Buckwheat noodles processing with higher ratio of buckwheat flour is very challenging while using conventional noodle processing techniques. The mechanism of how extruded buckwheat flours can increase the addition ratio, modify the noodle cooking, and eating qualities were explored. The molecular structures of extruded buckwheat flours with different dynamic viscosities were analyzed using size-exclusion chromatography, and the water status/distribution, morphologies and starch/protein distribution of buckwheat noodles with raw or extruded buckwheat flours (RBN/MBNs) were investigated using low-field nuclear magnetic resonance, scanning electron microscopy and Fourier transform infrared spectroscopy microscope. MBNs showed lower breakage ratio, higher hardness, elasticity, and total sensory score than those of RBN. In addition, medium-dynamic-viscosity extruded buckwheat flour contributed to a continuous gluten network and even starch/protein distribution of noodles, with better cooking and eating properties. Extruded buckwheat flour with dynamic viscosity higher than 7.37 Pa s functioned as adhesives, which can hold starch granules and other components within flours together.
Keywords: Buckwheat noodle; Dynamic viscosity; Extrusion; Molecular structure; Starch/protein distribution.
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