Research On Steam Explosion Treatment And Its Processing Technology For Cereal

Cereal processing industry is the livelihood industry and national health industry,which is closely related to the three rural issues,public dietary nutrition and safety.Traditional cereal processing blindly pursues precision and whiteness,which leads to over-processing of cereal,resulting in more energy consumption,serious environmental pollution and waste of resources.As people eat more refined diets,the risk of chronic disease is significantly higher.Therefore,it is of great significance to develop and eat whole grains with high nutritional value and certain health functions However,due to its rough taste and short shelf life,the promotion and use of whole grains are limited.People put forward new requirements for the technological reform and the technical improvement of cereal processing.Aiming at the industrial development problems of cereal processing,such as high nutritional loss and inadequate product palatability,on the basis of fully understanding the characteristics of cereal materials,this study put forward that increasing the pretreatment process and eliminating the adverse effects of cereal bran on processing process and product performance were the key to break through the existing technical problems of cereal processing.Steam explosion is the clean and efficient pretreatment technology,which has been widely concerned in the field of cereal processing in recent years.The thermochemical and mechanical modification of raw materials can be carried out by steam explosion under the dual action of thermochemical reaction in gas cooking stage and mechanical tear in instant explosion stage.The steam explosion treatment and its processing technology for wheat bran,wheat grain and sorghum grain were studied in this paper in order to provide a new pretreatment method and a certain technical reference for cereal processing.The main research results obtained in this paper are as follows(1)A new steam explosion stabilization method for wheat bran and reconstituted whole wheat flour was developed.Lipids in wheat bran and whole wheat flour are prone to hydrolysis and rancidity due to wheat bran contains more lipase activity,which largely affects the storage property,nutritional value and sensory quality of wheat bran and whole wheat flour The new steam explosion stabilization method for wheat bran and reconstituted whole wheat flour was developed.Steam explosion was effective in inactivating lipase and peroxidase in wheat bran under the pressure of 0.8 MPa and residence time of 5min.The effect of steam explosion on inactivating enzyme was better than that of conventional thermal sterilization(0.1 MPa,20 min).The steam explosion stabilization method can maintain the contents of protein and starch,promote the conversion of insoluble dietary fiber to soluble dietary fiber,and improve the total flavonoids,phenolics content and antioxidant activity of wheat bran extract.In addition,the accelerated storage experiments were conducted on wheat bran flour and reconstituted whole wheat flour.The content of fatty acids in wheat bran and reconstituted whole wheat flour during storage was significantly reduced by steam explosion,and the storage property of wheat bran and whole wheat flour was improved.(2)Steam explosion could improve the physical and chemical properties of wheat bran and the quality of steamed breadWheat bran has the high content of insoluble dietary fiber,which affects its bioavailability and processing performance.Steam explosion was used to improve the physical and chemical properties of wheat bran,and the effect of steam exploded wheat bran on the quality of flour,dough and steamed bread was evaluated.Soluble dietary fiber content of steam exploded wheat bran increased by 42.86%.At the same time,protein and lipid content were maintained.Compared with untreated wheat bran,water holding capacity,water solubility index,cholesterol and bile acid adsorption capacity of steam exploded wheat bran increased by 13.91%,30.77%,28.61%and 70.83%,respectively.The addition of steam exploded wheat bran had a positive effect on the texture of dough and steamed bread.When the added amount of steam exploded wheat bran was 10%,the springiness and chewiness of steamed bread increased significantly,and the hardening rate was the lowest(3)Steam explosion could improve the expansion quality of wheat branWheat bran with high content of insoluble substances is not conducive to extrusion,which leads to the low expansion ratio.Steam explosion was first used as a pretreatment method for extruding of wheat bran to improve the expansion quality Compared with untreated wheat bran extrudate,the horizontal expansion ratio of steam exploded wheat bran extrudate increased by 37.93%.The powder with finer particle size can be obtained by grinding the steam exploded wheat bran extrudate.In addition,the content of total phenolics(155.19%)and total flavonoids(108.89%)in wheat bran extrudate was significantly increased by steam explosion.Steam explosion improved the water solubility index,swelling capacity and cation exchange capacity of wheat bran extrudate.(4)A grinding process for wheat bran treated by steam explosion was establishedWheat bran with high toughness is difficult to be grinded into small particles and which leads to high energy consumption in grinding process.The grinding process of wheat bran treated by steam explosion was established.Steam explosion(0.5 MPa,2 min)can effectively destroy the dense structure of wheat bran,reduce the mechanical properties of wheat bran,and improve the yield and cell wall breakage ratios of wheat bran powder.Compared with hot-air drying treatment(105?,12 h),steam explosion can reduce the energy consumption in wheat bran grinding process to a certain content.In addition,the farinograph properties of recombinant whole wheat flour showed that steam exploded wheat bran had good processing adaptability(5)A processing technology for steam exploded whole wheat flour was establishedThe flour yield is low,the particle size distribution is broad,the lipase activity is high and the processing suitability is poor in whole wheat flour.Steam explosion was introduced into processing technology for whole wheat flour.The structure of wheat bran was destroyed by steam exploded.Steam exploded reduced the chewiness and the energy consumption of grinding process of wheat grain.Compared with common whole wheat flour,steam explosion maintained the basic nutrients and whiteness of whole wheat flour,and decreased the lipase activity.The cohesiveness,springiness and chewiness of noodles prepared by steam exploded whole wheat flour increased by 35.00%,26.00%and 25.77%,respectively(6)Steam exploded whole sorghum flour could improve the textural property and edible quality of steamed breadSorghum food has poor edible quality due to high insoluble dietary fiber and tannin content.Steam explosion was introduced into sorghum processing.The contents of insoluble dietary fiber and tannin of steam exploded sorghum decreased by 33.96%and 13.58%,respectively.And the content of resistant starch,total phenolics and flavonoids increased by 109.28%,18.92%and 39.01%,respectively The added steam exploded whole sorghum flour improved the textural property of wheat dough and the quality of steamed bread.When the added amount of steam exploded whole sorghum flour was 25%,the hardening rate of steamed bread was the lowest and the edible quality was better.