Effect of stabilizers on stabilization of idli (traditional south Indian food) batter during storage

Idli, a steam cooked traditional fermented Indian food prepared from a wet ground mixture of rice and black gram dhal, is famous for its soft, spongy texture, desirable sour taste and characteristic aroma. A commonly observed phenomenon with idli batter is whey separation that occurs due to collapse in its volume after a certain period of fermentation, and which increases with storage. Idlis made from such batter give a very hard texture. The present work aims at stabilization of the idli batter at room temperature (28-30 °C) and refrigerated storage (4-8 °C) by using various hydrocolloids and some surface-active agents. The batter was evaluated in terms of % decrease in volume, and % whey separation. While hydrocolloids gave good stabilization, surface-active agents failed to stabilize the batter although they reduced whey separation. Among the various hydrocolloids, 0.1% guar gave best batter stabilization, and idlis made therefrom after 10 days of room temperature and 30 days of refrigerated storage of batter were found to be of acceptable quality.