The research sought to investigate the functional properties of starches obtained from four Nigerian root and tubers, yam and sweet potato varieties, in order to facilitate their exploitation as substitute raw material for the local food and pharmaceutical manufacturing industry. The varieties, namely: white yam (Dioscorea rotundata), water yam (Dioscorea alorta), orange flesh sweet potato (Ipomoea batatas) and cream flesh sweet potato (Ipomoea batatas), their respective starches were obtained by wet separation techniques and were analyzed for their pasting properties, physic-chemical properties, starch yield on dry and wet basis, functional, starch purity, amylase and amylo-pectin were undertaken in order to determine their suitability for food and other uses. The peak time, pasting temperature, peak viscosity, holding strength, breakdown, set from peak and set back from through ranged from 7.3 – 8.3 mins, 65.4 – 71.3°C, 511.5 – 1001.2 BU, 860.8 – 871.3 BU, 300.1 – 306.9 BU, 240.8 – 248.1 BU and 400.4 – 510.9 BU respectively. There were significant differences (p<0.05) in the pasting properties. The crude protein, crude fat, crude fibre, ash, moisture and carbohydrate ranged from 1.55 – 1.85%, 0.09 – 0.12%, 0.12 – 0.22%, 1.32 – 2.05%, 10.72 – 11.09% and 85.59 – 86.20% respectively. There were significant differences (p<0.05) in the proximate composition of the starches. The starch yield on dry weight basis, starch weight on fresh weight basis, starch yield from tubers and percentage dry matter ranged from 56.84 – 85.88%, 22.75 – 36.07%, 18.02 – 26.00% and 40.02 – 44.01% respectively. There were significant differences (p<0.05) in the all the parameters. The bulk density, water absorption capacity, oil absorption capacity, gelatinization temperature, starch purity, amylase, amylo-pectin and pH ranged from 0.56 – 0.61g/cm3, 86.8 – 99.4%, 103.2 – 125.4%, 59.78 – 60.42°C, 95.28 – 96.55%, 27.25 – 29.37%, 70.63 – 72.63% and 6.82 – 6.91 respectively. There were significant differences (p<0.05) in all the parameters but no significant difference (p>0.05) in the pH. The starches from yam and sweet potato varieties starches can be exploited for diverse uses based on their different characteristics.

The physicochemical properties of Wheat, sweet potato and cashew nut flour blends were studied. The sweet potatoes were washed; peeled; sliced; dried, and milled to Flour. The cashew nuts were also sorted, cleaned and processed into Flour. The Wheat, sweet potato and cashew nut Flour were proportioned into different samples G1 (100:00:00). Control samples were 100 % wheat flour, G2 (80:10:10), G3 (70:20:10) and G4 (60:30:10) respectively. Bread from these different proportions was formulated. The functional, proximate, physical properties and sensory properties were determined. GENSTAT Statistical Software (version 17.0) was used for data analyses. The Data obtained showed the following ranges for Bulk density (0.83-0.84 g/ml), water absorption capacity (3.65-5.78 g/g), oil absorption capacity (1.73-2.76 g/g), swelling index (7.22-7.94) and pH (5.95-6.00). Proximate compositions of the Bread showed the following ranges for moisture (30.14-34.68 %), protein (7.89-13.03 %), fat (8.82-952 %), fibre (1.23-4.34 %), ash (0.56-2.02 %) and carbohydrates (38.86-51.37 %). The physical properties of the Bread ranged from 210.60-247.50 g, 1.27-2.40 mm, 328.70-440 cm3 and 1.33-2.10 for loaf weight, oven spring, loaf volume and specific volume, respectively. Sensory evaluation findings indicated that up to 30 % substitution of sweet potato flour and 10 % cashew nut flour for wheat flour was acceptable in bread formulation.

The research is aimed at adding value to sweet potato based biscuits using underutilized crops such as cashew nuts. The objective of the study was to add value to sweet potato based biscuits, the sweet potato was processed into flour; while the cashew nuts was unroasted cashew nuts were sorted to remove the stones, dirt’s and unwholesome cashew nuts, roasted, shelled, dried, peeled and processed into flour and sieved. The cashew nuts flour was substituted at 20, 30, 40 and 50% into sweet potato flour to produce sweet potato and cashew nuts composite flour were  used for the production of biscuits. Functional, proximate composition of the biscuits, physical and sensory properties of composite biscuits were determined. Significance difference (P<0.05) was observed Bulk density, water absorption capacity, oil absorption capacity, swelling capacity, emulsion activity, foaming stability and gelatinization temperature increased from 0.62 to 0.73 g/cm3, 1.31 to 1.81 g/g, 2.10 to 2.22 g/g, 6.42 to 7.18 ml, 59.71 to 60.51%, 6.19 to 6.43% and 68.20 to 72.10ºC, respectively with an increase in the addition of cashew nuts flour. The crude protein, crude fat, crude fibre and ash increase from 14.65 to 18.31%, 7.88 to 10.21%, 3.21 to 3.51% and 4.10 to 4.76% respectively; while the moisture and carbohydrate content of the biscuits decreased from 13.77 to 13.31% and 56.39 to 49.89%, respectively with increase in the addition of the cashew nuts flour. The physical properties of the composite biscuits such as the weight, thickness, diameter and spread ratio ranged from 16.09 to 17.45 g, 10.87 to 10.96 mm, 38.94 to 40.02 mm and 3.56 to 3.60 respectively. The average means scores for the appearance, crispness, taste, aroma and overall acceptability increase were observed. There was a significant difference (p<0.05) in the appearance, taste and aroma while there was no significant difference (p>0.05) in the crispness and overall acceptability.