Influence of hydrocolloids on rheological properties of gluten free foxtail millet and quinoa biscuit doughs

Abstract

Effect of hydrocolloid type (Guar gum, Gum acacia, tragacanth gum, xanthan gum and their combinations in 50:50 ratio) and concentration (0%, 1%, 2%, 3%, 4%/100g/ f.b) on the rheological properties of biscuit doughs made from foxtail millet and quinoa was evaluated at 35˚C using a controlled stress rheometer. Biscuit dough made from wheat flour was taken as control. Addition of hydrocolloids significantly modified the rheological properties of doughs. Storage modulus (G’) was significantly higher than loss modulus (G”) in all types of biscuit doughs studied. Significantly higher G’ was exhibited by TG GG dough followed by TG and GG and least by TG XG dough. Irrespective of grain and concentration of hydrocolloids, XG has lowest G’ among the four individual hydrocolloids studied. Addition 1% and 4% of hydrocolloids increased, while 2% and 3 % decreased G’ significantly, compared to those doughs without hydrocolloids. Considering, the loss tangent, it was found that application of GGXG at 1% and 4 % in foxtail biscuit dough and TGXG 1% and GAXG at 4% concentration in quinoa biscuit dough were found to be closer to the wheat biscuit dough.