Effect of Purple Yam Flour on Rheological Properties of Dough and Texture Attributions of Noodles

Objective:Affections of purple yam flour addition on farinogram quality, pasting properties, tensile properties of dough, quality of noodles. The results showed that water absorption rate was increased with increasing content of purple yam flour. The formation time 5.3 min of the dough was maximum with the addition of 15%, which increased 39.5%. When the addation of purple yam flour was 10%, the dough stability time was 3.5 min, decreased by 40.7%. The addition of purple yam flour decreased dough stretching energy and extensibility. The extensibility of the dough with the addition of 25% reached the minimum when proofing time were at 45, 90 and 135 min. Adding purple yam flour could bring down the pasting temperature, viscosity and setback. The final viscosity and setback reached the minimum at the addition of 25%, while the breakdown was maximum. The hardness, gumminess, chewiness, resilience of the noodles reached the maximum at 15% of the addition of purple yam flour, but the addition of purple yam flour had no significant (p>0.05) effect on the springiness of the noodles. With the increase of the purple yam flour, L^* value of the noodles was significantly (p<0.05) decreased. And the score of sensory evaluation was higher when addition of purple yam flour was 15%. The purple yam flour addition had significantly farinogram quality, pasting properties, tensile properties of dough, quality of noodles. The optimum addition of purple yam flour was 15%. This study could provide some theoretical basis for the processing of yam purple flours.