Changes in acidity and lactic acid production during ititu fermentation

Abstract

The fermentation rate and acidity of ititu, and Ethiopian fermented cow's milk, was investigated. Changes in pH and total titratable acidity, volatile organic acids and bacterial counts of fermenting milk samples kept at room temperature (21 deg C) and 28 deg C were recorded. Similar parameters were also monitored for pasteurized milk incubated at room temperature. In raw milk incubated at room temperature, the pH decreased from 6.6 to 4.2 while the lactic acid content increased from 0.2 percent to 1.4 percent within 24 h of fermentation. In pasteurized milk, the drop in pH and acid production patterns were very low during the first 24 h of fermentation. Raw milk incubated at either room temperature or 28 deg C was found better than pasteurized for production of ititu. The higher incubation temperature increased the tempo of fermentation and shortened the time required for development of flavor, aroma and texture in ititu. However, the desirable characteristics in ititu were fully developed when incubated at ambient temperature (21 deg C).