Preparation Of OSA-modified α-cyclodextrin And Its Application In Pickering Emulsion

Cyclodextrins are common and safe food ingredients and are widely used in food applications due to their low toxicity,good biocompatibility,environmental friendliness and their "hydrophilic outside,hydrophobic inside" structure.However,the application of cyclodextrins in food emulsion systems is limited by their cavity size,solubility and production composition,and a large number of modified cyclodextrin derivatives have emerged.In this thesis,α-cyclodextrin(α-CD)was selected as a raw material and hydrophobically modified using octenyl succinic anhydride(OSA)as an esterification reagent to prepare an ideal emulsifier particle model of α-cyclodextrin octenyl succinate(OS-α-CD)and to investigate its application in emulsion stabilisation and functional factor transport.The study provides a theoretical basis for the development and use of new emulsifiers and the application of emulsions as carriers for the delivery of functional factors.The main findings of this thesis are as follows:(1)OSA was used to modify the hydrophobicity of α-cyclodextrin to prepare OS-α-CD with amphiphilic properties.the successful esterification reaction between OSA andα-cyclodextrin,resulting in the change of morphology,was confirmed using FTIR,NMR,SEM,XRD,TGA and other detection techniques as the index of substitution degree(DS).The potential,particle size,contact angle and surface tension were also measured.After hydrophobic modification,the absolute value of OS-α-CD potential increased,the particle size decreased,and the contact angle and surface tension first increased and then decreased with increasing substitution degree.(2)Pickering emulsions were prepared using different degrees of substitution of OS-α-CD to investigate the stability and stabilization mechanism of the emulsions,and the results of Turbiscan stability analysis showed that the emulsions had good stability at DS0.017.Low-field NMR results revealed a more homogeneous oil-water distribution for a DS of 0.017.The rheological results demonstrate that all emulsions exhibit shear-thinning pseudoplastic fluid properties and that the stiffness of the interfacial film of the emulsion droplets is also governed by the degree of substitution.The results of the emulsion particle size potential at a DS of 0.017 show that the OS-α-CD particles have the strongest emulsification activity and that the emulsions are small and uniformly distributed.The emulsions had good physical and storage stability after 30 days of storage and laser confocal microscopy.The functional factor curcumin was delivered using different substitution OS-α-CD emulsions as carriers,and the effect of different delivery on the bioavailability of curcumin was initially investigated and compared by analysing the curcumin loading rate of the system and in vitro digestion simulations.The results showed that the OS-α-CD emulsion had a higher curcumin loading rate than the α-CD emulsion.In addition,the results of the different emulsion delivery systems after digestion and the release of free fatty acids showed that the DS of 0.017 OS-α-CD had higher oil digestion rate and 10.3% higher bioavailability due to the higher oil interfacial reactivity of the smaller emulsion particle size.