| In this study,five varieties of millet starch were selected as the research object.The basic components,microstructure,viscosity,transparency,solubility and swelling potential,coagulability,freeze-thaw stability and visible spectrum of starch iodine complex of millet starch were studied by alkali extraction.The gel properties of 5 kinds of millet starch were studied by scanning electron microscope(SEM),and their texture characteristics,water holding capacity and gel force were measured.Three different processing methods were selected to treat starch and determine its basic characteristics.The results showed that the protein content of millet was 8.71% ~ 9.79%,starch was 60.42% ~72.94%,amylose was 18.98% ~ 28.98%,amylopectin was 70.97% ~ 80.91%.Millet starch granules are irregular spherical,some of them have depressions on the surface,with a diameter of 4-16 ? M.The transparency of millet starch ranged from 12.78% to 16.61%.In terms of retrogradation,"Changnong 40" starch paste was the fastest and "Changsheng 13" millet starch paste was the slowest.Among the five kinds of millet,"Jingu 21" has the highest solubility and the largest expansion volume,"Changsheng 07" has the lowest solubility and "Changnong 40" has the smallest expansion volume.Among the five varieties,the rate of water separation was 67.74% ~ 76.27%,the stability of Jingu 21 was poor,and that of Changnong40 was good."Jingu 21" millet starch has the highest gelatinization temperature,peak viscosity and disintegration value,"Changnong 35" starch has the lowest gelatinization temperature,"Changnong 40" starch has the lowest peak viscosity and disintegration value,"changnong35" starch has the highest retrogradation value,"Changnong 07" starch has the lowest retrogradation value.The maximum absorption peak of five kinds of millet starch was about 595 nm."Changsheng 13" and "Changsheng 07" starch gel had higher hardness,stickiness and chewiness.The elasticity of "Changsheng 13" starch gel was the highest,which was significantly different from that of other millet starch(P<0.05).The hardness,elasticity and chewiness of "Changnong 35" starch gel were the lowest,and the cohesion of "Changsheng 07" was the highest,and there was a significant difference from other samples(P<0.05)."Changnong 35" starch gel has clear and compact structure,and the microstructure of starch gel is relatively homogeneous.The pore size of "Changnong 40","Changsheng 13" and "Jingu21" are similar.Among them,"Chang Nong 40" has incomplete pore walls and incomplete pores.The gel surface formed by "longevity 07" gel is a continuous network structure,and the micropores are larger than other four species,and the size is different.Aggregation,uneven distribution and loose structure.The water holding capacity of the five starch gels was 87.18%~96.28%,and the water holding capacity of "Changnong 40" was the worst,and the longevity of "Changsheng 13" had the best water holding capacity.The amount of starch involved in gel formation is 51.96%~71.10%,and the proportion of hydrogen bonds is 27.52%~45.08%.However,the basic properties of different processed starch have changed.After steaming,high pressure and frying: the range of transparency and freeze-thaw stability changed,the settling speed of starch paste accelerated,the solubility and swelling volume of starch in different treatment methods were different,the absorbance value of five kinds of starch changed,but the maximum absorption peak was still around 595 nm. |
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