Yoghurt

Yoghurt (also spelled yogurt) is a food made from milk by the addition of specific bacteria that convert the milk's lactose (milk sugar) into lactic acid. This acid lowers the pH of the milk, which denatures the milk proteins (casein), causing the milk to thicken and curdle.

Yoghurt is an ancient food well known in the Middle East, Central Asia, the Balkans, India, and East Africa. The word itself is said to derive from Ottoman Turkish (yoğurt). Today it is a global food, sold in various forms: plain, strained (Greek-style), flavored, and drinkable.

Making yoghurt

Milk is first heated to kill unwanted bacteria and alter some of the proteins. It is then cooled to around 40–45 degrees Celsius, and a starter culture containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus is added. These two types grow cooperatively. The culture is held at this temperature for several hours until the acid reaches the desired level, then cooled to stop fermentation.

Nutrition

Yoghurt contains protein, calcium, phosphorus, and B vitamins. Because the bacteria consume some of the lactose, people who have difficulty digesting milk lactose often find yoghurt easier to tolerate. Strained varieties, such as Greek yoghurt, contain more protein per serving because some of the liquid and whey have been removed.

Food uses

Yoghurt is eaten on its own or added to bread, salads, and sauces. In the Middle East and Asia, it is used to make drinks such as lassi and ayran, and as a marinade for meat, since the acid tenderizes it. A thick, strained variety (labneh) is also made and used like cheese.