Effect of gluten on glycemic index of noodles and its mechanism

In order to improve the phenomenon of high blood glucose index of ordinary noodles, wheat flour was used as raw material, the effects of different proportions of gluten on in vitro glycemic index (eGI) of wheat flour noodles were researched, and the mechanism was discussed in terms of cooking properties, rheological properties, pasting properties and gluten macropolymer (GMP). The results showed that when the addition amount of wheat gluten was 1%, 5%, 10% and 15%, the eGI of cooked wheat flour decreased, and the reduction rates were 6.07%, 8.97%, 12.21% and 14.76%, respectively; The hardness, chewability, elasticity and cohesiveness of noodles increased. Besides, as the viscosity decreased, the cooking resistance increased. The toughness (P), extensibility (L) and baking power (W), gelatinization temperature, thermal stability and the GMP content were increased. The correlation analysis showed that the eGI of noodles was positively correlated with the viscosity of noodles, the peak viscosity of mixed powder, the retrogradation value and the cooking resistance of noodles, the rupture force, rupture distance and extensibility of cooked noodles were significantly negatively correlated. Besides, the eGI of noodles were significantly negatively correlated with gluten addition, Energy value W and GMP content. Scanning electron microscopy (SEM) results showed that the protein network structure was denser and wider, the degree of protein coating of starch particles increased, and the gelatinization of starch was inhibited. In conclusion, the addition of gluten enhanced the gluten network encapsulating starch particles, inhibited the gelatinization of starch, and inhibited the digestion and hydrolysis of starch through steric hindrance, resulting in the reduction of eGI after noodles cooking.