Analyses Of Starch And Protein Characteristics Of Wheat With Different Gluten Contents

In this study,six varieties of wheat with different gluten contents were used as research objects to study the changes of starch characteristics and their relationship with changes of protein properties in wheat with different gluten contents.The research contents mainly include: the composition,structure and physicochemical properties of starches and proteins;the composition,microstructure,gelatinization properties and rheological properties of flours.This topic has a certain statistical significance for the study of wheat quality characteristics,and it can also provide basic data for exploring the interaction between wheat starches and proteins.The starch structure,amylose and amylopectin content,solubility,swelling potential,freeze-thaw stability,pasting properties and rheological properties of wheat flour with different gluten contents were analyzed.The results showed that the crystallinity of starch in wheat flour with different gluten contents was different,but the difference was not significant.The content of amylose in wheat flour with different gluten contents increased with the increasing of gluten content in wheat flour,and the content of amylopectin decreased.The difference of the content of amylose and amylopectin leads to the difference of physicochemical properties of starch in wheat flour with different gluten contents;with the increase of amylose content,the solubility of starch decreased and the swelling potential increased;with the increase of amylose content,the freeze-thaw stability of starch decreased;the peak viscosity of the starch pasting characteristics increased with the increase of amylopectin content in starch,and the retrogradation value was highly positively correlated with amylose;the thermal stability of starch increased with the increase of amylose content.The amylose and amylopectin contents in wheat flour with different gluten contents are related to the content of gluten in wheat flour,which leads to a corresponding change in physicochemical characteristics of starch.The protein composition,molecular weight distribution,solubility,secondarystructure of gluten protein,thermostability of gluten protein,and rheological properties of gluten protein were analyzed.The results showed that there were significant differences in the four protein contents of wheat flour with different gluten contents,among which the medium gluten wheat flour(Zhoumai 27,AK58)had higher albumin content,the contents of gluten,gluten and gliadin are highly correlated with gluten protein content;wheat flour with different gluten contents have different amino acid contents,Xinmai 26 has the highest content of various amino acids,polar amino acid content of wheat flour with different gluten contents increases with gluten protein content;There was no significant relationship between solubility and hydrophobicity and gluten content of wheat flour;the secondary structure of gluten protein showed that the ratio of α-helices and random coils has correlation with hydrophobicity;the thermal stability,rheological properties and gluten content of gluten protein were showed absent Significant correlation.In order to explore the interaction of starch and protein,and the effect of starch on the quality of wheat flour,the composition and physicochemical properties of wheat flour with different gluten contents were analyzed under the same experimental conditions.The results showed that the content of protein and damaged starch increased with the increase of gluten content;the parameters of starch content decreased with the increase of gluten content;the viscosity of flour paste showed that the peak viscosity increased with the decrease of gluten content.There was no significant difference in the gelatinization temperature between high-gluten and medium-gluten wheat flour.The gelatinization temperature of low-gluten wheat flour was the highest,and the attenuation value increased with the decrease of gluten content.The interaction of starch and protein in wheat flour with different gluten contents indicates that the higher starch content,the lower gluten content,the looser the microstructure of flour,and ultimately lead to differences in physical and chemical characteristics of flour.