Effect of adding hydrocolloids on rheological and chemical properties of high amylose rice cultivars

Nowadays, gums are used in cereal and flour products to replace gluten by optimizing physicochemical and rheological properties. In this study, with the aim of improving the rheological properties of the dough compared to the control sample, the effect of different concentrations of guar gum, xanthan and pectin gums (0.3, 0.6 and 0.9%) in terms of weight / weight percentage based on rice flour of Nemat  and Neda cultivars was examined. Based on the results of the viscosity properties, the highest Peak viscosity is in Nemat and Neda cultivars with the addition of guar (0.9%) and the lowest Peak viscosity is in Nemat cultivar without adding gum or control sample. The results show that with increasing guar and increasing the concentration of added guar, the tendency to absorb water increases and the volumetric expansion of the dough will increase. The greatest effect on the rate of breakdown viscosity was observed in Nemat cultivar with the addition of xanthan gum and the highest rate of breakdown viscosity was observed in Neda cultivar with increasing guar (0.9%). Due to the decreasing trend on the rate of breakdown, we find that xanthan is not a suitable hydrocolloid to improve the rheological properties of rice flour paste of Nemat cultivar. The highest rate of setback viscosity was observed in both Nemat and Neda cultivars with an increase of 0.3% and the lowest rate was in the control sample. Comparison of the average of statistical data shows that the highest final viscosity in both Nemat and Neda cultivars with an increase in guar 0.9% and the lowest in the control sample. It can be concluded that increasing the gums used in this study increases the tendency of the final product or product to dry after cooling.