Volume : 2, Issue : 12, December - 2013

Microbial, Physico–Chemical and Nutrient Changes Associated with Idli Batter Fermentation

Mrs. S. Sheela, Dr. S. Kowsalya

Abstract :

Fermentation is one of the oldest methods of food preparation that originated centuries ago. Although idli is a common South Indian food, the method of preparation varies from one place to another. The study was carried by inging out variations in the addition of ingredients namely rice and black gram dhal in various proportions like 3:1, 4:1 and 4.5:1 respectively and allowing the batter to ferment for 16 to 18 hours at different temperatures like 22 oC, 27 oC and 32 oC. Physico–chemical characters like pH, titrable acidity and batter volume, along with mean scores for the overall acceptability of the sensory parameters showed that the variations of rice: black gram 3:1 and 4:1 at room temperature (27 oC) were found to be highly acceptable. The total microbial count was found to improve gradually with an increase in the hours of fermentation (3x103 cfu/g at zero hours to TNTC at 36 hours). Leuconostoc sp. and Saccharomyces sp. isolated at zero hours and present up to 24 hours of fermentation were found to be the microorganisms responsible for fermentation of idli batter. A comparison of the nutrient content of idlis made from fermented and unfermented batters showed an increase in the proximate principles, minerals, B vitamins and a decrease in phytate content.