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Yoghurt, yoğurt or yogurt, or less commonly yoghourt or yogourt (see spelling differences), is a dairy product produced by bacterial fermentation of milk. It can be mad from any milk, but modern production is dominated by cow's milk. The fermentation of milk sugar (lactose) produces lactic acid, which acts on milk protein to give yoghurt its gel-like texture and characteristic tang. Yoghurt is often sold in a fruit, vanilla, or chocolate flavour, but can be unflavoured.

History

There is evidence of cultured milk products being produced as food for at least 4,500 years, since the 3rd millennium BC. The earliest yoghurts were probably spontaneously fermented by wild bacteria living on the goatskin bags carried by the Bulgars (or Hunno-Bulgars), a nomadic people who began migrating into Europe in the 2nd century AD and eventually settled on the Balkans by the end of the 7th century.

Yoghurt remained primarily a food of India, Central Asia, Western Asia, 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 Bulgarian peasants. 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, Carasso started a commercial yoghurt plant in Barcelona, naming the business Danone after his son. It is better known in the United States as 'Dannon'.

Yoghurt with added fruit marmalade was invented to protect yoghurt better against decay. It was patented in 1933 by the Radlická Mlékárna dairy in Prague.

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.

Etymology of 'yoghurt'

The word derives from the Turkish yoğurt (pronounced ) deriving from the adjective 'yoğun', which means "dense" and "thick", or from the verb yoğurmak, which means "to knead" and possibly meant "to make dense" originally -- how yoghurt is made. The letter ğ is silent between back vowels in Modern Turkish, but was formerly pronounced as a voiced velar fricative and still retains this pronunciation in some eastern dialects. English pronunciation varies according to the local accent but common pronunciations include /ˈjɒgət/ and /ˈjoʊgɚt/.

Contents

Yoghurt is made by introducing specific bacteria into milk under controlled temperature and environmental conditions, 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, denature). The increased acidity (pH=4–5) also prevents the proliferation of potentially pathogenic bacteria. To be named yoghurt, the product must contain the bacteria Streptococcus salivarius ssp thermophilus and Lactobacillus bulgaricus (official name Lactobacillus delbrueckii ssp. bulgaricus). Often these two are co-cultured with other lactic acid bacteria for taste or health effects (probiotics). These include L. acidophilus, Lactobacillus casei and Bifidobacterium species.

In most countries, a product may be called yoghurt only if live bacteria are present in the final product. Pasteurized products, which have no living bacteria, are called fermented milk (drink).

In the U.S.A., non-pasteurized yoghurt is sold as "live" or containing "live active culture", which some believe to be nutritionally superior. In Spain, yoghurt producers were divided between those who wanted to reserve the name yogurt for live yoghurt and those who wanted to include pasteurised products, the Pascual Hermanos group being the most prominent among the latter. Pasteurized yoghurt has a shelf life of months and does not require refrigeration. Both sides submitted scientific studies supporting their claims. The Spanish government eventually allowed the label yogur pasteurizado to replace the former postre lácteo ("dairy dessert").

People who are otherwise lactose-intolerant often enjoy yoghurt without ill effects, since live yoghurt culture contains enzymes that help break down lactose inside the intestine.

Yoghurt is rich in protein, several B vitamins, and essential minerals. It contains as much fat as the milk it is made from.

For women who experience yeast infections, a common cure is the daily ingestion of yogurt containing L. acidophilus, which combats the imbalance of colonies of the fungus Candida albicans by adding more L. acidophilus. Another method to combat a yeast infection is the direct topical application of yoghurt to the affected female area since Candida species are not able to thrive in the acidic pH that topically applicated yoghurt would generally create.

Non-sweetened, drinkable yoghurt is typically sold in the West as buttermilk or cultured buttermilk. This is a misnomer, as the drink has little in common with buttermilk and is, in fact, most similar to kefir.

Presentation

To offset its natural sourness, yoghurt is often sold sweetened, flavoured, or with fruit on the bottom. If the fruit is stirred into the yoghurt, it may be referred to as Swiss-style. Most yoghurt in the United States adds pectin or gelatin. Like cream cheese, some specialty yoghurts (e.g., Brown Cow Yoghurt) 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.

Yoghurt types

Dahi yoghurt

Dahi yoghurt of the Indian subcontinent is known for its characteristic taste and consistency. The English term for a specific yoghurt in India and Pakistan is curd. A typical preparation of curd, a dessert called 'shrikhand' in India or RusMalai in Pakistan, is made with curd placed in a soft cloth with very fine holes, such as soft muslin. Tied up and hung to drain for a few hours while all the water is drained out, sugar, saffron, cardamom, diced fruit, raisins, and nuts are then mixed for taste.

Dadiah or Dadih

Dadiah or Dadih is a traditional West Sumatran yogurt made from water buffalo milk. It is fermented in bamboo tubes.

Labneh or Labaneh

Labneh yoghurt of Lebanon is a thickened yogurt used for sandwiches. Olive oil, cucumber slices, olives, and various green herbs may be added. It can be thickened further and rolled into balls, preserved in olive oil, and fermented for a few more weeks. It is sometimes used with onions, meat, and nuts as a stuffing for a variety of Lebanese pies or Kebbeh كبة balls.

Bulgarian yoghurt

Bulgarian yoghurt, commonly consumed plain, is popular for its taste, aroma, and quality. The qualities arise from the Lactobacillus bulgaricus and Streptococcus thermophilus culture strains used in Bulgaria. This yogurt is often labelled and sold as Greek yoghurt, especially in British and American markets. Bulgarian yoghurt producers are taking steps to protect the Bulgarian yoghurt trademark in Europe and to distinguish it from other products that do not contain live bacteria.

Bulgarian yoghurt is often strained by hanging it 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 it overnight creates a concentrated yoghurt similar to cream cheese. Yoghurt is also used to prepare Bulgarian milk salad. Commercial versions of strained yoghurt exist.

A popular cold soup made from yogurt is popular in the summertime in Bulgaria and Turkey. Called tarator and cacık, respectively, it is made with Ayran, cucumbers, garlic and ground walnuts.

Yoghurt Drinks

Lassi is a yoghurt-based beverage originally from Indian Subcontinent ( i.e. India, Pakistan and Bangladesh), usually made salty or sweet. Salty lassi is usually flavoured with ground-roasted cumin and chile peppers; the sweet variety with rosewater, lemon, mango or other fruit juice. Another yoghurt-based beverage, a salty drink called Ayran, is popular in Turkey, Bulgaria and Greece. It is made by mixing yoghurt with water and adding salt. The same drink is known as tan in Armenia. A similar drink, Doogh, is popular in the Middle East between Lebanon and Iran; it differs from ayran by the addition of herbs, usually mint, and is carbonated, usually with seltzer water. In the United States, yoghurt-based beverages are often marketed under names like "yogurt smoothie" or "drinkable yogurt".

Kefir

Kefir is a fermented milk drink originating in Caucasus. A related Central Asian-Turco Mongolian drink made from mare's milk is called kumis, or airag in Mongolia. Some American dairies have offered a drink called "kefir" for many years with fruit flavours but without carbonation or alcohol. As of 2002, names like "drinkable yoghurt" and "yoghurt smoothie" have been introduced.

Homemade yoghurt

Homemade yoghurt is consumed throughout the world and is the norm where yoghurt has an important place in traditional cuisine, such as Bulgaria, Iran, Turkey, Montenegro, Greece, Pakistan and India. It can be made with a small amount of store-bought plain live active culture yoghurt as the starter culture. One recipe starts with a litre of low-fat milk and requires some means of incubating the fermenting yoghurt at a constant 43°C (109°F) for several hours. Yoghurt-making machines are available for this purpose. As an alternative, a heating pad sold in pharmacies for muscle aches may be set at medium with a pot of tepid water on top. Place the milk in the pot. 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 undesirable microbes.
• Pour the re-pasteurised milk into a tall, sterile container and allow to cool to 43°C (110°F).
• Mix in 120 ml of the warmed yoghurt and cover tightly.
• After about six hours of incubation at precisely 43°C (110°F), the entire mixture becomes a very plain but edible yoghurt with a loose consistency.
  • The further below 43°C (110°F) the temperature, the longer it will take for the yoghurt to solidify. If a precise means of temperature control is not available, place 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. You may wrap a small towel around the container. An electric oven with the light on may work nicely, depending on the bulb size. It is done when it no longer moves if you tilt the jar.

In Japan, Caspian Sea Yoghurt is a very popular homemade yoghurt. It is believed to have been introduced into the country by researchers in a sample brought back from Georgia in the Caucasus region in 1986. This Georgian yogurt, called Matsoni, is mostly made up of Lactococcus lactis subsp. cremoris and Acetobacter orientalis and has a uniquely viscous, honey-like texture and is milder in taste than many other yoghurts.

Caspian Sea yoghurt is well-suited for making yoghurt at home because it require no special equipment and cultures at room temperature (20–30°C) in about 10 to 15 hours, depending on the temperature. In Japan, freeze-dried starter cultures are sold in big department stores or online, although many people obtain starter cultures from friends as well.

• General instructions: sterilise all utensils, containers and lids in boiling water prior to use.
  • Stir the freeze-dried starter in a container into about 250 ml of milk and cover it with a lid. Incubation time is approximately 12-36 hours from starter. Make the next batch as below using the actual yoghurt as the starter.
  • In the winter, use about one part yoghurt to four parts milk. In the summer, use about one part yoghurt to nine parts milk.
• Place the lid gently on top of the container so as to allow some air in, but prevent contamination. Leave in a clean dry place for 10-15 hours or until thick. This may take less than 10 hours in the summer and longer than 15 hours in the winter.
• Some thickening of the yoghurt will occur in the refrigerator.
• The yoghurt can be stored in the refrigerator for a week or longer.
• To reduce contamination, always make the next batch of yoghurt before using the current batch, and use the containers only for making yoghurt.

References

1. United States Food and Drug Administration (2024). "Daily Value on the Nutrition and Supplement Facts Labels". FDA. Archived from the original on 2024-03-27. Retrieved 2024-03-28.
2. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). "Chapter 4: Potassium: Dietary Reference Intakes for Adequacy". In Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). pp. 120–121. doi:10.17226/25353. ISBN 978-0-309-48834-1. PMID 30844154. Retrieved 2024-12-05.
3. Yogurt--an autodigesting source of lactose. J.C. Kolars et al., New England Journal of Medicine, 310:1-3 (1984)
4. Yogurt and gut function. O. Adolfsson et al., American Journal of Clinical Nutrition, Vol. 80, No. 2, 245-256 (2004)

See also

• Curd
• Cuisine of Bulgaria
• Cuisine of Turkey
• Cuisine of Greece
• Dahi
• Montenegrin cuisine
• Probiotic
• Greek products
• Ayran
• Cheese and Sirene
• Sour cream
• Kefir
• 'Yoplait' brand yoghurt
• YoGo
• Colombo Yogurt
• Cacık
• Danone
• Bulla Dairy Foods
• Müller
• Yeo Valley Organic
• Clabber (food)

External links

• IndiaCurry.com Making Dahi Yogurt at home in USA
• Persian Mast (Yogurt)
• US National Center for Home Food Preservation: Fermenting Yogurt at Home
• Encyclopaedia of Turkey: Yoghurt
• Yogurt Forever: The Yogurt Encyclopaedia (PDF)

• Fermented foods
• Dairy products
• Desserts
• Yoghurts
• Words of Turkish Origin