Mechanism Of Proanthocyanidins Regulating The Aggregation Of Gluten Proteins

In order to improve the quality and processing characteristics of wheat flour,high gluten wheat flour was used as the research object.Various analytical techniques and methods such as powdery instrument,scanning electron microscopy(SEM),ultraviolet spectrophotometer and fourier transform infrared spectroscopy were used.The effects of OPC addition and resting time on dough structure and properties were studied.The aggregation mechanism of cross-linking between OPC and gluten proteins was discussed in this paper.Through the experimental analysis we can obtain that the composition of the flour were:moisture 5.01%±0.23%,ash 0.89%±0.03%,protein79.39%±0.28%,fat 1.43%±0.05%,starch 3.20%±0.06%.The results showed that the gluten protein extracted from wheat flour is a kind of plant protein resources,low fat content and low calorie content.The total phenol content of OPC was 99.27%±0.49%.The results showed that the addition of OPC could improve the water absorption rate,formation time,stable time,bandwidth,and decrease the weakening degree of dough,the effect on stability time and weakening degree was significant.Then the flour properties of wheat flour were improved.The addition of OPC reduced the degree of hydrolysis of gluten,indicating that the protein formed a more stable structure and its effective particle size was smaller than that of gluten without OPC.The results of rheometer show that gluten protein is a typical viscoelastic material.With the increase of the content of OPC,the elastic modulus and viscosity modulus of gluten increased,which improves the viscoelasticity of gluten protein.OPC have effect on microstructures of gluten proteins.When the dough resting time is 30 min and the amount of OPC is 0.3%,the microstructures of gluten proteins show a dense network.At the same time,the content of free sulfhydryl group in gluten protein decreased and,the content of disulfide bond increased.The exchange reaction between them was the guarantee of the ordered gluten protein network,and the addition of OPC was beneficial to the formation of disulfide bonds.Making gluten protein structure became denser and denser.The decrease of free amino group is probably due to the crosslinking of hydroxyl group in phenol and protein amino group,which makes gluten protein more stable.The infrared chromatogram showed that the content of a-helix and ?-rotation angle increased in the secondary structure of gluten.It may be due to the existence of hydrogen bonds between OPC and gluten proteins,and the decrease of ?-folding is due to the interaction of hydrogen bonds and hydrophobicity.UV high performance liquid chromatography showed that the content of amino acids in gluten was changed after treatment with different OPC additions.The tyrosine content changed obviously,and the content of tyrosine decreased at first and then increased with the increase content of OPC.Further mass spectrometric analysis showed that OPC promoted the production of dityrosine.The electrophoretogram also showed that the addition of OPC resulted in significant aggregation of gluten molecules.OPC can improve dough strength,increase dough elasticity,and make wheat flour perform better in processing characteristics and quality.Because the amount of OPC and dough resting time could affect the microstructure of gluten proteins and make gluten proteins show better quality.