Study on Malting Condition of Millet and Sorghum Grains and The Use Of The Malt in Bread Making

Abstract

This study was carried out to test the effect of addition of grain malts to wheat flour on the quality of bread. The results of chemical composition of millet and sorghum (Tabat and Faterita) grains before and after germination showed significant increase in protein content when the grains germinated, significant decrease in fiber content and insignificant increase in reducing sugars. Different soaking conditions prior to malting, were examined including distilled water, tap water, 0.5% and 1% sodium chloride solutions, and soaking water with variable pH values of 5, 6, 7 and 8. Germination conditions of different incubation temperatures (25, 30 and 35oC) and time (24, 48 and 72 hours) were also examined in order to optimize amylase activity. The falling number test was used to determine the activity of α-amylase. Optimization of malting temperature and time were first examined. Results indicated that the incubation temperature 25oC for millet and sorghum (Tabat and Faterita) grains was reduced significantly the falling number of germinated grains, as the time progressed from 24 to 48 and 72 hours. Incubation temperature of 35oC for millet and sorghum (Tabat and Faterita) significantly increase the falling number with time. Incubation temperature of 30oC for millet resulted in a significant decrease in falling number from the 24 germination time, thereafter it remained unchanged up to 72 hours. Both Tabat and Faterita responded to incubation temperature of 30oC, the falling number significantly reduced from initial to the first 24 hours. Then it significantly increased with progress of time (24, 48, and 72 hours). Pre-malting treatment indicated that soaking cereal grains (millet, Tabat and Faterita) in distilled water gave significant lowering of falling number for their malts (i.e higher α-amylase activity) if compared with soaking in NaCl solution of 0.5% and 1%. Despite of their insignificant variation in falling numbers, soaking grains in distilled water gave the lowest malt falling number comparable to tap water. Both pH 7 and 8 gave an insignificant difference in falling number tests but soaking the grains in pH 7 revealed the lowest malt falling number in millet and Faterita germinated grains. The specific volume of bread increased when millet and Faterita malt were added to wheat flour to 4.506 and 4.306 respectively, while Tabat malt showed decrease in the specific volume (4.12) comparable to control sample (4.187). The sensory evaluation of bread samples showed that the bread baked from composite wheat flour and millet malt showed best result according to the preference of panelists in appearance, taste, colour, texture and odour.