| As Chinese traditional staple food,noodles market capacity is large,but homogeneous competition is fierce.With the improvement of people ’ s living standards,high-quality noodles are favored by consumers.The production of high quality noodles can not be separated from suitable wheat flour.At present,China lacks tailored flour standards for noodles,which seriously restricts the improvement of quality and efficiency of the industry.In this paper,we first conduct a comprehensive evaluation and classification of the quality of commercial noodles,and determine its characteristic indicators.On this basis,the correlation between wheat qualities,physicochemical properties of wheat flour and noodle characteristics was analyzed,and the characteristic parameters of wheat quality that had a major impact on noodle quality were clarified.Based on the gluten network characteristics of noodles and cooked noodles,the influence mechanism of protein and starch in raw materials on noodle quality was further analyzed.The main research contents and results are as follows :(1)Thirty kinds of noodles from different brands were selected to compare their physical characteristics,cooking quality and texture characteristics.The characteristic quality indexes of noodles were determined based on correlation analysis and principal component analysis,and the comprehensive quality of noodles was classified by cluster analysis.The results showed that the physical properties,cooking quality and texture characteristics of dried noodles from market were significantly different.The color,density,cooking loss rate and chewiness were significantly correlated,and the contribution rate of the first principal component determined by them to the comprehensive quality was 40.10%.The elastic modulus,water absorption,hardness,ductility and elasticity of dried noodles were significantly correlated,and the contribution rate of the second principal component to the comprehensive quality was18.51%.The optimal cooking time and adhesiveness were significantly correlated,and the contribution rate of the third principal component determined by them to the comprehensive quality was 12.35%.According to the principal component score,the noodle samples can be divided into high,medium and low categories.The correlation coefficients between the comprehensive score and each index were : chewiness 0.927,ductility 0.769,density 0.798,color-0.737,elastic modulus 0.599,cooking loss-0.610.In conclusion,the color and density of noodles,cooking loss rate,chewiness and ductility of noodles after cooking can be used as characteristic indexes.The model calculation values based on 11 quality indicators can determine the quality rank of noodles in the Chinese market.(2)Thirty domestic mainstream wheat varieties and two Australian wheat varieties were selected to analyze the correlation between wheat qualities,physicochemical properties of wheat flour and noodle qualities.The characteristic parameters of wheat quality that had a major impact on noodle qualities were clarified,and the prediction model of noodle quality was established by stepwise multiple linear regression equation.The results showed that there were significant differences in the quality of 32 wheat grains,their corresponding wheat flour and noodle.Peak viscosity,setback,final viscosity,gluten index and dough extensibility of wheat flour were significantly correlated with noodle quality.When wheat flour has a strong gluten index,stronger starch gelatinization ability can synergistically improve the cooking quality and texture characteristics of noodles.For wheat flour with low gluten content and poor quality,when its starch has high gelatinization ability,it will aggravate the deterioration of texture characteristics of noodles.The prediction equations of color,optimum cooking time,hardness,chewiness and ductility of cooked noodles can explain more than 60 %of the variability.The texture characteristics of noodles is mainly affected by the two parameters of setback and gluten index.In summary,the balance between gluten strength and starch gelatinization ability is a necessary condition for obtaining highquality noodles.The multiple regression prediction equation established by using the wheat qualities and the physicochemical properties of wheat flour can better predict the cooking and texture characteristics of noodles.(3)Six typical wheat varieties were selected to make noodles.The changes of pasting and swelling characteristics in different stages from flour to noodles were compared,and the changes of microstructure and secondary structure of protein in noodles with and after cooking were analyzed.Based on the difference of gluten network structure and starch restrictive swelling,the influence mechanism of wheat flour quality on cooking and texture characteristics of noodles was clarified.The results showed that when the gluten content and index were high,the stronger gelatinization ability of starch could synergistically improve the cooking and texture characteristics of noodles.Gluten index and starch swelling power are high,but gluten content is low,gluten network stability is reduced,resulting in poor cooking and texture characteristics of noodles.When the gluten index is low,the strong gelatinization ability of starch will destroy the gluten network structure,and reduce the cooking and texture characteristics of noodles.On the contrary,the low starch swelling power has a positive impact on noodle quality.The pasting properties of starch,flour and noodle can not predict the tailored flour foe noodle.Wheat varieties with high setback and peak viscosity are suitable for making noodles.The smaller the average length and width of the gluten network of the cross section of the dough sheets and cooked noodles,the larger the branching rate,and the more dense the gluten network,resulting in the lowerβ-sheet and random coil content of the cooked noodles,the higher β-turn content,and the better texture characteristics of the noodles.The tensile properties of dough based on extensometer and the tensile properties of dough sheets based on texture analyzer cannot effectively evaluate the flour making suitability of wheat flour.In conclusion,the texture characteristics of noodles is mainly determined by the quality and quantity of gluten in raw materials and the gelatinization property of starch.The setback and peak viscosity of cooked noodles can be used as screening indexes for tailored flour for noodles.The microstructure parameters of dough sheets and cooked noodles can predict the texture characteristics of noodles processed by wheat flour. |
