Preparation And Properties Of Hydroxycinnamic Acid Mesoporous Starch Ester

Compared with native starch(NS),mesoporous starch(MS)has the advantages of high specific surface area and release of more chemical reaction sites,making mesoporous starch a research hotspot.However,most of the current research is devoted to the preparation of mesoporous starch,and there is little research on the chemical modification of mesoporous starch,and there is no report on the esterification of functional hydroxycinnamic acid(HA)to mesoporous starch.Therefore,in this paper,mesoporous starch as the main of reaction and hydroxycinnamic acid as the guest,the preparation and properties of hydroxycinnamic acid mesoporous starch ester(HA-MS)were studied.Mesoporous starch(MS)was prepared using potato starch as a raw material by freezing solvent exchange method.Native potato starch granule is mostly oval or ellipsoidal,with smooth and complete surfaces.Mesoporous starch(MS)has a small pore structure,uneven pore distribution,and rough surface.The MS has a specific surface area of 14.39 m2g-1 and an average pore size of 226.61A(22.66 nm),which is in line with the definition of mesoporous starch.Compared with the B-type crystals of potato starch,MS has no obvious diffraction peak.Hydroxycinnamic acid(HA),including cinnamic acid(CA),ferulic acid(FA),p-coumaric acid(p-CA)and sinapic acid(SA),were esterified with MS to prepare a series of hydroxycinnamic acid mesoporous starch esters(HA-MS)donated as CA-MS,FA-MS,p-CA-MS and SA-MS.Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(NMR)were used to characterize the four types of HA-MS.It was proved that HA was connected to MS in the form of the ester bond.The structure of HA-MS was characterized by scanning electron microscopy(SEM),N2-adsorption and X-ray diffraction.Physicochemical properties and structure were explored by studying a series of physicochemical properties of HA-MS,such as ultraviolet absorption performance,light stability,thermal stability,emulsification performance,and rheological property.The UV absorption spectra showed that the MS did not have UV absorption performance,but the HA-MS had strong UV absorption.HA-MS showed the better light stability.The results of thermogravimetric analysis showed that the decomposition temperature and maximum pyrolysis temperature of each HA-MS were higher than that of MS,and the thermal stability increased with the degree of substitution of each HA-MS.The emulsion was prepared by HA-MS have stronger stability than that of MS,indicating the improvement of emulsification performance on HA-MS.The research of rheological properties shows that weak gel property was exhibited by the HA-MS solution and the viscosity was positively correlated with the degree of substitution and the concentration of HA-MS.Five chemical methods including scavenging hydroxyl radicals,scavenging DPPH radicals,chelation of Fe2-metal ions,reducing power,and ?-carotene-linoleic acid lipid peroxide were comprehensively evaluated for antioxidant activity of HA-MS.The results showed that the MS had no antioxidant activity,the antioxidant activity of CA-MS was low,and there was no dose-effect relationship.Oxidation activity increased with the degree of substitution and concentration of HA-MS,except for CA-MS.The order of HA-MS antioxidant activity is:SA-MS>FA-MS>p-CA-MS>CA-MS.