STUDIES ON SOME PHYSICAL AND RHEOLOGICAL PROPERTIES OF SWEET LUPIN (Lupinus angustifolius) FLOUR AND ITS BLENDING EFFECT ON QUALITY OF WHEAT-BASED COOKIE AT DIFFERENT BAKING TEMPERATURES

Abstract

A study was conducted on some engineering properties of lupin seed and flour and its blending effect on quality of cookie. The experiment was planned with two factors: blending ratio and baking temperatures. Twelve combinations of treatments executed using factorial experiment. Lupin blending ratios were 0, 10, 20, and 30% while the baking temperatures were 160, 170, and 180oC. The physical properties of lupin seed and flour were recorded to be 9.65 and 8.25% wb moisture content, 0.81and 0.72 g/ml bulk density and 23.92 and 41.53° angle of repose. The other physical properties of grain were length 6.21, width 5.01, thickness 4.23 geometric and arithmetic mean diameter 5.08 and 5.15 all in mm, sphercity 0.82, surface area 81.52mm2, unit volume 22.18mm3 aspect ratio 0.81 and hydration parameters were recorded. The color of lupin flour were recorded with L = 78.12, a* = 4.33 and b* = 17.17. The functional properties such as water and oil absorption capacity, swelling power, solubility and dispersibility of lupin flour were 3.09 g/g, 1.37 g/g, 4.97 g/g, 14.17% and 54.17% , while those of wheat flour were 1.33 g/g, 1.65 g/g, 4.76 g/g, 6.30% and 73.87%, respectively, and significance (P<0.05) differences from each other was observed. The pasting properties of lupin flour were peak viscosity (78.04), trough viscosity (15.32), final viscosity (25.36), breakdown viscosity (62.72) and setback viscosity (10.04) all in cP,while those of wheat flour 2487.02, 1097.81, 2585.45, 1389.21 and 1487.65 cP were recorded, respectively. The Rheological properties recorded were water absorption of 80.52%, development time of 4.46 min, stability time of 1.26min and farinogram quality number of 25.89 FU while values of 55.86%, 2.11 min, 5.02 min, and 80.52 FU of the respective properties were recorded for wheat flour, respectively. The proximate composition of cookies including 4.15 - 4.66% moisture, 6.78 - 9.04% cude protein, 18.08 - 9.62% crude fat, 0.35 - 0.48% crude fiber, 1.16 - 1.48% ash, 65.59 - 68.96% carbohydrate and 465.71 to 473.68 Kcal/100g of energy content were recorded showed significant (P<0.05) difference due to blending ratios. The mineral content such as calcium, iron and zinc and physical properties such as diameter, thickness and spread ratio of cookie were also significantly (P<0.05) affected by blending ratios. Sensory acceptability data of cookies showed that increasing the blending ratio resulted in increased scores of all attributes while an increase in baking temperatures decrease the values with significance (P<0.05) difference due to blending ratios and baking temperatures, except aroma and flavor.