Production and evaluation of baked and extruded snacks from blends of millet, pigeon pea and cassava cortex flour

Thesis Overview

<p> Millet flour (MF) and pigeon pea flour (PPF) were produced and blended in the ratio of 65:35 to obtain millet-pigeon pea flour blend (MPF). Wheat flour (WF) and MPF were used in ratios of 100: 0, 90:10, 80:20, 70: 30 and 60: 40 to produce cookies which were subjected to sensory evaluation, to isolate the best ratio (80:20). Cassava cortex flour (CCF) was produced and substituted wheat flour at different levels in the 80:20 (WF: MPF) blend to give various ratios of WF: MPF: CCF as 100:0:0, 80:20: 0, 75:20: 5, 70:20:10, 65:20:15, 60:20:20. These composite flour blends were used with baking ingredients to produce cookies and extruded snacks. Millet, pigeon pea and cassava cortex flour were analyzed for their proximate, minerals, vitamins and antinutrient contents. The MF, PPF, CCF, MPF and WF were also analyzed for their functional properties. The effects of cassava cortex incorporation, baking and extrusion cooking on the nutritional, antinutritional, microbial and sensory properties of the baked and extruded products were determined. The cookies were fed to albino rats to determine their effect on the biochemical parameters of the animals. Results obtained indicated that the chemical composition of the processed flour ranged from 7.35 to 9.50% moisture, 3.94 to 16.64% protein, 1.00 to 3.00% fat, 1.25 to 3.55% ash, 0.80 to 12.07% crude fibre, 67.86 to 77.39% carbohydrate, 83.6 to 326.8mg/100g phosphorous, 1.04 to 3.40mg/100g iron, 60.0 to 620.0mg/100g calcium, 34.06 to 232.76mg/100g potassium, 83.33 to 1666.67 (IU) Vitamin A, 1.0 to 2.0mg100g Vitamin B1, 0.00 to 0.08 vitamin B2 and 0.8 to 14.2mg/100g vitamin E. Residual anitnutrients in the flour ranged from 0.11 to 0.44% tannin, 1.0 to 1.3% phytate, 0.04 to 0.45Hu/gm hemagglutinin and 0.45 to 1.90% hydrogen cycanide. The functional properties of the flour showed some significant differences (p&lt;0.05) when compared with wheat flour. Cassava cortex flour incorporation significantly (p&lt;0.05) improved the ash, crude fibre and vitamin B2contents of the cookies and extruded snacks. The protein values were reduced from 7.44% to 6.25% as CCF incorporation increased in the baked products; while the protein values improved to 12.26% at 5% level of CCF incorporation in the extruded products. Baking and extrusion further reduced the antinutrients in the formulated products to the following ranges 0.09 to 0.33% tannin, 0.63 to 1.13% phyate, 0.00 to 0.45 Hu/mg hemagglutinin and 0.20 to 0.73% hydrogen cyanide. The bacteria and mould count ranged from 0.2 x 10 to 0.8 x 102cfu/g, while there was no coliform growth in any of the samples. All the developed products (cookies and extruded snacks) were acceptable to the panelists; however, the products produced from 70:20:10 ratio of wheat flour, millet-pigeon pea composite flour and cassava cortex flour blend were the most acceptable. <br></p>