Study On The Synergistic Effect Of Rice Bran Dietary Fiber And Ferulic Acid On The Properties Of Indica Rice Starch

The research and development of whole-grain foods have received significant attention both at home and abroad,but the"stuck neck"still focused on processing the cortex of whole grains.Rice and rice products are the traditional staple foods of our country.The presence of dietary fiber and phenolic acid in rice bran may affect the properties of rice products,which is also the key to improving the quality of brown rice-based products.This paper used rice bran dietary fiber,ferulic acid,and indica rice starch as raw materials to establish two model systems:dietary fiber-starch and dietary fiber-ferulic acid-starch.The additional amount of dietary fiber in the dietary fiber-starch system was 6%and 9%.In the dietary fiber-ferulic acid-starch system,the mass ratio of ferulic acid to dietary fiber was10:1,6:1,and 3:1.Studied the effects of dietary fiber and dietary fiber-ferulic acid on the physicochemical properties and gel properties of starch and explored the interaction of molecules in the two systems.The main findings were as follows:(1)Water-soluble dietary fiber(SDF),water-insoluble dietary fiber(IDF),and ferulic acid(FA)had a significant influence on the swelling characteristics,gelatinization characteristics,thermal characteristics,aging characteristics,dynamic rheology,and temperature scanning of indica rice starch(RS).SDF or IDF increased the solubility of RS.FA decreased the solubility of the dietary fiber-starch system.SDF reduced the inflation of RS.IDF increased the inflation of RS in the lower temperature range but reduced the inflation of RS in the higher temperature range.FA reduced the inflation of the dietary fiber-starch system at lower temperatures and had the opposite effect as the temperature rises.Both SDF and IDF could significantly reduce the peak viscosity(PV),trough viscosity(TV),final viscosity(FV),setback viscosity(SV),and breakdown viscosity(BV)of starch,especially SDF.SDF could significantly increase the pasting temperature(Pa T)and peak time(Pe T)of starch,while IDF had no significant effect.FA reduced the PV and BV of the dietary fiber-starch system and increased its Pa T.FA increased the FV and SV of the SDF-RS system and reduced its TV.This trend was contrary to the influence of FA on the IDF-RS system.Both SDF and IDF increased the onset temperature(T_o),peak temperature(T_p),and conclusion temperature(T_c)of starch and decrease enthalpy change(?H).FA reduced the T_o,T_p,and T_c of the SDF-RS system,and this trend was the same as when the amount of FA added in the IDF-RS system was higher.FA increased the?H of the SDF-RS system and decreased the?H of the IDF-RS system.Both SDF and IDF reduced the retrogradation rate of starch,and FA enhanced this trend and positively correlated with the added amount.SDF and IDF changed the growth form of starch recrystallized crystals and accelerated the crystal growth rate.FA changed the growth form of the recrystallized crystals of starch in the dietary fiber-starch system and slowed down the crystal growth rate.SDF and IDF had significant effects on the dynamic rheology-temperature sweep curve,modulus value,and temperature corresponding to the peak modulus of RS.FA also had the same effect on the dietary fiber-starch system.onset temperature.(2)By measuring the characteristics of starch gels stored at different times,the interaction between dietary fiber,ferulic acid,and starch during the retrogradation process was analyzed.SDF increased the water separation rate of RS gel,but IDF had no significant effect.FA reduced the water separation rate of the SDF-RS system gel and increased the water separation rate of the IDF-RS system gel.Both SDF and IDF reduced the gel strength and breaking strength of RS gel,and the reduction effect of SDF was extremely significant.FA enhanced the gel strength and burst strength of the dietary fiber-starch gel system.Both SDF and IDF reduced the chain length of amylose molecules and the molecular polymerization degree of amylopectin molecules in the RS gel.The influence of FA on the iodine binding properties of the dietary fiber-starch system was relatively complicated,but to a certain extent,the iodine blue value,iodine binding force,and maximum absorption wavelength showed an increasing trend.(3)The rheological test of the fresh gel of the system showed that all the systems were typical weak gel systems.Both SDF and IDF decreased the storage modulus(G?)and loss modulus(G??)of RS gel;SDF increased the loss tangent(tan?)of RS gel,and IDF decreased the tan?of RS gel.FA reduced the G?and G??of the SDF-RS system gel and increased the tan?of the gel system.FA increased the G?and G??of the IDF-RS system gel and weakened the tan?of the gel system.All systems were typical pseudoplastic fluids.SDF reduced the yield stress(?₀),consistency coefficient(k),and thixotropic ring area of the RS gel system and increased flow behavior index(n).IDF reduced the k,n,and thixotropic ring area of the RS gel system.FA increased the SDF-RS gel system and the area of the thixotropic ring and decreased n.FA increased the?₀,k,and thixotropic ring area of the IDF-RS gel system.The SDF-RS system and SDF-FA-RS system exhibited weak viscoelastic behavior.IDF increased the instantaneous modulus of elasticity(J_0c),delayed modulus of elasticity(J_1c),and delay time(?_1c)of the RS gel system and decreased the Newtonian viscosity(?₀).FA decreased the J_0c,J_1c,and?_1c of the IDF-RS gel system and increased?₀.(4)The dynamic rheology-frequency sweep measurement showed that the main force maintaining the dietary fiber-starch system was the hydrogen bond force.By analyzing the infrared spectrum,FA increased the density and strength of hydrogen bonds in the dietary fiber-starch system and caused some groups to undergo redshift.There was an electrostatic interaction between FA-RS.SDF,IDF,and FA reduced the order of starch structure in the system.By analyzing the transverse relaxation time,the addition of SDF and IDF increased the fluidity of the water molecules with the highest proportion in the RS gel system,and FA weakened this trend to a certain extent.