| As an important renewable resource,starch has a wide range of uses and potential applications.However,native starches show insoluble in cold water,high susceptibility to retrogradation,lack of heat resistance,acid resistance and processing tolerance,which greatly limits its widespread application.Sorghum is a better starch resources,but the structure and properties is an important factor affecting the quality of the food.and for further processinging and utilization of sorghum.Ultra high pressure(UHP)processinging is an effective way use physically modified to develop the starch resources.In this paper,a method for preparing sorghum starch,sorghum optimize the ultrasonic assisted extraction of pigment technology,through to protein and fat,get sorghum starch;sorghum starch suspension(20%)was submitted to different pressure levels treatment for 20 min,and changes in the structure and morphology properties of starch were investigated.The main results indicated as follow:1.The optimal extraction conditions of pigment were ethanol concentration of 50.76%,ultrasonic power of 500.64W,material-liquid ratio of 1:16.72(g/mL).Under the optimal conditions,the maximum extraction rate of pigment was 54.26%;fter extraction of proteins and fats then get sorghum starch samples.Using a scanning electron microscope(SEM),and X-diffraction verified the reliability of the sorghum starch extraction processing.2.Compared with the native starch,Sorghum starch after pressure treatment changed significantly.high pressure increased amylose content of starch after treatment,reducing amylopectin content;UHP changed the particle morphology of sorghum starch,120?480MPa sorghum pressure treated starch also to maintain the original shape,The treatment of starch suspension with pressure at 600 MPa resulted in starch granule morphology was significantly undermine each other to form a weak bond between the particles of the gel structure;X-ray diffraction studies showed that the UHP treatment converted sorghum starch that individually displayed the A-type to the B-type-like pattern.3.Light transparency of sorghum starch paste decreased after UHP treatment.The UHP-treated increased the analysis of water,water absorption of starch increased after UHP treatment with increasing time The treatment of starch suspension with UHP resulted in a significant decreace of solubility(50?90 ?)and swelling power at high temperature(70?90 ?),but opposite trends were found for sorghum starch at low temperature(50?60 ?)in.swelling power.;pressure treatment increased the occurrence of sorghum starch retrogradation trend,indicating that high pressure treatment increase the rate of aging of starch at low temperatures and room temperature.4.The Rapid Visco Analyzer(RVA)viscograms of sorghum starch exhibited an increase in peak time,and pasting temperature,,However,the pressure of 120?360MPa improved the peak viscosity and breakdown,reducing the trough viscosity,but peak time there is no change.Peak viscosity and trough viscosity of sorghum starch were decreased in the pressure of 480MPa and 600MPa.Texture profile analysis(TPA)revealed that UHP treatment changed the textural properties of sorghum starch,TPA parameters of starch gels such hardness,adhesiveness,springiness,cohesiveness,gumminess,chewiness andresilience were found to be lower after UHP treatment. |
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