Effects Of Extrusion Processing On The Storage Of Bran Flour And Research Of Technological Parameters

In view of the problem of poor stability of wheat bran back to powder storage,the ordinary bran extrusion treatment is very difficult In this paper,the effects of extrusion on the swelling effect,main components,protein composition and internal structure of 3B,4B bran and wheat bran were studied.The influence on storage characteristics,dough property and finished product quality in different storage temperatures(5 °C、15 °C、25 °C、5 °C)by extrusion were studied;research the change of flavor substances about steamed bread.The results were as follows:After the extrusion treatment,the expansion effect of 3B bran was significantly higher than that of 4B bran and wheat bran,and the swelling force increased by more than 50%.The content of starch and fat decreased significantly,and the nutritional components were improved.Reducing sugar,phytic acid up and down trend are better than that of 4B bran and wheat bran;lipase enzyme rate as high as 80%;microbial sterilization rate of up to 95%.The content of free amino acids increased and the protein decreased.The content of β-folded,α-helica were decreased,β-corner content increased after extrusion,some protein subunits bands in SDS-PAGE map were degraded.The microstructure changed obviously.After extrusion,the effect of 3B bran was the most obvious.Indicating that extrusion treatment can lead to different content of starch content of bran film changes significantly.Fatty acid was used as the main evaluation index of the quality of the wheat flour in the storage condition.Under the high temperature(35 °C)storage condition,the fatty acid value of the powder was only 59.84 mgKOH/100 g when stored at 75 d after extrusion,the untreated back to the powder in the storage to 15 d,the fatty acid value has been close to the national standard 100 mgKOH/100 g,which shows that extrusion treatment is an effective stabilization technology.In the storage process,the reduction rate of reducing sugar,lipase and total phenol was significantly lower than that of untreated meal(P<0.05),and the decrease rate of fatty acid was significantly lower than that of untreated(P<0.05),the decrease of soluble protein was slightly higher than that of untreated back powder.Besides,the effect of high temperature storage on the indexes of adding powder was more significant than that of low temperature storage.The addition of extruded or untreated bran(particle size<250 μm)reduced the quality of the bran flour,but in the storage process,the quality of the powder was improved.Wet and dry gluten content,gluten index increased gradually with the prolongation of storage time,In addition to storage to 30 d.L* increased first and then decreased.With the increase of temperature,the content of wet gluten content,gluten index increased gradually;L* decreased first and then decreased,and the change minimum in the conditions of 15 °C.With the extension of storage time and temperature,peak viscosity was increased after treatment;time of untreated bran flour had no significant effect.With the time increasing,water absorption,extension degree were decreased,formation time,stability time,weakening degree and stretching ratio were increased,in the 75 d storage,bran flour quality declined.The higher the temperature,the higher water absorption,formation time and the stability time;elongation increased first and then decreased,the tensile resistance is increased gradually.Indicating that the effect of temperature on the powder significantly.It was found that the rheological properties of the dough were improved with the increase of temperature,but the quality was deteriorated.The storage time and storage temperature were significantly correlated with the sensory score,color,specific volume and texture of the steamed bread(P<0.05).The elasticity and recoverability of the steamed bread were the highest when stored at 35 d,and the hardness and chewiness decreased gradually when they were stored at 35 d,and then decreased at 70 d.Indicating that short-term storage can improve the internal structure of the steamed bread.After storage for more than 35 d,steamed bread began to deteriorate.In the process of storage,the storage of 35 d,15 °C,steamed bread specific volume was higher,quality and structure characteristics were better,sensory score was relatively high.Hydrocarbons,alcohols,and carbonyl were the main volatile substances for bran steamed bread;after extrusion,the amount of flavor substances in the powder and the content of the carbonyl group were significantly increased,and the flavor was rich and the taste was unique.