Preparation Of Soybean Protein Transparent Hdydrogels And Its Control-release Properties

The hydrogel is a kind of gel formed by covalent bond, hydrogen bond or van der Waalsforces. Hydrogels constitute a three-dimensional network structure, and maintain largeamounts of water without dissolving during swelling process. In this paper, heating processand protein/polysaccharide interactions, enzymatic cross-linking method were applied toimprove the structure of gel formation in order to prepare hydrogels with good swellingproperties. Besides controlled release properties was studied.1)4%(w/v) soy protein isolate solution was maintain at pH=2.0±0.01, and was set ata constant shear stress, ie, stirring speed rate of300rpm at80℃for10h. The acidic proteinthermal aggregates were prepared for making hydrogels. The results showed that: the proteingel had higher mechanical strength and transparent appearance, and the gelation time wasshorten, and had better tolerance of higher NaCl level.2) In this study, soybean11S glycinin and dextran sulfate (DS) were put together in theheating conditions to form heat aggregates and MTGase cross-linking method was applied toprepare cold-set hydrogel. The microstructure, rheology properties, texture properties,swelling behavior as well as the controlled-release nature were investigated in the study. Theresults show that: DS/11S ratio and ionic strength can affect the water holding capacity,rheological characteristics and textural properties of hydrogels; scanning electron microscopeshow that the addition of DS could help to form a stable network structure and increase waterholding capacity of hydrogel.3) The swelling behavior of MTGase cross-linking11S/DS glycinin cold-set transparentgel was studied. Besides types of interaction force of hydrogel, the state of water anddiffusion type of hydrogels in pH=1.2and pH=7.5was disccused. In addition, this studyexamined the loading and encapsulation properties, and the micro-structure of MTGasecross-linking11S/DS glycinin cold-set transparent gel.4) This study examined the release process under the condition of the gastrointestinalenvironment. The results showed that: charge in gel network was a major factor on affectingthe gel tendency to release and its release rate; besides digestive properties of enzymes can also affect in control-release process. Added DS/11S=0.100, maintained the drug-loaded gelin simulated gastric fluid (including enzymes) to release for1h, the release rate was only10.98%, moved it to the simulated intestinal fluid (including enzymes), the release rate in thesubsequent5h with the release of89.95%. The MTGase11S/DS transparent cold-set gelloading and controlled release effect was good on control-release performance of riboflavin.