent. Standard (5%), low-fat (2%) and non-fat (0%) versions are also made. It is often served with honey or fruit preserves as a dessert. The Greek traditional tzatziki sauce, used on a gyros sandwich, is made from yoghurt, cucumber, and garlic.

Lassi is a yoghurt-based beverage, originally from India where two basic varieties are known: salty and sweet. Salty lassi is usually flavoured with ground-roasted cumin and chili peppers; the sweet variety with rosewater and/or lemon, mango, or other fruit juice. A lassi-like, salty drink called Ayran is also quite popular in Turkey and Bulgaria. It is made by mixing yoghurt with water and adding salt. The same drink is known as tan in Armenia.

A cold soup called tarator is popular in summertime Bulgaria. It is made from Ayran, cucumbers, garlic and nuts.

Kefir is a fermented milk drink originating in the Caucasus. Some American dairies have offered a drink called "kefir" for many years (though lacking the carbonation and alcohol, and coming in fruit flavours), but began appearing (as of 2002) with names like "drinkable yoghurt" and "yoghurt smoothie".

Home-made yoghurt

Home-made yoghurt is consumed by many people throughout the world, and is the norm in countries where yoghurt has an important place in traditional cuisine, such as Bulgaria, Turkey, and India. Yoghurt can be made at home using a small amount of store-bought plain live active culture yoghurt as the starter culture. One very simple recipe starts with a litre of low-fat milk, but requires some means to incubate the fermenting yoghurt at a constant 43°C (109°F) for several hours. Yoghurt-making machines are available for this purpose. As with all fermentation processes, cleanliness is very important.

Bring the milk to 85°C (185°F) over a stove and keep it there for two minutes, to kill any undesirable microbes.
Pour the re-pasteurised milk into a tall, sterile container and allow to cool to 43°C (110°F)
Mix in 120ml of the warmed yoghurt and cover tightly.
After about six hours of incubation at precisely 43°C (110°F); the entire mixture will have become a very plain but edible yoghurt with a loose consistency.
- If a precise means of temperature control is not available, put the culture in a warm place such as on top of a water heater or in a gas oven with just the pilot flame burning. An electric oven with the light on may work nicely, depending on the bulb size. The further below 43°C (110°F) the temperature, the longer it will take for the yoghurt to solidify; you can tell it is done when it no longer moves if you tilt the jar.