Properties And Application Of Gelatin/ Polysaccharide Hydrocolloids Co-gels

This paper studies the properties of gelatin/ carrageenan, gelatin/ carrageenan/ sodium alginate and gelatin/ carrageenan/ xanthan co-gels. By using dynamic thermo-mechanical analysis(DMA), rotating cylinder viscometer, texture analyzer, scanning electron microscopy(SEM), the viscosity, gelling temperature, thermodynamic properties, hardness and microstructure are analyzed and the effect of the factors such as metal ions, crosslinker, pH value, plasticizer on them are discussed.With the carrageenan concentration improved, the viscosity, gelling temperature, hardness, storage modulus and loss modulus of the first co-gel increased. The addition of KCl can reduce the viscosity and improve other properties. And with the pH value increased, the hardness rised because it changes the charged gelatin, affects the interaction between two gels.As the sodium alginate concentration of the second co-gel improved, the viscosity increased unceasingly, the hardness decreased after rising. Compared the two crosslinkers, CaCl₂ and ZnCl₂, the interaction between Ca²⁺ and sodium alginate is stronger and the hardness is larger, but with Zn²⁺, the junction is much more and the cavity is bigger. Glycerin(plasticizer) can reduce co-gel hardness effectively.With the improvement of xanthan concentration in the third glue, the viscosity and gelling temperature rised, the hardness decreased after rising. Research indicated that with the concentration of K+ and Ca²⁺ increased if added a certain content of KCl and CaCl₂, the viscosity declined, gelling temperature increased and hardness declined after rising. Contrasted to CaCl₂, the influence of KCl is stronger and the extent of performance change is larger.Meanwhile, this article took hydrophilic gel as shell material, prepared soft capsule wrapping the lipophilic core by dropping method. Research showed that due to gel performance brittleness, carrageenan wasn't used as shell material alone. But through adding gelatin and glycerin, gel brittleness can be effectively improved, the appearance, crush strength and deformation rate of soft capsule are improved. But if the gelatin concentration is bigger, it may be deformation and fracture. By study, the drying period can be shorten by improving drying temperature and depressing Relative humidity, but high temperature is easy to cause the capsule adhesion, deformation and surface folds. Cascade drying can resolve above problems and shorten the drying period, reduce energy consumption.