Yoghurt, yogurt, yoghourt, youghurt or yogourt (see spelling below), is a dairy product produced by bacterial fermentation of milk. Fermentation of the milk sugar (lactose) produces lactic acid, which acts on milk protein to give yoghurt its texture and its characteristic tang. Soy yogurt, a dairy yoghurt alternative, is made from soy milk.
The word is derived from Turkish yoğurt, and is related to yoğurmak 'to knead' and yoğun 'dense' or 'thick'.. The letter ğ was traditionally rendered as "gh" in transliterations of Turkish, which used to be written in a variant of the Arabic alphabet until the introduction of the Latin alphabet in 1928. In older Turkish the letter denoted a voiced velar fricative /ɣ/, but this sound is elided between back vowels in modern Turkish, in which the word is . Some eastern dialects retain the consonant in this position, and Turks in the Balkans pronounce the word with a hard /g/.
In English, there are several variations of the spelling of the word. In the United States, yogurt is the usual spelling and yoghurt a minor variant. In the United Kingdom, yoghurt and yogurt are both current, yoghurt being more common, and yoghourt is an uncommon alternative. Canada uses mostly yogurt and yogourt, the latter being particularly common in bilingual packaging, as it is also the spelling in Canadian French; in Australia and New Zealand yoghurt prevails. Whatever the spelling, the word is pronounced with a short "o" in the UK, a long or short "o" in New Zealand, and with a long "o" in North America, Ireland and Australia (UK or /'jəʊgət/; North America /'joʊgɚt/; Australia /'jəʉgət/).
Whatever the spelling, the word is pronounced with a short "o" in the UK, a long or short "o" in New Zealand, and with a long "o" in North America, Ireland and Australia (UK or /'jəʊgət/; North America /'joʊgɚt/; Australia /'jəʉgət/).
There is evidence of cultured milk products being produced as food for at least 4,500 years. The earliest yoghurts were probably spontaneously fermented by wild bacteria living on the goat skin bags carried by nomadic people. Today, many different countries claim yoghurt as their own invention, yet there is no clear evidence as to where it was first discovered.
The use of yoghurt by mediaeval Turks is recorded in the books Diwan Lughat al-Turk by Mahmud Kashgari and Kutadgu Bilig by Yusuf Has Hajib written in the eleventh century. In both texts the word "yoghurt" is mentioned in different sections and its use by nomadic Turks is described. The first account of a European encounter with yoghurt occurs in French clinical history: Francis I suffered from a severe diarrhea which no French doctor could cure. His ally Suleiman the Magnificent sent a doctor, who allegedly cured the patient with yoghurt.
Until the 1900s, yoghurt was a staple in diets of the South Asian, Central Asian, Western Asian, South Eastern European and Central European regions. The Russian biologist Ilya Ilyich Mechnikov had an unproven hypothesis that regular consumption of yoghurt was responsible for the unusually long lifespans of Bulgarian peasants. Believing Lactobacillus to be essential for good health, Mechnikov worked to popularise yoghurt as a foodstuff throughout Europe. It fell to a Sephardic Jewish entrepreneur named Isaac Carasso to industrialise the production of yoghurt. In 1919, Carasso, who was from Salonika, started a small yoghurt business in Barcelona and named the business Danone ("little Daniel") after his son. The brand later expanded to the United States under an Americanised version of the name: Dannon. Yoghurt with added fruit jam was invented to protect yoghurt from decay. It was patented in 1933 by the Radlická Mlékárna dairy in Prague, and introduced to the United States in 1947, by Dannon.
Yoghurt was first introduced to the United States by Armenian immigrants Sarkis and Rose Colombosian, who started "Colombo and Sons Creamery" in Andover, Massachusetts in 1929. Colombo Yogurt was originally delivered around New England in a horse-drawn wagon inscribed with the Armenian word "madzoon" which was later changed to "yogurt", the Turkish name of the product, as Turkish was the lingua franca between immigrants of the various Near Eastern ethnicities who were the main consumers at that time. Yoghurt's popularity in the United States was enhanced in the 1950s and 60's when it was presented as a health food. By the late 20th century yoghurt had become a common American food item and Colombo Yogurt was sold to General Mills in 1993.
Yoghurt is made by introducing specific bacteria strains into milk, which is subsequently fermented under controlled temperatures and environmental conditions (inside a bioreactor), especially in industrial production. The bacteria ingest natural milk sugars and release lactic acid as a waste product. The increased acidity causes milk proteins to tangle into a solid mass (curd) in a process called denaturation. The increased acidity (pH=4–5) also prevents the proliferation of potentially pathogenic bacteria. In the U.S., to be named yogurt, the product must be made with the bacterial species Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Often these two are co-cultured with other lactic acid bacteria for taste or health effects (See probiotics). These include L. acidophilus, L. casei and Bifidobacterium species. In most countries, a product may be called yoghurt only if live bacteria are present in the final product. In the U.S., non-pasteurised yoghurt can be marketed as "live" or containing "live active culture". A small amount of live yoghurt can be used to inoculate a new batch of yoghurt, as the bacteria reproduce and multiply during fermentation. Pasteurised products, which have no living bacteria, are called fermented milk (drink). When yoghurt is pasteurised, even though its main aim is to kill harmful bacteria, it kills large amounts of essential bacteria too, such as Acidophilus, Bifidus and Lactobacillus Rhamnosus (LGG).
Yoghurt has nutritional benefits beyond those of milk: people who are moderately lactose-intolerant can enjoy yoghurt without ill effects, because the lactose in the milk precursor is converted to lactic acid by the bacterial culture. The reduction of lactose bypasses the affected individuals' need to process the milk sugar themselves.
Yoghurt also has medical uses, in particular for a variety of gastrointestinal conditions, and in preventing antibiotic-associated diarrhea. One study suggests that eating yoghurt containing L. acidophilus helps prevent vulvovaginal candidiasis, though the evidence is not conclusive.
Yoghurt is believed to promote good gum health, possibly because of the probiotic effect of lactic acids present in yoghurt.
To offset its natural sourness, yoghurt can be sold sweetened, flavored, or in containers with fruit or fruit jam on the bottom. If the fruit has been stirred into the yoghurt before purchase, it is commonly referred to as Swiss-style. Most yoghurts in the United States have added pectin or gelatin. Some specialty yoghurts have a layer of fermented fat at the top. Fruit jam is used instead of raw fruit pieces in fruit yoghurts to allow storage for weeks. "Strained" yoghurt is the concentrated residue (described as a sort of "yoghurt cheese") produced by filtering plain yoghurt that is without flavorings, gelatin, pectin, or other additives through a paper or cloth filter, and allowing water and whey to drain away. "Strained" yoghurt is available commercially under the descriptor "Greek-style"
Dahi is a yoghurt of the Indian subcontinent, known for its characteristic taste and consistency. Dahi word seems to be derived from Sanskrit word Dhadhi .Dhadhi is one of the five elixirs (Panchamruth) namely Yogurt, Milk, Honey, Ghee (clarified butter), Sugarcane juice which are used by mixing them in sacred rituals normally to bath the idols and fire rituals.
It is also found in different flavours, out of which 2 are famous: 1) sour curd - tauk doi 2) sweet curd - meesti or podi doi. According to Hindi (देवनागरी लिपि) it is considered to be feminine in nature. In India it is specially used as cosmetics filling with turmeric and honey. Sour curd (खट्टी दही) is also used as hair conditioner by women in northern parts of India.
Yoghurt is customarily made in domestic environments in regions where yoghurt has an important place in traditional cuisine. It can be made by scalding milk, cooling it to just above body temperature, and then adding either live culture or a small amount of previously made yoghurt (for example, store-bought, plain, live-culture yoghurt). The scalding of the milk is done by any kitchen appliance (eg hot plate, microwave, ...) and the cooling is usually done by means of a refrigerator. The mixture is then kept at the warm temperature (41-49°Celsius) for several hours (usually some 8-14 hours), during which fermentation (proliferation of the bacteria that were in the previously made yoghurt) causes it to become yoghurt.To maintain the milk with yeast at this warm temperature, cooking thermometers and ovens (or yoghurt-makers) are usually used. An alternative is the use of a thermos , special yoghurt-making machines (to make larger quantities of yogurt) or even microwaves In addition, some nonfat-dry milk may be added to thicken the end product and if one wishes to increase the nutritional content of the yoghurt (this is added before the yeast culture or active yoghurt is added to the milk).