Research Journal of Earth and Planetary Sciences

Global Research Journal of Agricultural and Biological Sciences Vol.3(4) pp.330 –335  October 2012.

Available online http://www.globalresearchjournals.org/?a=journal&id=grjabs

Copyright ©2012 Global Research Journals

 

 Full length Research.

 

Functional and Pasting Properties of Wheat/ Three-leaved Yam (Dioscorea dumentorum) composite flour blend.

Eke-Ejiofor, J and Owuno, F

Department of Food Science and Technology,Rivers State University of Science and Technology,

Port Harcourt, Nigeria.

Corresponding Author’s E-mail: joyekee@yahoo.co.uk,Tel: +2348033414797 

Abstract.

The study investigated the functional, pasting and chemical properties of wheat/three-leaved yam (TLY)(Dioscorea dumentorum) composite flour blends. Wheat flour was collected from Port-Harcourt Flour Mill, while flour from three-leaved yam was produced using standard procedures. The flour samples were blended into different proportions of 100%wheat and 100% three-leaved yam(TLY) flour, wheat/TLY blends of 90:10, 80:20, 70:30,60:40 and 50:50. The pasting properties of flour blends were significantly different (p<0.05) from that of the 100% wheat flour. Peak viscosity, trough and break down values of blends decreased with increase in substitution, ranging from 84.67 -95.88 RVU, 48.17-59.86 RVU and 20.0-45.70 RVU respectively.  Final and set back viscosities of flour blends increased with increase in substitution, ranging from 132.67 -173.92 RVU and 82.5 – 122.42 RVU respectively. Time and temperature to attain peak viscosity ranged from 5.8 -6.2min and 49.3 -49.7°C. Functional properties increased with substitution and ranged from 8.20 -10.90%, 71.30 -94.84% for swelling power and water absorption capacity respectively. While dispersibility decreased with substitution and ranged from 50-72%. Solubility and color indices showed no significant (p>0.05) difference between the 100% wheat and three –leaved yam flour. Results of chemical analysis showed that substitution had a significant effect (p<0.05) for all the parameters analysed except sugar content. Moisture, amylopectin ash and fat contents increased with increase in substitution and ranged from 7.36-11.42%, 66.27-76.79%, 0.65-3.01% and 1.42-4.8% respectively. The present study showed that compositing the popular wheat flour with locally available under-utilized root crop like three-leaved yam flour is desirable in terms of functional, pasting and chemical  characteristics.

Keyword: composite flour,  wheat, three-leaved yam., functional, pasting, properties.