Construction And Application Of Wheat Bran Arabinoxylan-based Hydrogel System

Compared to single-network hydrogels,double-network hydrogels formed by polysaccharides and proteins tend to have stronger hydrodynamic and mechanical properties,and are more nutritionally comprehensive,and thus are commonly used as controlled release matrices for active substances in the food field.In this paper,wheat bran arabinoxylan（WBAX）and pea isolate protein（PPI）were used as raw materials to construct polysaccharide single-network and polysaccharide-protein double-network hydrogel systems,and the mechanism of arabinoxylan-based hydrogel formation was investigated from the physicochemical properties and microstructure of the gels.The main contents are as follows.The effects of different arabinoxylans（AX262,AX44,AX229）on the physicochemical properties,rheological properties and microstructure of arabinoxylan hydrogels（HG）were investigated by HPLC,GCMS,FTIR,rheometer,DSC,WHC,LF-NMR and SEM.The results showed that AX262 with high ferulic acid content（0.23μg/mg）and high molecular weight（1.17×10⁶Da）had strong oxidative cross-linking ability;during gelation,the consumption of ferulic acid was 96%,87%and 69%for AX262,AX44and AX229,respectively,with AX262 having a higher degree of oxidative cross-linking.The final storage modulus（G′）of AX262 solution（7%,w/v）was 1480.4 Pa,which was more elastic.SEM images showed that HG262 has a honeycomb network with a regular dense mesh structure,which was consistent with the result that the q,Mc andξvalues of HG262 were significantly（p<0.05）lower than those of HG44.A double network hydrogel system of WBAX（AX262）and PPI was constructed and investigated by rheometry,DSC,WHC,LF-NMR,SEM and CLSM.The results showed that the double network structure could be designed by adjusting the concentrations of WBAX and PPI;the rheological results confirmed that the double network gels were formed by a two-step sequential gelation method of laccase catalyzed cross-linking and heating;increasing the concentrations of WBAX and PPI,respectively,increased the G′of the double network gels from 385.1 Pa to 2623.2 Pa and 7133.4 Pa.SEM and CLSM observed that the double network gels exhibited interconnected bicontinuous structures,and the increase in WBAX concentration contributed to the formation of more homogeneous and smaller pore size gel structures.LF-NMR showed a significant decrease in T₂₂with increasing WBAX concentration（p<0.05）,indicating a decrease in the mobility of water molecules within the double network gels.FT-IR,fluorescence spectroscopy analysis and SDS-PAGE results indicated that the cross-linking of WBAX-WBAX,PPI-PPI and WBAX-PPI was involved in the formation of WBAX-PPI double network gels.The WBAX-PPI cold-set double network gel system was constructed using laccase and transglutaminase,and its in vitro digestion properties were investigated.The results showed that the WBAX-PPI cold-set double network gel has the potential as a carrier for colon-targeted drug delivery.The CLSM results showed that the covalent networks of WBAX and PPI were interconnected and showed a bicontinuous structure;the LF-NMR results showed that the T₂₂of the gel decreased significantly（p<0.05）with the increase of WBAX concentration and converted into water molecules with low mobility,which was related to the gradual dominance of macroporous structure in SEM.The rheometer results showed that the tanδof the gel increased from 0.1 to 0.5 with the increase of WBAX,indicating the decrease of gel strength,while WBAX mainly enhanced the gel viscosity;in vitro digestion experiments,the encapsulation efficiency of double network hydrogel samples with low WBAX concentration（≤3%,w/v）with regular structure was significantly higher（p<0.05）than other samples,gastric digestion The release rate after gastric digestion was low and the release rate after intestinal digestion was high,which has the potential to be used as a carrier for colon-targeted drug delivery.