EFFECT OF GRAIN FERMENTATION AND MALTING TIME ON THE QUALITY OF FLOUR AND BISCUIT FROM AKSUM FINGER MILLET (Eleusine coracana)

Abstract

Finger millet grain is nutritious and comfortable in protein, fat and minerals. However, anti-nutrients are a major barrier hindering the utilization, of finger millet grains. Fermentation and malting are believed to reduce anti-nutritional factors and enhance the bioavailability of nutrient composition. Biscuits are usually produced from wheat flour, increasing wheat demand with limited supply. The study investigated the effects of grain malting and fermentation time on the quality of Aksum finger millet flour and resultant biscuits. The experiment was planned with two factors; fermentation and malting times. Three treatments of each factor were executed using completely randomized design. Fermentation times were 24, 36, and 48 hours while the malting time were 24, 48, and 72 hours. Selected engineering properties of the seed were recorded to be 11.44% (db) moisture content, 32.58° angle of repose, 0.72 g/mL bulk density, 1.15 g/ml true density, 36.94% porosity, 0.78 sphericity, 11.02 mm2 surface area, 1.11 mm3 volume, and 3.76 g thousand-grain weight. The physical properties of flour were determined as the angle of repose (35.32-45.72°), colour values such as L* (72.14-74.66), a* (2.82-3.73), and b* (6.78-8.01). The highest recorded values of particle size distribution were between 355 and 250 μm. The functional properties such as, water absorption, oil absorption, swelling power, and solubility index of Aksum finger millet flour were in the range of 1.21-1.91 g/g, 1.83-2.35 g/g, 2.28-2.46 g/g, and 2.38-2.53%, respectively. The proximate composition of the flour was 8.64-10.10% moisture, 6.10-7.18% crude protein, 1.29-1.53% crude fat, 2.43-3.67% crude fiber, 1.70-2.16% total ash, 75.00-77.35% utilizable carbohydrate and 345.00-351.22 Kcal/100g of energy content showing significant (P<0.05) differences due to fermentation and malting duration. The results of mineral contents were 4.02-5.77, 3.69-5.21, and 360.00-392.58 mg/100g for zinc, iron, and calcium respectively. The anti-nutritional contents such as phytic acid (432.32-436.66 mg/100g) and condensed tannin (1.07-1.38 mg/100g) were significantly (P<0.05) affected by fermentation and malting times. The proximate composition, minerals, and anti-nutrient contents were affected considerably by fermentation (48) and malting (72 hours). The Physical parameters and sensory scores of biscuits were significantly improved with increasing processing times. Conclusively, fermentation and malting improved the acceptance of flour and biscuits.