Physicochemical, functional and pasting properties of flour produced from gamma irradiated tiger nut (Cyperus esculentus L.)

Tiger nut (Cyperus esculentus L.) has been recognised as one of the best nutritional crops that can be used to augment the Ghanaian diet. The application of gamma irradiation as means of preserving tiger nut could modify the characteristics of resultant flour. The purpose of this study was to determine the physicochemical, functional and pasting characteristics of flour from gamma irradiated tiger nut. The yellow and black types of tiger nut were sorted, washed and dried in an air-oven at 60oC for 24h. The dried tiger nut samples were irradiated at 0.0, 2.5, 5.0 and 10.0kGy and then flours produced from them. Moisture, ash, pH, titratable acidity, water and oil absorption capacities, swelling power, solubility, bulk density and pasting properties of the flours were determined using appropriate analytical methods. Results showed that irradiation did not significantly (P>0.05) affect the moisture and ash contents of the resultant flours. Gamma irradiation significantly (P≤0.05) increased titratable acidity with concomitant decrease in pH of the flours. No significant differences were observed for water and oil absorption capacities, swelling power as well as bulk density. Solubility significantly (P≤0.05) increased generally with irradiation dose. Peak viscosity, viscosities at 92°C and 55°C, breakdown and setback viscosities decreased significantly with irradiation dose. Flour produced from irradiated tiger nut has a potential in complementary food formulations due to its low viscosity and increased solubility values. •Physicochemical, functional and pasting characteristics of flour from gamma irradiated tiger nut were studied.•Irradiation did not affect the moisture and ash contents of the resultant flours.•Titratable acidity increased with decrease in pH of the flours from the irradiated tiger nut.•Solubility increased whereas peak viscosity decreased with irradiation dose.•Flour produced from irradiated tiger nut has a potential in complementary food formulations.