Formation Ang Quality Properties Of Wheat Starch Through High Pressure Mutation Breeding Method

In order to understand the starch dynamic synthesis in the process of grain filling andquality characteristics of wheat grain induced by high-pressure, the dynamic accumulationof starch content and starch characteristics were studied.wheat variety Yanzhan4110wastreated with high-pressure (120MPa) for8hours.During the growth and maturation ofwheat plants, five mutants were selected as experimental materials,Yanzhan4110as thecontrol.Results showed as followed:(1)The wheat grain filling process is main the process of starch accumulation in theendosperm, starch accumulation is directly related to the quality and yield of wheat grain.The results of this study showed that the dynamic change of starch, amylose andamylopectin contents showed an S-shape in filling stage. Starch, amylose and amylopectincontents in filling stage increased rate showed "slow-fast-slow" trend.The maximumstarch,amylose and amylopectin content accumulating rate appeared on15-20d afteranthesis.The starch, amylose and amylopectin contents of gaoya2and gaoya5were higherthan the control, while that of gaoya9was lower than the control at mature stage. Starchcontent of gaoya2and gaoya9was80.99%and73.5%, respectively, while the control was77.38%(P<0.05). There were obvious differences between samples of Total starch, amyloseand amylopectin accumulation rate.The fastest period of starch, amylose and amylopectinaccumulation rate had appeared in15~20d after flowering. In this stage,the control peakrate of total starch and amylopectin were higher than other samples,the control peak rate ofamylose was lower than Gaoya2、Gaoya5.(2) Using scanning electron microscope to observe the microstructure of wheatstarch induced by high-pressure during the grain filling process showed that A-type starchgranules appeared in5day after flowering,and A type starch granule volume continued toincrease in the whole period of grain filling.Some protrusions had begun to appear onsurface of some A type starch which meaned that B type starch grains appeared in10dayafter flowering.A type starch granule size and number continued to increase,while largesstarch granule surface projections continue to split the B type starch.25day later, theprojection on the A-type starch granules differentiation basically stopped, A, B-type starch granules quantity, volume tended to be stable and consistent which the A type starchgranules liked round cake and B type starch granules were spherical.The granule size distribution trend of different wheat starch were similar, showingtrinodal peak distribution that the peaks appeared at2.6μm,19.95μm and138μm. A typestarch grains (>9.8μm) volume accounted for72.23%~76.51%, indicating a largecontribution to the total volume of starch grains. The volume percentage of different wheatgrain induced by high-pressure were significant difference.(3)The properties of different wheat grain induced by high-pressure were studied. Theresults showed water segregation rate of starch were between51%to60%.Watersegregation rate of Gaoya5and Gaoya11were minimum. At the temperature of90℃solubility of different samples starch were not significant (P<0.01), solubility of starchwithin3.67~4.60, solubility of Gaoya2, Gaoya3significantly lower than the control(P<0.05).Starch paste retrogradation volume of different wheat induced by high-pressurewere decreased with time. In the first6h, sedimentation volume fastest changed, thensedimentation volume changed slowly. Gel texture parameters of different samples showedsignificant difference.Gaoy11and control group were higher then others, while Gaoya3parameters were the lowest.(4)Selected Bmax－Aminas the response value, Design-Expert software was used tooptimize the isolation process. The optimum isolation conditions were as follows: drawingthe volume of suspension was12.40mL; precipitation temperature was22.40℃;precipitation time was82minutes. Under these conditions, the model predicted andexperimental value of Bmax－Aminwere7.015μm and7.128μm. Beside, A-type starchparticle size distributed in the range of11~34μm and B-type starch particle size within3~10μm.The optimized process condition are stable and practicable in manufacture.