Study On The Function Of Konjac Glucomannan/gum Karaya Delivery System

Konjac glucomannan(KGM)is a widely renewable natural polysaccharide with excellent properties of swelling,rheological and biocompatibility.After entering the digestive system of human body,it will not be degraded by protease which present in the stomach and small intestine.KGM can be used to establish a hydrogel delivery system loaded with bioactive substances.However,the gels formed by the unmodified KGM are easily swells and disintegrated in water,and they are difficult to form a gel with good texture characteristics.Gum karaya(GK)is a partially acetylated weakly acidic polysaccharide with good biocompatibility and biodegradability.Uronic acid presented in GK enables it to maintain a stable structure in the stomach acid environment.This research aims to fully utilize the biocompatibility of KGM and GK to build a stable structure of KGM/GK hydrogel delivery system through the interaction between them.In order to enhance the bioavailability of riboflavin,we further study the controlled release effect of gel system to riboflavin.Thereby,this work also provides a theoretical basis for further research on KGM relating hydrogel apply to protection,stability and release of bioactive substances to human target organs.The main research contents and results of this article are as follows:(1)Study on the texture characteristics of konjac glucomannan/gum karaya gel systemIt was found that the reconstitution of KGM and GK under certain conditions could exhibit a strong synergistic effect and form a stable gel system.Therefore,this study used a single factor test method to examine the effect of various factors on the gel strength of KGM/GK.On the basis of single-factor tests,I investigated the gel strength of KGM/GK gel system based on parameters of bath temperature,substrate ratio,and stirring time.Response surface optimization design method of three factors and three levels was used to analysis the gel properties effect of KGM with GK.The optimum preparation conditions were obtained after calibration,when bath temperature,substrate ratio(KGM:GK)and stirring time at 50℃,2:8 and 60 min,respectively.Model prediction that maximum KGM/GK gel strength is 2574.98 g·mm.(2)Study on the rheological properties of KGM/GK gel systemThe rheological analysis of the steady-state shear flow behavior showed that the KGM/GK sol system exhibits "shear-thinning" behavior,which was a typical non-Newtonian fluid property,indicating that the KGM/GK sol system was a pseudoplastic fluid.The viscosity of the KGM/GK sol gradually increased with the increase of the addition of GK,and reached a maximum of 32 pa·s at a ratio(KGM:GK)of 2:8.The rheological analysis of shear rate and shear stress demonstrated that the addition of GK increased the shear stress of the KGM/GK hydrogel significantly.When the ratio(KGM:GK)was 2:8,the shear stress reached a maximum value.The elasticity was the main structural characteristic of the KGM/GK hydrogel obtained by sweeping the strain and frequency.The elasticity of the KGM/GK gel system was better at a ratio(KGM:GK)of 2:8.The temperature scanning showed that KGM/GK transform into sol state from gel state when the environment temperature was higher than 45℃,and the viscosity of KGM/GK gel system appear linear downward trend with the rising of the temperature.(3)Analysis of structural characterization of KGM/GK gel systemInfrared spectral scanning and X-ray diffraction scanning results showed that the addition of GK promoted the curling and entanglements between KGM and GK molecules,which contributes to the formation of intermolecular hydrogen bonds.At the same time,the carboxyl group in the GK molecule could act as a binding site for ionic bonds,thereby affecting the gelling properties and viscosity of the system.The results of TGA and DSC scanning showed that the addition of GK improved the thermal stability of the system.The microstructure analysis of the KGM/GK gel system by scanning electron microscopy(SEM)showed that the inside of the gel was a typical cellular honeycomb structure with a small pore size and a large number of specific surface areas,which was conducive to the protection/release of biologically active substances.The interior of the gel pores loaded with riboflavin was filled with particles,demonstrating the efficient loading of riboflavin by KGM/GK gels.(4)Study on the mechanism of controlled release riboflavin of KGM/GK gelThe riboflavin was loaded on the KGM/GK gel under optimal preparation conditions,and the porous KGM/GK-RF carrier-loaded gel was obtained by vacuum freeze-drying technique.Then the vitro release of riboflavin was simulated.The results showed that KGM/GK gel can effectively protect riboflavin,promote it stable and targeted achieved maximum release in the small intestine,then improve bioavailability.This experiment demonstrated that the KGM/GK gel system can be used to develop functionalized gel delivery vehicles for the delivery of functional components such as nutrients and health-care molecules in the intestine.Furthermore,this experiment could provide theoretical basis and guidance for related research.