Processing Characteristics Of Tartary Buckwheat Bran Flour And Its Application In Wheat Products

Tartary buckwheat（Fagopyrum tataricum L.）,also known as Tartar buckwheat,belongs to the dicotyledonous crop of buckwheat of Polygonaceae.It has high nutritional value and medicinal value,and is a crop for both medicine and food.Tartary buckwheat bran is a by-product of Tartary buckwheat processing,which is rich in a variety of nutrients,but it is mainly used in feed production,resulting in great waste,so comprehensive development is urgent.In this study,Tartary buckwheat whole flour（TBWF）,Tartary buckwheat bran flour（TBBF）and Tartary buckwheat core flour（TBCF）were prepared from Tartary buckwheat.The chemical composition and particle characteristics of TBBF-wheat flour（WF）were compared,and the effects of TBBF on the appearance,structure and starch digestion of steamed bread were clarified.At the same time,the effect of moisture-heat treatment on the physical and chemical properties of TBBF was analyzed.On this basis,with TBBF as particle emulsifier,the food grade Pickering high internal phase emulsions（HIPEs）were constructed,and their structure and properties were characterized,which were used as a butter substitute for cake production.The main research contents and conclusions are as follows:（1）TBWF,TBCF and TBBF were prepared respectively,their compositions and physicochemical properties were compared,and the processing characteristics of TBBF-WF mixed flour were systematically investigated.It was found that TBBF had higher protein and rutin contents,so its antioxidant activity and dough rheological properties were obviously superior to those of TBWF and TBCF.When TBBF was mixed with WF,its weight proportion in the blend(W_bran)had a significant effect on the dough rheological properties.When W_bran was 30%,the dough had the optimal mixing tolerance,and when W_bran exceeded 30%,it caused dilution effect,weakening the gluten network.With the increase of W_bran,the color of the steamed bread developed by the TBBF–WF blend gradually darkened（L*decreases）and yellowed（a*and b*values decrease）,the specific volume declined,and its hardness,gumminess,and chewiness ascended gradually.The appropriate addition of TBBF(W_bran=10%and 30%)was beneficial to cell diameter and volume of steamed bread,but the further rise of W_bran would destroy its gas retention ability.The predicted glycemic index（p GI）of steamed bread declined significantly with the increasing W_bran.（2）The effects of moisture-heat treatment conditions on the physicochemical properties of TBBF were investigated.The dough rheological properties of moisture-heat treated TBBF（MTBBF）-WF mixed flour were studied,and its application in steamed bread processing was evaluated.The optimum conditions of moisture-heat treatment were determined as following:Moisture content 43.6%,temperature 123.3℃,treatment time 2.1h.The addition of MTBBF had a significant effect on the dough torque curve and parameters.With the increase of MTBBF weight ratio(W_MTBBF)in the mixed flour,the water absorption of dough increased gradually,and the protein weakening degree decreased at first and then increased.When W_MTBBF=30%and 40%,the doughs had better kneading resistance.With the increase of W_MTBBF,the L*value of the steamed bread decreased gradually,the a*value increased gradually,the b*value increased at first and then decreased,and the specific volume decreased gradually.In addition,the hardness,gumminess and chewiness of steamed bread increased gradually with WMTBBF,but its elasticity,cohesion and resilience decreased gradually.When W_MTBBF exceeded 20%,the fineness of the internal structure of steamed bread increased.Sensory evaluation results showed that the obtained steamed bread could obtain similar quality and pleasant appearance to traditional steamed bread when W_MTBBF=20%.（3）The ability of TBWF,TBCF and TBBF to directly construct Pickering HIPEs was systematically investigated.The results indicated that these flours had a similar appearance and size distribution,but TBBF was rich in proteins,lipids,and rutin.As a result,its hydrophobicity and ability to reduce interfacial tension were superior to TBWF and TBCF.These Tartary buckwheat flour（TBFs）could fabricate HIPEs with an oil phase volume fraction（φ）of 80%,but when the addition amount（c）was constant,the HIPEs developed by TBBF exhibited the smallest droplet size and the highest gel strength.Microrheological analysis also showed that increasing the amount of TBBF not only contributed to the gel strength but also accelerated the gel formation.Among these TBFs,TBBF had the best performance.Sunflower oil-based HIPEs based on TBBF（φ=80%,c=5%）could replace butter to prepare cake.With the increase of the amount of butter replacement(W_BS),the color of cake darkened,and the specific volume and quality loss gradually increased.When W_BS≤30%,the change of cake texture and internal texture structure was not significant.When W_BS≥50%,the roughness of its internal texture increased.However,the DPPH and ABTS scavenging activities and total phenol content of cake increased with the increase of W_BS.