Based On The Effect Of Bean Dregs Miniaturization On The Quality Of Rice Cakes

Steamed rice bread(SRB)structure mainly depends on the rice starch gel network structure,different from flour products,rice as raw material of pastry is difficult to form a porous structure similar with wheat bread due to the lack of gliadin and glutenin,which need to adding emulsifier,gelling agent,polysaccharide to increase its volume and space network of the porous structure.Secondly,rice starch is a rapidly digestible starch(RDS),which can easily lead to the rapid rise of postprandial blood glucose.As a kind of natural polysaccharide fiber,okara can prevent obesity,diabetes,cardiovascular disease and other health functions,and has the characteristics of natural emulsifier in the food processing process,its water and oil holding capacity and swelling force can also effectively regulate the structure of food matrix.Therefore,in this study,the okara was added to the traditional SRB making process by micro-processing(ultra-fine grinding and high pressure homogenization)to obtain a okara-SRB with better texture and lower predicted glycemic index(p GI).The effects of microrefined okara on texture characteristics,starch multi-scale structure,starch digestibility and flavor characteristics of SRB were further investigated.The main research contents and conclusions are as follows:(1)The effects of 7%,14%and 21%okara on the viscosity,fermentation gas holding capacity,texture characteristics and starch digestibility of SRB were investigated.The results showed that okara increased the elasticity and viscosity of SRB,but decreased the hardness,cohesion and chewability.The addition of okara significantly increased the amylose content,slowly digestible starch(SDS)and resistant starch(RS)of SRB,and the p GI of SRB decreased from 79.14 to 74.17-68.91by using the first order kinetic model C=C_?(1-e^-kt)to simulate the starch digestion process.The SEM results showed that the addition of 7%okara was beneficial to the formation of starch-gel porous network structure in SRB,while the addition of 21%okara made the surface of SRB rough,increased the matrix density of SRB and decreased the specific volume of SRB.XRD and FTIR results showed that proper amount of okara(14%)was beneficial to the formation of starch ordered crystal structure,while excessive amount of okara(21%)decreased the proportion of starch ordered crystal structure.Multi-scale structure of starch research reveals the okara can affect the starch gel aggregation and rearrangement of molecular chain,will further affect the different scales of the rice starch gel structure,SDS and RS,and through the physical barrier of the protein,dietary fiber and orderly crystalline structure synergistic inhibition of the enzyme activity to adjust the in vitro starch digestibility and p GI.(2)The medium-particle size and small-particle size okara obtained by ultramicro grinding and high pressure homogenization were added into SRB to investigate the effects of medium-particle size and small-particle size okara on rice slurry viscosity,fermentation gas holding capacity,texture characteristics of SRB and starch digestibility of SRB.The results showed that the smaller the particle size of okara,the higher the viscosity of mixed liquid with rice slurry.The specific volume of SRB in the two groups after micro-refining treatment was significantly increased(P<0.05).The smaller the size of okara,the smaller the hardness,viscosity,cohesion and chewability of the three groups of SRB,while the elasticity was the opposite.The in vitro starch digestibility of SRB was increased by ultramicronized medium grain okara,which was represented by the increase of RDS content.The kinetic constant(k)and p GI were increased by the first order kinetic model C=C_?(1-e^-kt)fitting.However,the starch digestibility of SRB was significantly decreased by high pressure homogenization of small-particle size okara.The contents of RDS,SDS,RS and amylose were significantly increased,and the kinetic constant(k)and p GI were decreased.The results showed that the high pressure homogeneous small-particle size okara and rice slurry formed a stable and uniform emulsion,and the viscosity and stability of the SRB were improved through the enhanced force between the water molecules.The increase of the proportion of starch crystallization zone and the increase of the physical agglomeration surface area synergistic decreased the starch digestibility.(3)Electronic nose,HS-SPME-GC-MS and ROAV analysis were used to detect the volatile components of SRB with 7%,14%and 21%okara.44,50 and 49 volatile components were detected,respectively,which were higher than those of the control group(41 kinds).The results showed that the addition of okara significantly increased the alcohol,aromatic compounds and a small amount of ester volatile components in the SRB,which together gave the SRB unique bean flavor,fruit flavor and grass flavor.Through ROAV analysis,we obtained the contribution degree and taste performance of volatile flavor components to SRB at different adding amount of okara.The results showed that Hexanal replaced Ethanol as the main key volatile compounds of SRB after adding okara,and it gave SRB oil flavor,fruit flavor and fresh flavor.