Properties of idli batter during its fermentation time

Idli is a traditional fermented rice and black gram-based breakfast food of South India. Idli batter was prepared from soaking polished parboiled rice and decorticated black gram for 4 h at 30 +/- 1C in water. The soaked mass was ground to 0.5- to 0.7-mm particle size batter using wet grinder with adequate amount of water. The blend ratios of 2:1, 3:1 and 4:1 (v/v) batter were allowed for fermentation (0, 6, 12, 18 and 24 h) adding 2% of salt. The idli batter parameters viz. bulk density, pH, percent total acidity, flow behavior index and consistency coefficient were studied for different fermentation times and blend ratios. The bulk density, pH and percentage total acidity of batter during different fermentation times and blend ratios ranged between 0.94 and 0.59 g/cm(3), 5.9 and 4.1 and 0.443 and 0.910%, respectively. The consistency coefficient at any fermentation time shows increasing trend as the rice to black gram ratio increased. The flow behavior index indicated strong non-Newtonian fluid behavior (pseudoplastic) of idli batter at different fermentation times and blend ratios.