Yogurt that has been strained to remove most of its whey, resulting in a thicker consistency than unstrained yogurt, while preserving yogurt's distinctive sour taste. Like many types of yogurt, strained yogurt is often made from milk that has been enriched by boiling off some of its water content, or by adding extra butterfat and powdered milk.
In the Indian subcontinent, regular unstrained yogurt (curd), made from cow or water buffalo milk, is often sold in disposable clay bowls called kulhar. Kept for a couple of hours in its clay pot, some of the water evaporates through the unglazed clay's pores. It also cools the curd due to evaporation. But true strained yogurt, is made by draining the yogurt in a cloth.
Strained yogurt is a good source of protein, calcium, iodine, and vitamin B12. Strained yogurt includes additional steps compared to conventional yogurt, where fermented milk is strained after coagulation to remove liquid whey and lactose, yielding higher protein content. Strained yogurt is required to have at least 5.6% protein content, relative to the 2.7% for unstrained yogurt. In western Europe and the US, strained yogurt has increased in popularity compared to unstrained yogurt. Since the straining process removes some of the lactose, strained yogurt is lower in sugar than unstrained yogurt.
It is also a rich source of dietary minerals, with calcium, magnesium, potassium, phosphorus, and zinc higher in content than in milk. Concentrated yogurts contain higher final total solid content than regular yogurts, possibly prolonging shelf life compared to regular yogurts.
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