ABSTRACTS

Foam-mat drying of Ngu using egg white as foaming agent was investigated. The egg white was incorporated into Ngu sample (60, 80 and 100 % concentration) at 20, 25 and 30 % and whipped for 5, 9 and 12 mins in room temperature. A central composite response surface design was used to study the effects of the variables- whipping time, egg white and Ngu concentration on selected physiochernical and sensory properties of dry Ngu powder. Regression models showed that the experimental variables had significant (p<0.05) effects on the iron, zinc, calcium, sodium, phosphorus, potassium, magnesium, drying yield, foam stability, foam density, drainage mean time, moisture content and pH of the dry Ngu powders. For all responses, the optimum obtainable values were achievable at optimum factor combination of 10 mins whipping time, 20.8 % egg white and 100 % Ngu concentration. Optimum values obtainable for the mineral composition of Ngu powder were 17.46 mg lg,1.03 mg/g, 0.58 mg/g, 12.72 mg/g, 2.26 mg/g, 1.36 mg/g and 0.26 mg/g for the iron, zinc, calcium, sodium, phosphorus, potassium and magnesium, respectively. Optimum values obtainable for the physicochemical properties of the Ngu were 20 %, 23.98 g/cm3, 294.38 mins, 3.85 %, 143.53 % and 7.98 for drying yield, foam density, drainage mean time, moisture content, foam capacity and pH respectively. With reference to the foam stability optimization, the optimum values for the foam stability at 30, 60, 120 and 180 mins were 100.82 %, 99.26 %, 98.34 % and 91.52 % respectively, all obtainable at the optimum factors combination of 10mins whipping time, 20.8 % egg white and 100% Ngu concentration. Panelists made up of twenty (20) persons were used to score the dry Ngu powder for taste, appearance, handfeel, smell and Abacha (African salad) for taste, mouthfeel, appearance on a 9-point hedonic scale. The dry Ngu powder produced from 12 mins whipping time, 30 % egg white,100 % Ngu concentration was the most preferred of all the samples in terms of all the sensory attributes evaluated. Abacha/Ighu prepared with reconstituted dry Ngu powder produced from 5 mins whipping time, 20 % egg white and 100 % Ngu concentration) compared well with the control (100 % Ngu concentration) which is already in use.