Tamarind pulp is the edible fruit of the tamarind tree. They comprise of seeds and flexible green shell (when fresh). Tamarind is one of the significant ingredient used in South Indian cooking. India is the largest producer and consumer of this. They are known as Imli in Hindi and puli in Tamil. Tannins, saponins, sesquiterpenes, alkaloids and phlobatamins present in tamarind acts against gram positive and gram negative bacteria. They are used as a treatment for gastric and digestive problems.
When dried, the green shells turns brown and hard. During cooking, along with the seeds, the hard shell is discarded before use. Tamarind pulp is soaked in lukewarm water for minimum 15 minutes to soften and the juice is squeezed out of it with hands or using a food processor. The strained juice which has a tangy taste is used for cooking and it is acidic in nature.
I prefer the natural dried variety sold as brick bars in the Indian grocery shops. Tamarind pulp is also sold as extracted paste in plastic containers in the shops.Tamarind is used mainly in preparations like rasam, puli kozhambhu (simmered tamarind gravy),chaat chutneys and tamarind rice.