Effect Of Different Polymerized Inulin On The Rheological Properties Of Wheat Dough And The Quality Of Bread

Inulin is a kind of natural dietary fiber,beneficial to intestinal probiotics,and has the function of regulating blood sugar and reducing the incidence of gastrointestinal diseases.The degree of polymerization(DP)of inulin affects its properties,and the function of inulin also varies with the degree of polymerization.Low polymerization inulin has good water solubility and water retention,and high polymerization inulin has higher viscosity and gel properties.There has been a large number of studies on the nutritional and functional properties of inulin in food,while the research on the quality of dough and bread is still remained in the preliminary stage.The research purpose of this paper is to the assessment of the different degree of polymerization system inulin effects on the rheological properties of wheat flour,the opaque property,tensile property,gelatinization properties,rheological properties and its the gluten quality assessment and dynamic rheological measurement.In addition,it is applied to flour products,taking bread as an example to study its effect on the fermentation dough and the quality of bread,which provides theoretical basis for its application and research in flour products.The main conclusions are as followed:1.Through adding different proportions of inulin in wheat flour,the effects of inulin on the quality of wheat flour,stretching,gelatinization and rheological properties,as well as the influence on the quality of bread has been studied.Inulin could obviously improve the farinograph properties,extensograph properties and other rheological properties of wheat flour.Meanwhile,with the addition of inulin,the water absorption rate of dough decreased significantly,the time of dough developing and stability were extended with the increment of inulin,and the weakening degree was also reduced.Adding inulin could increase the extension degree,stretch area and tensile resistance of dough.At the same time,inulin could significantly reduce the peak viscosity,final viscosity,attenuation value,return value of flour,and starch aging speed.The rheological results showed that the elastic modulus(G')and the viscous modulus(G'')of the dough increased significantly with the addition of the inulin.Inulin effectively improved the network structure of the dough.The fermentation volume of bread dough decreased gradually with the addition of inulin,and the effect of the addition of the inulin on the fermentation volume of the dough was greater.However,the volume of dough fermentation was decreased with the increase volume of inulin,and the reduction of bread specific volume rate showed that the initial hardness of it increased significantly,while the hardness of bread added inulin was obviously lower than that without inulin about the storage time prolonged.The results showed that adding a certain amount of inulin could reduce the bread hardness,improve the internal structure,delay the aging speed and prolong the shelf life.2.Three different DP of inulin had been got by alcohol sink and crosslinking,as DP-L(DP = 4.3),DP-M(DP = 11.37),DP-H(DP)= 19.02.Those DP of inulin were added to wheat flour with 0(as comparison),2.5,5,7.5 and 10 percent,the quality of the wheat dough rheological properties and dynamic effects on bread quality were studied.The results showed that the addition of three DPs of inulin could significantly improve the quality and tensile properties of wheat flour.With the increase of DP,the water absorption rate of dough increased significantly.The water absorption rate decreased significantly with the increase of the amount of adding.Compared with the control,the dough formation time of the flour with different polymerized chrysanthemum was significantly prolonged,and the larger the addition of the same degree of the inulin,the longer the dough was formed.With the addition of adding quantity,the stability time increased and the attenuation decreased,and the DP-M and DP-L were not significantly different from the control group.The extension of the dough,the tension ratio,the area of the curve and the maximum tensile resistance were significantly increased by adding the different polymerization degree.The results of dynamic rheological properties show that,with the addition of inulin polymerization degree and adding quantity,the G' and G'' value of the dough also increased significantly.According to the temperature scanning results,the addition of three kinds of polymerized inulin can increase the gelatinization temperature of the dough and increase the G' and G'' value of the dough.In this paper,the elasticity and viscosity of the dough can be increased by adding three kinds of polysaccharide in the dough,and the increase of each addition is more and more significant.The addition of DP-H and DP-M reduced the volume of bread fermentation and reduced the volume of bread,which did not improve the quality of bread.Moreover,the larger the amount of each addition,the more obvious the decrease of bread fermentation volume and bread ratio.The addition of DP-L can increase bread fermentation volume,increase bread ratio,delay the aging of bread and improve the quality of bread.3.The aim of this experimental work was to evaluate the effect of low DP inulin?soy lecithin?SSL and alpha amylase on the aging of the bread and bread quality.The results showed that these four kinds of additives all had certain improvement effect on bread specific volume and hardness by single factor experiment.To ptimize the processing parameters of the bread,bread hardness,specific volume and sensory evaluation were used as testing indexes by the response surface method.And the comprehensive score for the final index was used as the response value.Through the response surface analysis,the interaction between different parameters and the best parameters were received.The optimum formula of bread was with 2.78% low polymerization degree inulin,0.64% sodium stearoyl lactylate(SSL),0.0051% alpha amylase and 0.87% soybean lecithin added.By this formula,the comprehensive score of bread was 9.77,the experimental results showed that the CCD model can be used to predict the quality of bread.At the same time,the aging speed of bread was delayed and the quality of bread was improved.