Abstract:
To improve the processing and nutritional properties of traditional flour products and develop novel noodle products using resistant dextrin, the effect of different proportions (0%, 2%, 4%, 6%, 8%, w/w) of resistant dextrin added into wheat flour on the gelatinization properties and thermal stability of the flour, rheological properties and water distribution of the dough, as well as the cooking and digestive characteristics of the noodles, were systematically investigated. Additionally, the microstructure of the dough and noodles with resistant dextrin was also observed. The results showed that as the amount of resistant dextrin increased, the peak viscosity significantly decreased from 1488.50 cp to 1188.00 cp (
P<0.05), and the initial gelatinization temperature increased from 53.68 ℃ to 61.01 ℃, enhancing thermal stability of the wheat flour. When the content of bound water in the dough decreased, the elastic modulus (G') and viscous modulus (G'') decreased with G'>G''. While short-range ordered structure and relative crystallinity of the starch in dough were increased. At the same time, the reduced porosity and smaller pore sizes on the dough surface were observed by scanning electron microscopy. With the addition increasing, the water absorption rate of the noodles increased, while the hardness and chewiness decreased. Compared with the wheat noodles without resistant dextrin, the addition of 8% increased the resistant starch (RS) content by 44.51% and decreased the glycemic index (GI) by 13.83%. The sensory scores of noodles with 2%~4% resistant dextrin were significantly higher (
P<0.05) than those with 6%~8% addition. In conclusion, resistant dextrin improved the gelatinization properties of the flour and the structural orderliness of the dough via competition with water and encapsulation of wheat starch granules, as well as the cooking properties of the noodles, while reduced the GI of the noodles, which met requirements for healthy, low-calorie, and high-fiber, and provided a new direction for the innovation and upgrading of noodle products, with significant economic and social benefits.