ABSTRACT

 The physicochemical properties of blends of germinated whole wheat flour and starch from different varieties of yam were studied. Different varieties (D. alata, D. bulbfera, D. dumetorum and D. rotundata) were processed to obtain starches, wheat grains were also germinated and processed into flour. The different starches were blended with the germinated wheat flour to obtain 5 different flour blends including a 100% wheat flour as control. The different flour blends including the control sample were subjected to functional, proximate, colour profile, amylose and amylopectin composition and pasting properties analyses using standard methods. The functional properties ofthe flour samples ranged from 0.66 to 0.75 g/ml bulk density, 0.75 to 1.50 g/g water absorption capacity (WAC), 0.93 to 1.08 g/g oil absorption capacity (OAC), 1.11 to 1.38 swelling index, and 74.50 to 84.00°C gelatinization temperature (GT). The proximate composition of the flour samples ranged from 7.18 to 7.82% moisture content, 13.88 to 15.56% protein, 2.96 to 3.28% crude fibre, 1.94 to 2.14% fat, 2.08 to 2.67% ash, 69.43 to 71.39% carbohydrate, and 357.75 to 359.50 kcal/100 g energy value. The colour profile ofthe flour samples showed ranges of 61.15 to 79.37 for L* (lightness), -5.43 to -1.42 for a* (redness-greenness), and 4.47 to 10.24 for b* (yellowness-blueness). The amylose and amylopectin composition of the flour samples ranged from 25.28 to 31.40% amylose and 68.60 to 74.72% amylopectin. The pasting properties ofthe flour samples ranged from 31 to 50 RVU for peak viscosity, -5 to 7 RVU for trough viscosity, 24 to 55 RVU for breakdown viscosity, 0 to 28 RVU for final viscosity, 5 to 23 RVU for setback viscosity, 3.07 to 3.27 minutes for peak time, and 0 to 71.8°C for pasting temperature. The study demonstrates that blending germinated whole wheat flour with starches from different yam varieties significantly modifies the functional, nutritional, colour, and pasting properties of the composite flours.