The Molecular Mechanism Of Different Types Of Polyphenol Compounds Regulating The Digestibility Of Rice Starch Based On High-pressure Homogenization Environment

With the development of society and the continuous improvement of living standards,increasing attention has been paid to nutrition and health.Combining health with food and prevention has become the pursuit of human dietary life.Rice occupies an important position in the diet of Chinese residents.The digestibility of rice starch,the main component of rice,affects the digestion,absorption,and metabolism of rice food in the human body,which is closely related to nutrition and health.Due to the rapid digestion speed of rice starch,it is easy to produce a hyperglycemic response in human body,which can increase the risk of chronic metabolic diseases such as diabetes and obesity.Therefore,the effective regulation of digestibility to give starch or starch-based foods excellent nutritional functions has become one of the research hotspots in the field of food nutrition and health.In recent years,the application of food processing technology to regulate the digestibility and nutritional functions of rice starch with polyphenols has received great attention.In view of the current research status of the regulation of multi-scale structure and digestibility of starch by high-pressure homogenization and synergistic polyphenols,this paper proposed to explore the molecular mechanism of the regulation of different types of polyphenols on the digestibility of rice starch in high-pressure homogenization environment from the perspective of comprehensive attention to the regulation law and difference of the structure of polyphenols on the digestibility of starch.The research has important academic value and practical significance,which can provide theoretical basis and ideas for using processing technology to effectively regulate the digestibility of rice starch and design rice food to meet the needs of modern nutrition and healthThe multi-scale structure and digestibility of high-pressure homogenization rice starch(UHPHRS)-flavonoids/phenolic acids/stilbenes/ligands polyphenol complex was analyzed by using modern structural analysis techniques,and their correlations were revealed from the perspective of Pearson correlation analysis based on the types,structures,and additions of polyphenol.The results showed that the non-covalent interactions between polyphenols and rice starch molecules such as hydrophobic and hydrogen bonds,in the high-pressure homogenization environment,lead to the increase of the multi-scale ordered structure of rice starch,such as single helix,double helix,V-type crystallization,A-type crystallization,surface short-range ordering,nano-aggregate,etc.,thus significantly reducing the rapidly digestible starch(RDS)of rice starch and improving slowly digestible starch(SDS)and resistant starch(RS).With the increase of polyphenol addition,the more the ordered structure of rice starch,the stronger the anti-digestibility of complex was.All four types of polyphenols had this effect,among which the phenolic acids had the strongest effect and the lignans polyphenol effect had the least effect.The smaller,more flexible,more phenolic hydroxyl and carboxyl groups the polyphenols with different structure of the same type could improve the multi-scale ordered structure of rice starch.For polyphenols with large molecular volume composition and steric hindrance,the ordered structure and digestibility of UHPHRS-polyphenol complex was greater than that of UHPHRS only when the content of polyphenols was higher.The results of Pearson correction analysis showed that the ordered structure of the above-mentioned multi-scale was closely related to the anti-digestibility of rice starch,and the type,structure and addition of polyphenols could affect their primary and secondary arrangement.The effect of regulating the anti-digestibility of rice starch with different additions of polyphenols could not match the degree of formation of the corresponding ordered structure,indicating that polyphenols also participated as enzyme inhibitors in resisting amylase hydrolyzing,thus further improving the anti-digestibility of rice starch.The results of these systematic studies provided the basis and guidance for regulating multi-scale structure and digestibility of starch by using polyphenol compounds in food processingBased on the perspective of in vitro experiments,the digestion kinetics of the UHPHRS-polyphenol complex and its inhibition of ?-amylase activity,glucose dialysis retardation index(GDRI),sodium cholate adsorption capacity and ·OH radical scavenging capacity were discussed.The results showed that the polyphenol complex effect in high-pressure homogenization environment significantly improved the nutritional function of rice starch,and exhibited a positive correlation with polyphenol addition.The effect of similar structure polyphenol compound on nutritional function was consistent with the trend of anti-digestibility,while the effect of different types of polyphenol compound on nutritional function was not consistent with the change trend of anti-digestibility.It also showed that the nutritional functions of UHPHRS-polyphenol complexes were not only affected by the digestibility of starch,but also closely related to the physiological activity of polyphenols themselves.The obtained responsiveness between the digestibility and nutritional function of the UHPHRS-polyphenol complexes could provide reference data for further study of the effect of starch and polyphenol interaction on its nutritional function in food processingCatechins(CC),caffeic acid(CFA),resveratrol(RA),and Magnolol(MN)representing the four types of polyphenol maternal structure,were further selected as the research objects,and density functional theory was used to analyze the dominant modes and differences of the interaction between starch and polyphenol molecules in four UHPHRS-polyphenol complexes The results showed that the interactions between the four polyphenols and rice starch molecules were all non-covalent,in which hydrogen bonds played a leading role.Besides,phenol hydroxyl oxygen atom was the main binding point of polyphenol molecule as a hydrogen bond subject,hydrogen atom was the main binding point of polyphenol molecule as hydrogen bond to the body,and the absorption electron niobium base on CFA was the main action point to form strong hydrogen bond.Polyphenols improved the anti-digestibility of rice starch by destroying the hydrogen bonds in C2-OH,C3-OH,C4-OH and C6(C'6)-CH2OH molecules to denominate and recombine starch molecular chains to form a new ordered structure.The hydrogen bonds of the four complexes were mostly distributed on the phenol and carboxyl groups of polyphenols and the hydroxyl groups of glucose dimers.Van der Waals forces were mainly distributed in the spatial regions where polyphenol molecules and glucose dimers were in contact with each other.The strong space steric hindrance effect was mainly concentrated in the spatial region in the polyphenol benzene ring structure and the glucose ring structure.The four hydrogen bonds between polyphenols and glucose dimers had medium-strength hydrogen bonds and weak hydrogen bonds,respectively.The medium-strength hydrogen bonds were mainly electrostatic attraction,and the weak hydrogen bonds were combined by electrostatic attraction and dispersion attraction,the order of hydrogen bond strength was:CFA>CC>MN>RABased on the above research results,the molecular mechanisms of different types of polyphenols regulating the digestibility of rice starch in a high-pressure homogenization environment were established.It was believed that the non-covalent interactions between polyphenols and starch molecules through hydrophobic force and hydrogen bonding and other non-covalent interactions lead to the rearrangement and aggregation of starch molecular chains and stacked to form a specific ordered structure domain.Meanwhile,part of the polyphenols in the amorphous region during the digestion process were dissociated as enzyme inhibitors.The above two synergistic effects could resist the degradation of amylase and realize the regulation of the anti-digestibility of rice starch.However,this regulation effect was restricted by the molecular structure of polyphenols.Therefore,polyphenols with different types or similar structures could be used to precisely regulate the digestibility of starch,which will enrich the basic theory involved in the regulation of digestibility of starch by polyphenols.