Effects Of Buckwheat Bran On The Qualities Of Steamed Bread

About 25%of buckwheat bran is produced as byproducts of buckwheat flour production.It is rich in protein,dietary fiber and flavonoids.Adding buckwheat bran will also reduce the sensory quality of food and limit its application in food industry.It is generally sold as animal feed or fertilizer due to insufficient market application.With customers’health conscious increasing,there lays an expansive market for nutritious and tasty pre-mixed steamed bread flour product to develop.In this study,buckwheat bran was crushed and sieved into five different particle size streams to research the influence of granularity on the quality of steamed bread.Mixed buckwheat bran with wheat flour in different proportions.Particle sizes to explore the influence and correlation of rheological properties and steamed bread application.And we studied the difference of chemical composition.Usage of NI GI 20 equipment was applied to predict its GI values.Based on the results,dough improvers are used to improve buckwheat bran steamed bread for taste and appearance and develop a pre-mixed steamed bread flour product.Major research contents and results include:（1）Physical and chemical properties of buckwheat bran with different particle sizes and rheological characteristics of wheat flour compound were studied.The results showed that the protein content,dietary fiber content and carbohydrate content of buckwheat bran in different granularity ranges were 24.3%～42.9%,16.0%～21.5%and10.2%～33.9%,respectively.And the total flavonoids,rutin and total phenols in the particle size range of 140μm～375μm were significantly higher than others.Mixed buckwheat bran with wheat flour in different proportions,after more than 15%,the data changed obviously.With the same amount of buckwheat bran,particle sizes of buckwheat bran decreases.The peak viscosity decreases first and then increases,and the dough stability time,total volume of CO₂ produced and retained,lactic acid SRC first increase and then decrease.（2）Effects of buckwheat bran with different particle sizes on the quality of steamed bread when the substitution level is 15%,and the correlation between steamed bread quality and the physicochemical properties of buckwheat bran flour-wheat mixed flour were studied.After adding buckwheat bran,there were some problems in steamed bread,such as lower specific volume,rough structure,skin-core separation,lower elasticity and sticky tooth feeling.And appropriate particle sizes of buckwheat bran can reduce the negative effect on the quality of steamed bread,140μm～250μm have higher acceptance in steamed bread.By correlation research,sensory score of buckwheat steamed bread was negatively correlated with water SRC,and specific volume was positively correlated with lactic acid SRC and CO₂ gas volume.（3）By adding wheat gluten,DATEM and xylanase to improve the quality of steamed bread,and its improvement effect was studied.The best ratio of improver was obtained by orthogonal experiment,and high-quality buckwheat bran steamed bread was made.The best improvement scheme is to add 3%gluten,0.4%DATEM and 20mg/kg xylanase through orthogonal optimization.Xylanase has the greatest influence on the quality of buckwheat bran steamed bread,followed by DATEM and gluten.SEM observations show that the gluten network became continuous and complete after improvement.NMR analysis showed that the content of deep combined water in the improved buckwheat bran dough increased and the content of semi-combined water decreased.Addition of improvers promotes the transformation from semi-combined water to deep combined water.（4）Based on above,a pre-mixed steamed bread flour was developed,and the nutritional components and shelf life of the pre-mixed steamed bread flour were studied.Research results show that this experiment successfully developed pre-mixed steamed bread flour.It contains 15.9%protein,1.5%fat,3.6%dietary fiber and 68.9%carbohydrate.Its rutin content is 3.5 times of buckwheat flour.Shelf life of pre-mixed flour can reach 180 days.Prediction by in vitro digestion,the GI of buckwheat steamed bread is 62.8,while that of the control（100%wheat flour steamed bread）is 84.0,which is more suitable for consumers than wheat flour steamed bread.