ABSTRACT

The study to evaluate the suitability of cocoyam (Colocasia esculenta) flour composites in cookies production was conducted.  The functional and pasting characteristics of the different composites (0 - 40%) of cocoyam flour with wheat flour were determined. The proximate, mineral, antinutritional, physical and sensory properties of cookies produced from the composite flours were evaluated. The pasting properties were analysed using rapid visco-analyzer while sensory characteristics of cookies were evaluated by panelists (n=20) for taste, aroma, colour, texture and general acceptability. Results of the functional properties of the wheat-cocoyam composite flours differed significantly (p<0.05), with 100% wheat flour having the highest values in emulsion and foam capacities and in foam stability. The values ranged from 0.63 to 0.69 g/ml for bulk density, 0.95 to 1.75 g/g sample for water absorption capacity, 1.45 to 2.45 g/g sample for oil absorption capacity, 14.68 to 35.57% for foam capacity, 10.28 to 19.98% for foam stability, 34.44 to 43.58% for emulsion capacity, 1.14 to 1.34% for swelling index, 14 to 20% for gelation capacity, 68 to 78 °C for gelatinization temperature and 157.00 to 449.50cP for viscosity. The pasting properties including peak viscosity, peak time, trough breakdown, final viscosity and setback varied significantly (p<0.05) among samples, with no definite trend. Range of values obtained include 208.67 – 281.00 RVU (peak viscosity), 30.83 – 94.25 RVU (breakdown viscosity), 140.42 - 225.58 RVU (trough viscosity), 226.08 – 371.00 RVU (final viscosity), 80.08 – 220.33 RVU (setback viscosity), 70.33 – 83.66 °C (pasting temperature) and 4.93 – 5.61 min (peak time).  Results of the proximate composition of the cookies were in the range of 3.10 – 5.30% (moisture), 7.00 – 11.33% (protein), 12.20 – 14.33% (fat), 2.00 – 2.70% (crude fibre), 2.10 – 2.75% (ash) and 61.33 – 71.10% (carbohydrate). Cookies from 100% wheat flour had higher contents of protein, fat and ash but lower contents of crude fibre, carbohydrate and moisture than the composite cookies. Cookies from 100% wheat flour had higher mineral contents than the composite cookies. Results of the physical properties showed that the composite cookies had higher values for diameter, spread ratio and cookies’ weight. The sensory characteristics showed no definite trend in the sensory qualities of the cookies and also showed no significant (p>0.05) difference among samples produced from the different composite flours and the control, indicating that the different cookies were favourably similar and comparable. Except for phytate, cookies from the flour composites had higher values than the 100% wheat flour cookies in the antinutritional properties studied. However, they were all below the safe limit thresholds of all the antinutrients. Therefore, wheat:cocoyam flour composites can be adopted for the production of good quality cookies.