Study On The Effect And Mechanism Of The Buckwheat Noodle Quality By Extrusion

Although buckwheat has an important nutrition and healthcare function, it is a gluten-free cereal. Therefore, the production of buckwheat flour products is restricted. The extrusion processing technology is an effective way to develop buckwheat food, because it can significantly increase the amount of buckwheat flour added in the final products, make full use of the healthcare function of buckwheat, and meet people's demand for nutrition and healthcare. With the composition changes, physical and chemical properties and molecular structure of buckwheat flour and starch in the extrusion process as the research object, this paper analyzed the relationship between extruded buckwheat flour and starch properties and extrusion process parameters and noodle quality, and described the mechanism to affect the buckwheat noodle quality by extrusion, thereby providing a theoretical basis for deep processing and improvement of buckwheat and gluten-free cereal food. The main results were as follows:Research on the differences between buckwheat starch, wheat starch and rice starch showed that tartary buckwheat starch granule structure was irregular and concave, its gelatinization enthalpy, RVA viscosity, gel hardness and chewiness were less than 20% of the rice starch and wheat starch. In addition, the variation coefficient of total starch content of five different varieties of buckwheat starch was 2.73%, and the variation coefficient of amylose was 24.18%.The study on the impact of extrusion modification on the physical and chemical properties of buckwheat flour and starch showed that, after extrusion, the total starch content of buckwheat was reduced, the content of amylose content increased, starch gelatinization, gel hardness, water absorption index at 30 "C and water solution index, expansion potential and cold viscosity at 30 ? and 100 ? significantly increased, and its water absorption at 100 ? decreased. Changes in extrusion temperature, material moisture and screw speed affected the physical and chemical properties of extruded buckwheat flour and starch to a certain extent, and by comparison, material moisture had the biggest impact.The study on the impact of extrusion modification on the microstructure, chemical bonds and molecular weight distribution of buckwheat flour showed that the buckwheat flour particles after extrusion were gravel-like, the whole structure became compact, and there was almost no intact starch granule shape on the surface. After extrusion, the buckwheat flour increased the C=O stretching vibration band in the vicinity of 1743cm-1, the content of small molecular starch increased, and zone II peak molecular weight in the GPC chromatogram increased. Changes in extrusion process parameters led to different degrees of degradation and resulted in changes in starch characteristic peak intensity, peak position and molecular weight distribution.The study on the impact of extrusion modification on buckwheat noodle patch, cooking and textural quality as well as microstructure showed that the noodle patch quality, cooking quality and some textural quality of extruded buckwheat noodle was improved, and because the changes in buckwheat flour properties and molecular structure enhanced the bonding degree with the gluten network, the final noodle quality was affected. When the amount of buckwheat flour added increased to 50%, although the cooking quality of extruded buckwheat noodle was poor, the quality of noodle patch, the toughness of dry noodles and the firmness of noodle was greatly improved compared to the original flour buckwheat noodle, the extrusion parameter changes had a certain impact on the quality of extruded buckwheat flour noodle, and the requirements on buckwheat flour noodle quality could be achieved by adjusting the extrusion condition to change the nature of buckwheat flour.