Search

Graphical abstract Highlights • Extrusion treatments greatly increased buckwheat ratio of buckwheat noodles. • More mobile water within MBNs facilitated gluten network formation. • Extruded buckwheat flours with varied dynamic viscosities behave like water or glue. • Variance in noodle eating qualities can be explained by starch/protein distribution. Abstract 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. [ABSTRACT FROM AUTHOR]

This study investigated the impact of methods of milling and improvers on the quality characteristics and nutritional properties of buckwheat noodles made from fine flour (FFN) and whole groat flour (WGFN). The FFN was found to be lighter in color with a finer and continuous structure while WGFN which has higher fiber content exhibited a coarser and disrupted pattern under scanning electron microscopy. The amount of rutin detected in WGFN was significantly higher (998.22 mg/100 g) than that of FFN (148.21 mg/100 g). Addition of gluten powder at 2–4% levels decreased the cooking loss while guar gum and xanthan gum resulted in the highest water absorption capacity. Rather than the individual emulsifiers, their combination (SSL + GMS) had a better effect on the overall quality. The contents of dietary fiber, slowly digestible starch, resistant starch, total polyphenol, total flavonoid and minerals were higher in WGFN. The most abundant essential amino acids were leucine (7.23–8.52%), phenylalanine (6.93–7.27%) and lysine (5.83–6.03%). This study confirmed the possible use of high buckwheat level (75%) in producing buckwheat noodles with enhanced nutritional profile. • Use of high buckwheat level (upto75%) in producing buckwheat noodles with improvers. • Nutr i tional profiling of buckwheat noodles from fine flour and whole groat flour. • Dietary fiber, slowly digestible and resistant starch was higher in whole groat flour noodles. • Higher amount of rutin and quercetin were detected in whole groat flour noodles. • The most abundant essential amino acids were leucine, phenylalanine and lysine. [ABSTRACT FROM AUTHOR]

Buckwheat noodles are mainly sold in the form of fresh and dried noodles in China. Among the noodles with varied proportions of extruded buckwheat flour (20% to 80%), the cooking or textural qualities of fresh and dried buckwheat noodles (FBN and DBN, respectively) were significantly different, and FBN showed a lower cooking loss and breakage ratio and were more elastic than DBN. FBN-20% showed the highest sensory score, followed by DBN-50%. The mechanisms causing the quality differences were investigated using water mobility and the internal structures of the noodles were investigated with low-field nuclear magnetic resonance and scanning electron microscopy, respectively. Compared with FBN, DBN showed a denser internal structure, which explained its higher hardness. The water within FBN and DBN was mainly in the form of softly bound water and tightly bound water, respectively. FBN with highly mobile softly bound water (longer T22) and a more uniform internal structure had a lower breakage ratio, whereas the trends of water relation with texture properties were different for FBN and DBN. The drying process and added extruded buckwheat flour together contributed to the varied cooking and textural properties. [ABSTRACT FROM AUTHOR]