Effects Of Starch Composition And Different Waxy Genotypes On Gelatinization Characteristics Of Wheat Flour

Wheat is one of the earliest cultivated crops in the world.It is also the main food crop with the largest yield and consumption.It plays an important role in food production,circulation and consumption.With the development of economy and the continuous improvement of people’s living standards,the diversified demand of wheat market is constantly increasing,and the requirements for the quality of wheat products are correspondingly increasing.It was found that the content and composition of wheat starch had important effects on the quality of wheat products.By studying starch composition and gelatinization characteristics of wheat germplasm resources,this study revealed the influence of different starch composition on flour gelatinization characteristics,created new germplasm with different Waxy(Wx)gene composition,and studied the influence of Wx genotype on gelatinization characteristics,so as to provide new germplasm and data support for wheat quality improvement and molecular breeding.The main research results are as follows:(1)The coefficient of variation of amylose,amylopectin,total starch and branch direct ratio of 495 wheat germplasm resources was greater than 10%.The variation coefficients of amylose,amylopectin,total starch,branch to direct ratio and resistant starch were 13.77%,19.64%,13.22%,29.94% and 31.64%,respectively,in 90 wheat germplasm resources with different branch to direct ratio.Amylose was positively correlated with resistant starch,and the correlation coefficient was 0.496,while it was negatively correlated with amylopectin and the ratio of branch to direct,and the correlation coefficient was-0.447 and-0.833.(2)Amylose was positively correlated with the peak time(correlation coefficient was 0.359),and positively correlated with the final viscosity and rebound value(correlation coefficient was 0.194 and 0.261,respectively),but was not significantly correlated with the peak viscosity,low viscosity,dilute value and pasting temperature.The ratio was negatively correlated with the peak time with a correlation coefficient of-0.312,and was negatively correlated with the final viscosity and rebound value with a correlation coefficient of-0.210 and-0.263,respectively,but was not significantly correlated with the peak viscosity,low viscosity,dilute value and pasting temperature.The content of amylopectin and resistant starch had no significant correlation with gelatinization characteristics.(3)Among 290 new germplasm,19 were found to be all-waxy in 4 combinations,and 94 were found to have partial deletion of Waxy gene in 12 combinations.Six different Wx genotypes were identified(AABBDD,AAbb DD,AABBdd,aabb DD,aabbdd).AABBDD genotype had the highest amylose content,total starch content and resistant starch content,which were 22.48%,65.55% and 0.62%,respectively,while the lowest amylopectin content and branched to direct ratio were 43.06% and 1.94,respectively.aabbdd genotype had the lowest amylose content,total starch content and resistant starch content(2.19%,60.16% and 0.24%,respectively),and the highest amylopectin content and branched to direct ratio(57.97% and 27.81).Wx gene deletion had a significant effect on starch content,and the effect was 3 Wx gene deletion > 2 Wx gene deletion > 1 Wx gene deletion > wild genotype.(4)The peak and trough viscosity of aabb DD genotype were the highest,which were 2123.33 cP and 1194 cP,respectively.The peak viscosity,trough viscosity and dilute value of aabbdd genotype were the lowest,which were 1506 cP,930 cP and576 cP,respectively.Wx gene deletion had a significant effect on wheat paste characteristics,with the effect of 2 Wx gene deletion > 1 Wx gene deletion > wild genotype > 3 Wx gene deletion.Compared with ordinary waxy wheat flour,gelatinization characteristics of whole wheat flour added with waxy wheat flour with the same genetic background were significantly improved.(5)There was significant positive correlation between amylose and resistant starch and peak time in 90 wheat germplasm resources with different branch to direct ratio.The ratio of branch to direct is negatively correlated with the peak time and the final viscosity and rebound value.Wx gene deletion had significant effects on wheat starch content and whole wheat flour paste characteristics,and waxy wheat flour with the same genetic background had more significant effects on flour paste characteristics.