| In this paper,starch was used as the main research object,dry heat treatment combined enzymatic hydrolysis was used to prepared porous starch as a modified method,and the process was optimized.The effects of enzymatic hydrolysis,dry heat treatment,and dry heat treatment combined enzymatic hydrolysis on starch structure and physical and chemical properties were analyzed.Using porous starch as a carrier to absorb curcumin,combined with pectin/sodium alginate to prepare colon-specific drug delivery particles.The research mainly provides theoretical basis for further optimizing the preparation process of porous starch,improving the quality of porous starch and expanding its application field.The main research contents are list as follows:1.Corn starch was used as raw material,the process conditions for preparing porous starch by dry heat treatment combined enzymatic hydrolysis was optimized.Single factor test,Plackett-Burman and Box-Behnken Design response surface test were used to obtain the optimal conditions for preparing porous starch.The Plackett-Burman results showed that the factors that have a significant impact on the starch adsorption rate are reaction time,reaction temperature,enzyme dosage,pH and dry heat treatment temperature,and other factors are not significant.On this basis,a response surface test was carried out to determine the optimal preparation conditions for starch: reaction temperature 50?,reaction time 10 h,enzyme addition 3%,pH 5.0,dry heat treatment temperature 130?.2.The effects of enzymatic hydrolysis,dry heat treatment,and dry heat treatment combined enzymatic hydrolysis on the structure and physical and chemical properties of porous starch granules prepared by enzymatic hydrolysis were analyzed by using scanning electron microscopy(SEM),specific surface area analyzer,thermogravimetric analyzer(TGA),X-ray diffractometer(XRD)and other instruments.The adsorption capacity,crystal structure,thermal characteristics,specific surface area and porosity of starch were analyzed.The adsorption capacity of porous starch prepared by the combined treatment is greater than that of enzymatic starch.Dry heat treatment causes damage and pits on the starch surface.Compared with the porous starch prepared by single enzymatic hydrolysis,the starch prepared by dry heat treatment combined enzymatic hydrolysis has a larger number of pores on the surface,and the total pore volume and specific surface area are increased significantly.The results of XRD and FT-IR showed that dry heat treatment and enzymatic hydrolysis did not produce new groups in the starch,nor did it change the crystalline form of the starch,but the generation of holes destroys the structure of starch granules,and the porous starch prepared by dry heat assisted enzymatic hydrolysis has higher relative crystallinity than enzymatic starch.The RVA results show that after different modification treatments,the viscosity parameters of starch are all smaller than the original starch,and the viscosity parameters of starch forming pores are significantly reduced,and the viscosity of porous starch prepared by combined treatment is the smallest.It showed that dry heat treatment promotes the reaction of enzymes with starch and reduces its viscosity.3.The curcumin-porous starch/pectin/sodium alginate particles were prepared with pectin and sodium alginate as materials and porous starch as the carrier,and the release characteristics of the particles in the simulated intestinal fluid were studied.The adsorption capacity of curcumin by porous starch increases with the increase of curcumin concentration.When the curcumin content is 0.6%,the adsorption capacity reaches the maximum of 6.64mg/g.Curcumin-porous starch-pectin-sodium alginate particles have a low drug release rate in the gastric and small intestine simulation fluid,while in the colon simulation fluid,the drug releases suddenly,indicating that the particles have better colon-oriented release performance. |
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