ABSTRACT

The formulation of the blends of soybeans (Glycine max) and water yam (Dioscorea alata) flours for biscuits preparation was studied. Soybean seeds and water yam tuber were processed into flours and 100% wheat flour served as the control sample. However, biscuits were produced using soybeans flour and water yam flour which were blended at different ratio (i.e. 100%:0, 90:10, 80:20, 70:30, 60:40 and 50:50). The proximate analysis and functional properties of the soybean-water yam flour were determined. The sensory evaluation showed that samples acceptability was low due to the beany flavour of most of the biscuit samples because they contained high quantity of soy bean flour. The physical analysis showed that there was no significant difference (P>0.05) in weight and thickness of the samples. The proximate composition of biscuit samples shows the moisture, protein, fat, ash, crude fibre and carbohydrate ranged from 5.83% —6.72%,9.63% — 10.52%, 22.15% -24.15%, 1.44% - 1.77%, 0.30% - 0.38% and 57.86% — 59.89% respectively. There were significant difference (P < 0.05) between the samples. The functional properties of the flour samples shows that the bulk density, water absorption, oil absorption, swelling capacity and wettability ranged from 0.35g/ml - 0.43g/ml, 2.l0g/ml - 3.70 g/ml, 0.35g/ml - 0.43g/ml, 0.12% - 0.27%, 1 l2secs - 178secs respectively. There were significant differences (P <0.05) in all their values expect in wettability, bulk density and oil absorption capacity. The physical properties of biscuits sample showed that diameter, thickness, weight spread ratio from 5.07 to 5.60%, 0.20%-0.20%, 4.12-8.73%, 19.20-27.50% were significantly different (P >< 0.05) between composite biscuit and 100% biscuit expect in thickness. The sensory evaluation of biscuit shows that appearance, flavour, texture, crispiness and general acceptability ranged from 5.65% -8.00%, 4.20% - 7.85%, 3.70-8.30%, 2.90% -7.95% and 4.65 -8.20% respectively. There was significant (P<0.05) difference between the samples expect in appearance. The total viable count of genera bacteria ,coliform count, staphylococuss count, lactobacillus count were determined for four weeks according to microbiological standard method and their concentration where measured. The total viable count of genera bacteria ranged 3 x iO3— 1.35x105, 2x103— 4x103for fungi (mold), 2x103— 1.17x105for staphylococcus, 5x 1 0 — 4x 1 for Lactobacillus and no results on coliform count.