Improved cooking quality and reduced in vitro digestibility in germinated highland barley noodles through synergistic modification with guar gum and Na2CO3.

Abstract

This study investigated the synergistic effects of hydrocolloids (guar gum, GG; xanthan gum, XG; and carboxymethyl chitosan, CMC) and alkaline salts (Na2CO3 and NaHCO3) on germinated highland barley noodles. Hydrocolloids reduced cooking loss, breakage rate, and thermal decomposition of noodles while improving elongation, hardness, springiness, and chewiness. GG exhibited the most significant effects. The synergistic modification of GG (0.4 %) and Na2CO3 (0.4 %) further optimized these properties, improving color and sensory evaluation scores. GG and alkaline salts enhanced intermolecular hydrogen bonding (OH···O), creating denser and more uniform noodles. The increases in degree of order (DO, 1047 cm-1/1022 cm-1) and degree of double helix (DD, 995 cm-1/1022 cm-1) indicated a more ordered structure. Resistant starch content increased from 18.27 % to 30.23 % and predicted glycemic index (pGI) decreased from 71.09 % to 58.15 %, offering benefits for diabetic health. This study improved the cooking quality and reduced the pGI of traditional noodles and broadened the application of germinated highland barley in noodle production.