Effect of blending ginger starch (Zingiber officinale) on the dynamic rheological, pasting and textural properties of rice flour

Rice flour (RF) was blended with ginger starch (GS) (Zingiber officinale) at various concentration levels (0, 20, 40, 60, 80 and 100%) and compared with that of cassava starch (CaS). The dynamic rheological, pasting and textural property effects of these starches on RF were studied. CaS and GS and their blends with RF all exhibited a weak gel behavior as shown by their dynamic moduli (G’ and G”) values. The higher tan δ (0.45 and 0.51) values recorded by GS and CaS respectively raised the tan δ values in their blends with RF thereby reducing the elasticity of RF. The rapid visco analyzer (RVA) results revealed that, GS exhibited the appropriate characteristics for noodle processing in most of the pasting properties as compared to CaS such as; higher trough viscosity (165.05 RVU), final viscosity (241.20 RVU) and lower swelling power (13.17 g/g). CaS gets to be selected over GS for energy conservation during cooking since it recorded a lower pasting temperature of 70.90°C likewise its formulated blends with RF. Measurement of textural property demonstrated that, the hardness and chewiness of RF could be increased (101.25-293.34 g and 47.34-72.19) respectively by blending with GS. Also, the cohesiveness of RF got to be reduced (0.51-0.27) by the addition of GS. The various properties of GS and its effect on RF blends unveiled in this study makes GS fit to be considered in the modification of rice flour for noodle production.   Key words: Rice flour, ginger starch, cassava starch, formulated blends, physiochemical properties.