Effects Of Adding Coarse Grain Flour On Dough Characteristics And Steamed Bread Quality

With the rapid development of economy and the continuous improvement of people’s living standards,coarse grains play an increasingly important role in the dietary structure.Rye,proso millet,buckwheat and pea are important cereal crops with high nutritional value.However,due to their low gluten protein content and poor palatability,their processing and utilization in the staple food industry are limited.Therefore,the application of compound with wheat in steamed bread products can not only improve the nutritional characteristics of people’s staple food,enrich the diversification and diversification of food,but also provide a new way for the production and processing of grains and industrial development.In this study,coarse grain flour was added at a ratio of 30 %.Based on the systematic analysis of the basic quality characteristics of rye,proso millet,buckwheat and pea and the physical and chemical properties of wheat-coarse grain flour,the chemical composition,pasting properties,thermal properties,rheological properties and microstructure of dough were studied.The physical properties,microstructure,texture characteristics and quality characteristics of rye,proso millet,buckwheat,pea and wheat compound steamed bread were systematically analyzed.By comprehensively comparing the quality parameters of the compound powder,the steamed bread with good taste and more nutritional value was obtained.At the same time,in order to further explore the application of proso millet in food processing and optimize proso millet with relatively low gluten protein content,the effects of the combination of proso millet and three different wheat varieties on the physicochemical properties of dough and the processing quality of proso millet were comprehensively analyzed,and the optimal combination of three wheat varieties and proso millet was screened.The main conclusions are as follows:(1)There were significant differences in the basic quality characteristics of rye,proso millet,buckwheat and pea and the physical and chemical properties of the compound powder.The starch content of buckwheat was relatively high,and the protein content of pea was the highest.The protein content of rye,proso millet,buckwheat and pea were higher than that of wheat.The combination of coarse grain flour and wheat flour improved the gluten network structure of coarse grains.The porosity of wheat-buckwheat and wheatpea dough was lower,while the porosity of wheat-rye and wheat-proso millet was closest to that of wheat dough.The free sulfhydryl content of wheat-coarse grain compound dough decreased,and the intermolecular disulfide bond content increased.The peak temperature of wheat-proso millet compound flour was higher,the enthalpy value was lower,and the peak viscosity of wheat-rye compound flour was the lowest.Compared with the storage modulus curve of wheat,the storage modulus curves of wheat-proso millet,wheatbuckwheat and wheat-pea compound flour increased with the increase of frequency,while the storage modulus curve of wheat-rye compound flour increased first and then decreased with the increase of frequency.The storage modulus of wheat-proso millet,wheat-rye and wheat-pea compound flour was higher than the loss modulus,and the loss tangent of wheat-rye compound flour increased significantly.(2)The addition of rye,proso millet,buckwheat and pea flour had different effects on the quality characteristics of steamed bread.The whiteness of wheat steamed bread was the highest,while the L* value of wheat-buckwheat steamed bread was the lowest.Among the four kinds of coarse grain steamed bread,the volume and specific volume of wheatbuckwheat steamed bread were the largest,the specific volume of wheat-proso millet steamed bread was relatively the smallest,and the ratio of height to diameter was relatively the largest.The ratio of height to diameter of wheat-buckwheat steamed bread and wheatpea steamed bread was not significantly different.The pores of wheat-rye and wheat-proso millet steamed bread are relatively larger,forming a loose and porous structure of steamed bread.Compared with other coarse grains steamed bread,the hardness of wheat-millet and wheat-pea steamed bread was relatively low,and there was no significant difference in cohesion.The four kinds of coarse grains steamed bread have different degrees of coarse grains flavor;the internal structure score of wheat-rye steamed bread was the lowest,and the internal stomatal size was different.The total score of wheat-proso millet steamed bread and wheat-pea steamed bread is relatively close to that of wheat steamed bread.Overall,for consumers,the appearance and palatability of steamed bread added with different grains may not have a significant impact,which is suitable for people to eat.(3)The physical and chemical properties of the dough were significantly different when proso millet was mixed with different wheat flour.The protein and sedimentation values of Xinong8412 were higher than those of Xinong059 and Xinong761,and the starch content of Xinong761 was the highest.Compared with the millet dough,the continuity and uniformity of the gluten network structure of the millet-wheat compound flour were significantly improved.Among the three compound doughs,SM-XN059 and SM-XN8412 had better dough structure,and the protein area and connection density of SM-XN761 dough were relatively small,and the porosity was relatively large.The content of β-sheet structure in the dough of SM-XN059 and SM-XN8412 was the largest relative to XN761.The free sulfhydryl content of proso millet-wheat dough was lower than that of proso millet dough,but the intermolecular total sulfhydryl content and disulfide bond content increased.In all dough samples within the test frequency range,storage modulus was higher than loss modulus,and the dough was mainly elastic.Compared with other compound doughs,SMXN059 dough had the highest storage modulus and loss modulus,XN8412 dough had the lowest storage modulus and loss modulus and the highest tanδ.In summary,for consumers,the appearance and palatability of steamed bread added with rye,proso millet,buckwheat and pea flour may have no significant effect,which is suitable for people to eat.The processing characteristics of proso millet flour mixed with wheat flours are better,which is more suitable for the processing of staple food products.