The Effect Of Wheat Bran Powder On The Main Components Of Frozen Dough And The Quality Of Steamed Bread

Wheat bran is a by-product of wheat flour processing,which is rich in nutritive,but nutrient utilization rate is very low.Wheat bran powder that is made from crushed wheat bran is used in food production,that can increase the utilization of food and the nutritional value of food.The application of frozen dough technology in actual production can effectively reduce inventory,and can reduce the product expiration in the sales process and improve food security.In this topic,wheat bran powder was used to raw materials,and added it to the frozen dough,and to research change of the main components of the frozen dough that starch and gluten protein system in different frozen periods.Discussion on the wheat bran powder has influenced on physicochemical properties such as transparency,viscosity and thermodynamic properties of starch and the changes of sulfhydryl,disulfide bond,subgroup,water and secondary structure in gluten protein,and to provide important theoretical basis for the application of wheat bran powder in frozen steamed bread.The main results were as follows:(1)The transparency,viscosity and thermodynamic properties of starch in frozen dough and blank frozen dough to study the effect of wheat bran powder on starch-chemical properties in frozen dough was studied.The results were as follows:Under the same freezing conditions,the transparency of starch in the blank group,the initial temperature of gelatinization,the peak temperature and the termination temperature were all higher than that of the wheat bran powder group;But the peak viscosity,the dilute value,the final value viscosity,the return value,the gelatinization temperature and the gelatinization enthalpy value were all lower than the wheat bran powder group;In addition,with frozen storage increasing,the transparency showed a decreasing trend,and the peak viscosity,dilute value,final viscosity and return value showed an upward trend.It was indicated that the addition of wheat bran powder increases the energy needed to destroy the powder structure,that resulted in the increase of the gelatinization enthalpy.And the frozen storage could lead to the transition of partially unmovable semi-confluent water to the removable semi-binding water and free water in the starch-water system,thus the thermal stability of the system reduced.(2)The different freezing storage period of wheat bran powder of frozen dough and blank in the frozen dough gluten protein thiol,disulfide bond,protein subunits,moisture migration and secondary structure index determination,observational study properties of wheat gluten powder in frozen dough gluten protein was studied.The results were as follows:In the same freezing time,the content of T21,free mercaptoprotein,no regular curl,alpha-helix,and beta-angle structure that were added to the wheat bran powder frozen dough was higher than the blank group.But the content of T22,disulphide,intermolecular ?-fold,the antiphase parallelism ?-fold and the ?-fold structure was reversed,and the wheat bran powder group was lower than the blank group.As the extension of freezing storage time,T21 and T22 all presented the rising trend.But when the frozen time reached 30 days later,the decrease trend of the combined water content of wheat bran powder was decreased compared with that in the blank group,and the water content was significantly higher than that in the blank group.Frozen storage has no effect on subunit in gluten protein.After adding wheat bran powder,the color of 100 KDa and above electrophoresis bands is generally darker,especially at 120 KDa.Because in wheat bran powder,the phenolic acid and protein combined with the oxidative crosslinking reaction,and made the partial disulfide bond in gluten protein induced to break bond and convert to free sulfhydryl group.And hydroscopicity of wheat bran powder is stronger than wheat flour,which will compete for water in the dough system,then resulting in the redistribution of water in the system and the partial dehydration of gluten protein.And the elastic-folded structure of the beta-collapse was transformed into a beta-corner and no regular curl.The frozen storage would cause the disulfide bond breaken,and the external disulfide bond of the chain would dissociate the gluten protein to different degrees and accelerated the migration speed of water in frozen dough.The addition of wheat bran powder promotes the polymerization of some low molecular weight proteins,and it forms a larger protein polymer than the separation glue.(3)The different freezing storage period of wheat bran powder of frozen dough rheology and blank frozen dough fermentation characteristics and steamed bread volume and quality and structure of the index to study wheat bran powder on frozen dough fermentation characteristics and the influence of the quality and structure characteristics was studied.The results were as follows:With frozen storage time increasing,the height of frozen dough,the amount of gas produced and the ratio of gas holding and the ratio of steamed bread were all decreased.and the hardness,adhesiveness and mastication of steamed bread showed an increasing trend.There was no significant effect on elasticity and resilience.When the frozen storage time was below 30 d,Hm and steamed bread of the blank frozen dough were higher than the frozen dough steamed bread with wheat bran powder.It was indicated that the addition of wheat bran powder would directly cause certain damage to the gluten network structure in the dough and directly affected the quality of the dough.However,as the freezing time was extended,the quality of the wheat bran powder frozen dough decreased slightly less than the frozen dough that did not add wheat bran.(4)According to correlation analysis:The addition of wheat bran powder was significantly correlated with the secondary structure of gluten protein,and there was a significant negative correlation between intermolecular position-folding,reverse parallel position-folding and beta-folding,and significantly positive correlation with non-rule crimp,alpha-helix and beta-turn(P<0.01),And was a significant positive correlation with T21(P<0.01),and was significantly negatively correlated with A21 and elasticity(P<0.01),and significantly positive correlation with texture hardness and mastication(P<0.05).Freezing storage time and T21,T22 and stalemate had very significant positive correlation(P<0.01),and the elasticity and cohesiveness had very significant negative correlation(P<0.01),and with the hardness and chewiness of significant positive correlation(P<0.05),and A21 and resilience significantly negative correlation(P<0.05);But the content of each component in the secondary structure of gluten protein was not significant.The hardness of the steamed bread was significantly negatively correlated with the reverse parallel position-folding and ab-folding(P<0.05),and was significantly positively correlated with the random crimp(P<0.05).There was a significant negative correlation between elasticity and non-rule crimp(P<0.01),and the inverse parallelism(P<0.01).