Effects of deacetylated konjac glucomannan on the pasting and rheological properties of rice flour, and the quality characteristics of extruded cooked rice noodles

Dried rice noodles made from single indica rice generally exhibit low shear force resistance and high cooking loss. This study evaluated the effects of varying levels of deacetylated konjac glucomannan (DKGM, 0.00 %–1.25 %) on the physicochemical properties of indica rice flour and the quality characteristics of dried rice noodles. Increasing DKGM content (0.00 %–1.25 %) progressively enhanced the pasting viscosity, storage modulus, loss modulus, and apparent viscosity of the rice flour system, while solubility decreased by 2.39 % at 0.75 % DKGM before increasing again. DKGM addition reduced the gelatinization enthalpy of rice flour and lowered the glass transition temperature of rice noodles. At 1.00 % DKGM, the rice noodles showed optimal quality improvements: cooking time decreased by 2.67 min, breakage rate by 8.46 %, and cooking loss by 4.17 %, while resistant starch content increased by 6.14 %. DKGM incorporation enhanced anti-digestibility and sensory scores, and reduced hardness and chewiness. Furthermore, DKGM increased short-range ordering while reducing the relative crystallinity of rice noodles. Overall, 1.00 % DKGM effectively improved rice noodle qualities and inhibited starch retrogradation. These findings provide valuable insights for the industrial application of DKGM in rice noodle production.