Research On The Properties And Preliminary Application Of Self-Assembled Hybrid Hydrogel Based On Fmoc-F,Fmoc-Y/Food Colloids

Bioactive substances have the function of regulating the life activities of the body,and can improve human health and physical fitness.They are a class of biologically active compounds,including polysaccharides,peptides,sterols,terpenes,enzymes,plant essential oils,and so on.However,it has the disadvantages,such as unpleasant smell and poor stability,which inhibit the application of the bioactive substances.Among these bioactive substances,essential oils are volatile and the enzymes are inactivated easily.To solve these problems,materials such as liposomes,microcapsules,polypeptide hydrogels,and food colloids are used to embed biologically active substances.However,the polypeptide hydrogel has the poor stability and large pore size,and cannot protect the embedded material from environmental factors.The food colloids always have no pH response and cannot controlrelease the embedded materials.Therefore,in this paper,Fmoc-F,Fmoc-Y and 10 kinds of food colloids were used for preparing the hybrids hydrogels.The properties and structure of the hybrid colloids were studied,and the hybrid colloids which has the specific release characteristics were selected for preliminary application.The results and conclusions are as below:(1)Fmoc-F was hybridized with 10 kinds of food colloids to prepare Fmoc-F/food colloids self-assembled hybrid hydrogels.The rheological properties and release characteristics of 10 Fmoc-F/food colloids hybrid hydrogels were compared and analyzed.The results show that the rigidity of food colloids is enhanced after hybridization with FmocF,which is mainly because a tighter colloidal structure is formed between Fmoc-F and food colloids through intermolecular hydrogen bonds,which makes the pore size smaller.The secondary structure of hybrid hydrogel is β-sheet.Hybrid hydrogels(except Fmoc-F/gelatin and Fmoc-F/konjac gum)have the characteristics of slow release under acidic conditions and fast release under neutral alkaline conditions.Among the 10 kinds of hybrid gums,Fmoc-F/guar gum and Fmoc-F/sodium alginate have a wider linear viscoelastic range,can withstand greater stress,and have the better processability.The frequency dependence of Fmoc-F/guar gum is the weakest,and the colloid is the most stable;Fmoc-F/guar gum has a relatively uniform release rate in pH 4.5,7.4,and 10 environments,and is suitable as a slowrelease embedding material;Fmoc-F/sodium alginate in pH 1.7 environment,the release rate of the embedded material is less than 10%,and in pH 7.4 environment,the release rate reaches 100%in 6 hours,with good enteric release characteristics.(2)Fmoc-Y was hybridized with 10 kinds of food colloids to prepare Fmoc-Y/food colloids self-assembled hybrid hydrogels.The rheological properties and release characteristics of 10 Fmoc-Y/food colloids hybrid hydrogels were compared and analyzed.The results show that the rigidity of food colloids are enhanced after hybridization with Fmoc-Y,which is mainly because a tighter colloidal structure is formed between Fmoc-Y and food colloids through intermolecular hydrogen bonds,which makes the pore size smaller.The secondary structure of hybrid gum is mainly β-sheet.Hybrid gums(except FmocY/konjac gum)have the characteristics of slow release under acidic conditions and fast release under neutral alkaline conditions.Among the 10 kinds of hybrid gums,Fmoc-Y/guar gum and Fmoc-Y/sodium alginate have a wider linear viscoelastic range,can withstand greater stress,and have strong processability.The frequency dependence of Fmoc-Y/guar gum is relatively weak and the colloid is more stable;Fmoc-Y/guar gum has a relatively uniform release rate in pH 4.5,7.4,and 10 environments,and is suitable as a slow-release embedding material;Fmoc-Y/sodium alginate in pH 1.7 environment,the release rate of the embedded material is less than 10%,and in pH 7.4 environment,the release rate reaches 100%in 6 hours,with good enteric release characteristics.(3)The guar gum and sodium alginate were selected for hybridizing with Fmoc-F or Fmoc-Y.The rheological,morphological and release properties of the hybrid colloids were analyzed,and the preliminary application was carried out.The results show that FmocF/guar gum is suitable for encapsulating thyme essential oil for bacteriostasis.After 24 hours,the bacteriostatic effect of the embedded essential oil is 2.5 times than that of the unencapsulated essential oil.These results indicate that Fmoc-F/guar gum hybrid hydrogel could prevent essential oils from volatilizing and achieve slow-release effect and extend the bacteriostatic activity.Fmoc-Y/sodium alginate is suitable for encapsulating lactase for intestinal release.When the concentration of alginate was at 55%,the mass ratio of Fmoc-Y to sodium alginate was at 1/6,the enzyme activity retention rate after treated with simulated gastric juice was at 86.38%,which is much higher than that of sodium alginate(30.17%)and Fmoc-Y(12%)at the same concentration.