Physicochemical and pasting characterisation of water yam (Dioscorea spp.) and relationship with eating quality of pounded yam

Author: F. D. Baah ^1*, B. Maziya-Dixon ², R. Asiedu ², I. Oduro ¹ and W. O. Ellis ¹

Received 4 January 2009, accepted 16 March 2009.

Abstract

Food quality improvement of D. alata for diverse uses is imperative due to its good agronomic flexibilities. The relationship between physico- chemical and pasting characteristics of 15 D. alata varieties and eating quality of pounded yam (the most popular food from yam) was studied in comparison to a control variety. The test varieties had lower starch content (68.3%), swelling power (9.9), peak viscosity (283.9 RVU), trough (221.5 RVU), breakdown (20.2 RVU), final viscosity (283.9 RVU) and setback (62.4 RVU) but higher sugar (5.4%), solubility (11.9%), peak time (6.3 minutes) and pasting temperature (89.2^oC) than the control variety. Multiple comparison sensory tests by a trained panel showed poor quality of pounded yam from test varieties relative to the control, however, TDa 98-159 and TDa 291 compared well with the control. Significant relationships existed between the quality of pounded yam and physicochemical/pasting characteristics. Little improvement of promising varieties will enhance D. alata market value for the preparation of pounded yam.

Key words: Physicochemical properties, pasting, water yam, eating qualities, pounded yam.