Tamarind Seed

The tamarind tree is a large, long-lived evergreen with feathery leaves and brown, bean-like pods that hold sticky, tangy pulp. Each pod contains several flat, shiny seeds, dark reddish-brown and extremely hard, about a centimetre or more across. Each seed has a tough outer coat surrounding a pale kernel. The seeds are normally separated from the pulp when tamarind paste or concentrate is made and are often discarded, but they can be roasted, boiled or ground. A roasted seed tastes somewhat like a hard, dry bean, with a slight bitterness from tannins in the coat.

The tamarind tree is generally believed to be native to tropical Africa, with Sudan and the dry savannas of the Sahel often cited, and it was carried to the Indian subcontinent very early. Its Latin species name, indica, and the English word tamarind, from the Arabic tamr hindi meaning date of India, reflect that long association with India. It was later taken to Southeast Asia, the Caribbean, Mexico and tropical Latin America, where it thrives in hot, seasonally dry climates. India is a leading producer, with Thailand, Mexico and several African countries also growing it widely.

People have valued tamarind pulp for thousands of years, but the seeds had a quieter story. In rural India and parts of Africa the seeds were roasted and eaten as a snack in times of scarcity, or boiled to remove the bitter coat. In textile regions the ground kernel was boiled into a paste called tamarind kernel powder and used as a sizing agent for strengthening cotton and jute threads before weaving.

In the twentieth century researchers identified the main carbohydrate in the kernel as a xyloglucan, a branched polysaccharide that forms thick gels. It is sold as tamarind seed gum or tamarind kernel powder and is used in food, pharmaceuticals and cosmetics, most prominently in Japan, where it is permitted as a thickener and stabiliser in sauces, ice cream and bakery products. Meanwhile roasted seeds remain a village food in several countries.

Roasted seeds are cracked and eaten as snacks, or soaked and boiled until soft after the coat is removed. The kernel can be ground into flour for porridge or blended with cereal flours, as was done in some regions during famine. Tamarind seed polysaccharide is used as a thickener in sauces, sweets, jellies, ice cream and glazes, and as a stabiliser in beverages. Outside food it is used in textile sizing, paper making, cosmetics and eye-drop formulations.

Tamarind kernel flour is largely carbohydrate, with modest amounts of protein and fat, and it contains polyphenols such as tannins. Published values vary with the variety and the processing method, so the figures here are approximate. Tamarind seed polysaccharide is a soluble fibre-like material that is being studied in food science for its thickening and stabilising properties. As a food, the seeds are a minor and regional source of calories, not a major dietary staple. Processing is important because raw seed coats are bitter and hard.