Research On The Formation Mechanism Of Wheat Flour And Buckwheat Flour Mixed Dough And Buckwheat Bread Baking Properties

Buckwheat was a kind of material which was rich for starch,high content of unsaturated fat,high protein crops,and has a high nutritional value.However,buckwheat has no gluten structure,so it's hard to form a dough.This work aims to optimize the technical and formula of buckwheat bread by using sweet buckwheat flour and high gluten wheat flour and 30% buckwheat 70% wheat mixed flour by electronic nose and GC-MS techniques to classification and quantitative the volatile substances.Compositions and molecular structures of starch and protein from wheat and buckwheat and mixed flour and the formation mechanism of mixed flour dough which were from the point of molecular specificity were studied by scanning electronic microscope,Fourier transform infrared spectrum,X-ray diffraction,differential scanning calorimetry,rapid viscosity analyzer and so on.The work may pave the way to buckwheat flour food processing.The main conclusions are as follows:1.Use sweet buckwheat flour and high gluten wheat flour and 30% buckwheat-70% wheat mixed flour as raw material,and adopt the Osbrone method to separate protein components.The results shows that: there are four types of protein in wheat flour while only three kinds in buckwheat,so buckwheat lack of prolamine which is the formation content of gluten,and the content of glutelin in wheat flour higher than buckwheat flour.Meanwhile buckwheat has high albumin in buckwheat,these are bad for formation of dough.There are more sulfur-containing amino acid in wheat protein than in buckwheat protein,and it's the first limit amino acid in buckwheat flour.The disulfide bong and sulphur content in buckwheat glutelin much larger than wheat glutelin.In the condition of powder,most of the content protein are made of ?-sheet and ?-turn,except there are part of ?-helix in buckwheat glutelin and part of ?-helix and random coil in mixed flour globulin,protein structure relatively complete.According to DSC,the endothermic of the content protein in mixed flour all greater than buckwheat and wheat,which is bad for the formation of dough.According to SEM,wheat prolamine has strong gumminess,but albumin & globulin & glutelin have loosely structure.Four proteins in buckwheat all have loosely structure;Buckwheat content protein has higher degree of crystalline than wheat content protein,the degree of crystalline in mixed flour in the middle of buckwheat and wheat.The mixed flour has higher nutritional value,and AAS & CS all higher than wheat flour.The formation mechanism of buckwheat dough was preliminarily illustrated by the test of the protein indexes.2.Use sweet buckwheat flour and high gluten wheat flour and 30% buckwheat-70% wheat mixed flour as raw material,and adopt the Osbrone method to separate starch.The results shows that wheat starch are made of two kinds of particle,while buckwheat starch present the polygon,and the starch particle is small.All of the flour and starch belongs to A type diffraction,buckwheat starch has the higher degree of crystalline than wheat starch.Buckwheat starch has higher Peak viscosity,Trough viscosity,Breakdown,Final viscosity,Setback,gelatinization temperature and heat enthalpy than wheat starch.Buckwheat starch has lower transparency and smaller solubility than wheat starch.Compared to wheat starch and buckwheat starch,mixed starch has the worst dense degree,the highest crystallinity degree,the largest absorb quantity of heat when the crystal disintegration,the most hardest gelatinization properties,the highest enthalpy value and the slowest growth of solubility,swelling powerin in high temperature compared with singlestarch.3.Use the sweet buckwheat flour and high gluten wheat flour as raw material,the buckwheat bread formula optimization is that: according to the mixed powder 100 g meter,and the dosage of sweet buckwheat and high gluten wheat is 30:70,with 1% salt,1.5% yeast,2%milk powder,6%cooking oil,5%White granulated sugar,65%water as basic formula.The formula of quality improver for buckwheat bread was 0.03% TGase,15 ppm GOD,0.5% zein,4% wheat gluten.According to the formula,the hardness of the buckwheat bread which were made according to the formula optimization is 1279.06 g,and the bread volume is 868.8mL,the sensory score is 86.77 and raise 18.27 than the original buckwheat bread.4.GC-MS and electronic nose techniques were adopted to analysis the three(100% buckwheat,100% high gluten wheat,30% buckwheat+70% high gluten wheat)bread volatile components.The results shows that: 54 kinds of volatile aroma composition were detected.And Nonanal,1-Propanol,3-(methylthio)-,Styrene all and part of acid ester are unique ingredients of buckwheat special flavor.According to Principal component analysis by electronic nose,three kinds of bread volatile flavor difference is obvious,and electronic nose techniques can distinguish the three kinds of bread easily.