| Rice is one of the main food crops in China,and its biological value is relatively high.The development of rice bread is of great significance in baked goods.In this paper,the modified rice flour was added to the mixed powder for the research of pre-gelatinization and extrusion recombination technology.The rheological properties,gelatinization properties and thermalmechanical properties of the improved rice-surface mixture powder were studied by using MCR102 rheometer,RVA rapid viscometer,Mixolab mixing experiment instrument and low field nuclear magnetic resonance analyzer.The quality of rice bread was determined by texture analyzer and color difference analyzer,and the optimal pre-gelatinization conditions and extruded expansion conditions were obtained,as well as the influence of the addition amount of extruded rice flour on the baking quality characteristics of improved rice-flour mixed dough and rice bread,It provides the corresponding basis for the development and production of rice bread.The results show that:(1)The rheological properties of mixed dough with rice flour under different pregelatinized conditions were measured.The process parameters of pre-gelatinized rice flour production were as follows:the gelatinization temperature was 80℃,the gelatinization time was 3 min,the ratio of powder to water was 1:2,and the mass fraction ratio was 50%.Under these conditions,the viscoelastic ratio of the dough was close to that of pure wheat dough.The hardness and chewiness of the fast fermentation method were lower than those of the single fermentation method,which were 296.67g and 292.80g,respectively.On the basis of the pregelatinization process,a proper amount of CMC could be added to prepare the pre-gelatinized rice bread with a better comprehensive score.Compared with WBthe hardness decreased by 5.79%and the elasticity increased by 6.25%.(2)The quality of the improved mixed bread with extruded rice flour added under different extrusion conditions was determined.Through single factor experiment,orthogonal optimization,specific volume measurement and sensory score analysis,the optimal extrusion conditions of rice flour were determined as follows:extrusion temperature 140℃,material moisture content 18%,screw speed 180 r/min.The specific volume of bread reached a maximum of 4.76,increasing by 19%.The WAI,WSI and gelatinization degree of extruded rice noodles increased firstly and then decreased under different extrusion conditions,but were higher than those of ordinary rice noodles.(3)The batter characteristics of the improved mixture with extrudated rice flour were significantly changed,and there were significant differences in peak viscosity,minimum viscosity,disintegration value,final viscosity,recovery value and gelatinization temperature(p<0.05).The peak viscosity,minimum viscosity,disintegration value,final viscosity and recovery value of the improved mixture were reduced to 723.67cP,518.67cP,205.00cP,1015.67cP and 497.00cP,and the gelatinization temperature was increased to 89.63℃.The addition of extruded rice flour significantly increased the water absorption rate(WA)of the mixed powder,while the formation time(DT),stability time(ST),C2,C3,C4 and C5 values were all decreased.Compared with wheat flour,WA increased by 6.17%,DT decreased by 74.66%,and ST decreased by 84.72%.When the extruded extruded rice flour was added 30%,the hardness of the modified mixed flour reached the minimum value of 420 g,which was reduced by 55%,and the cohesion reached the maximum value of 1.41.Improved with the increase of extrusion rice noodles,mix flour dough elasticity did not differ significantly(p<0.05),extrusion rice flour add to a certain extent,reduce the improved mixed flour dough T21 values,but values T22 change was not significant(p<0.05),of which the T22 took the largest peak,improved mixed flour dough mainly liquidity centring weakly bound water.Compared with wheat flour,the peak area of strong bound water decreased by 18%,which reduced the content of strong bound water in the rice flour.(4)When the added amount of extruding rice flour was 20%,the specific volume of bread reached the maximum,which was 5.22.The maximum hardness and chewability of bread were 148.67g and 162.07g when the supplemental amount of extrudated rice flour was 0%,and the minimum hardness and chewability were 46.67g and 46.56g when the supplemental amount of extrudated rice flour was 20%and 25%,respectively.The elasticity of rice flour bread decreased from the highest 0.91 to the lowest 0.84,which decreased by 7%.When the supplemental amount of extruded extruded rice flour was 5%,the recoverability reached the highest value of 0.54,and when the supplemental amount of extruded extruded rice flour was 30%,the recoverability was significantly decreased(p<0.05),and the lowest value was 0.39.The brightness of bread crust was decreased by about 10 values with the addition of extruded rice flour,but the L*of bread crust had no significant difference when the addition amount of extruded rice flour was 10%-30%(p<0.05).Meanwhile,the brightness of bread crust was increased and the color of bread crust became whiter.The whiter color of bread crust was the whiter when the addition amount was 20%.The highest sensory score was obtained when 20%extruded rice flour was added.The optimal fermentation time of improved mixed flour bread was 1 h.Compared with wheat bread,the specific volume,color difference and texture characteristics confirmed that the addition of HPMC and extruded rice flour in the base formula can significantly enhance the texture of rice bread. |
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