EFFECTS OF GERMINATION AND FERMENTATION TIMES ON SOME ENGINEERING PROPERTIES OF THE FLOUR OF SORGHUM [Sorghum Bicolor (L) Moench] AND SENSORY QUALITY OF THE PRODUCT

Abstract

The study was conducted on the effect of germination and fermentation time on some engineering properties of the flour and sensory acceptability of kita product of sorghum [Sorghum bicolor (L) Moench].The experiment was planned with two factors; germination and fermentation times. It consisted of nine combinations of treatments executed in a completely randomized design (CRD). The germination times were 72, 96 and 120 hrs and the fermentation times 24, 48 and 72 hrs. The physical properties such as bulk density and angle of repose of the processed flours ranged from 0.56-0.66 g/mL and 35.53-37.73o, respectively and were statistically lower values than the 0.72g/mL and 39.45o values of the control sample flour. The proximate compositions of the flour samples ranged from 1.57-1.78% for ash, 3.15-3.91% for fiber, 2.84-3.33% for fat, 7.27-8.44% for moisture, 13.67-14.62% for protein, 69.23-70.10% for carbohydrate and 361.05-365.47 kcal/100 g for energy value. These values except protein and energy were significantly (P<0.05) lower than the corresponding values of 1.87%, 4.15%, 3.48% and 9.23%, 9.28%, 71.99%, 356.34 of the control sample flour. The antinutritional factors of the control sample were 56.98 mg/100 g condensed tannin and 354 mg/100 g phytic acid, which were significantly higher than the values of processed flours which ranged from 31.76-43.95 mg/100 condensed tannin and 275.41-346.30 mg/100g phytic acid. The functional properties such as water and oil absorption, swelling power, solubility and dispersibility of unprocessed sorghum flour were 1.69 g/g, 1.77 g/g, 1.55 g/g, 7.83% and 70.33% while those of the processed flour ranged from 1.62-1.80, 1.89-2.96, 1.35-1.50, 12.77-19.00 and 72.83-74.67, respectively with the relevant units indicated. All values except swelling power of those treated samples were increased significantly after both effects. The pasting properties of control sorghum flour included 2418.00, 1183.67, 1234.33, 3125.67 and 1841.00 cP of peak, trough, breakdown, final and set back viscosities, respectively and 4.84 min of peak time as well as 85.00 oC of pasting temperature. Values of the same attributes for the treated flour ranged 70.67-158.33, 25.33-37.34, 43.67-122.33, 31.67-62.34, 3-15.00, 3.35-3.59 and 75.00-77.50, respectively with the relevant units indicated. Regarding the rheological properties, raw sorghum flour exhibited 66.61% water absorption, 15.07 min development time, 14.60 min stability time, 85.00 FU of degree of softening and 153.33 FU of farinogram quality number as compared to the values 52.20-64.70, 0.77-1.6 min, 0.85-4.30 min, 109.00-140.00 FU and 7.33-20.33 FU of the respective properties of processed flour. Sensory acceptability data of kita showed increased scores in all attributes after germination and fermentation processes. The control sample is the lowest score for each of the sensory attributes and treated samples showed positive acceptability