Study On The Structure, Rheology And Release Of Konjac Glucomannan/Gellan Gum Blend Materials

Gellan gum (GG) has widely applications in the hydrophile gel materials for its special properties of gelatin and good control release. But it also has some disadvantages such as difficult to process, high costs, low release rates, and so on. Konjac glucomannan (KGM) was a rich resource in China. This article was aimed to produce the KGM/GG blend materials, study on the structure of blend films, processing rheological properties of sol and gels, and preliminary evaluate the drug release properties of mix gel spheres, by using modern macromole research methods. It provided the experimental datas and theory for the natural foods colloidal drug composite materials research and application.Main research contents and results:1 The characteristic and structure of blend films were studied by Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differential scanning calorimetry. The physical property testing showed that the tensile strength increased with the content of KGM, and reached the maximum peak value when KGM% was 70% (KG7). The breaking elongation didn't have conspicuous change. The FT-IR spectra showed that no matter what the rate of KGM to GG. absorb peaks didn't have distinct change except O-H stretch vibration. It noted that the intermolecular between KGM and GG was mainly physical interaction. The scanning electron micrographs showed that the smooth and homogeneous cross-section morphology of KG7. With the increase of KGM, the crystallinities of the blend films didn't appear, so it meant that diffraction peaks were syncretized separately. With the two blending, the exothermic peak temperatures of GG were rising constantly, and the pyrolysis peak of KGM continuously dropped, similarly shows that the two have a weak compatibility.2 Pure and blend sols both showed the characteristics of non-Newtonian fluid, and rheological curves accorded with the power law t = KDⁿ. The temperature influence is great on the viscosity of blend sols. The best compatibility (KG7) showed the largest pseudoplastic. With the increasing of GG, G'(storage modulus) increased, which meant that GG played a great role in the flexibility of the gels. The rates of KGM/GG which were more than 5:5 showed the fluid characteristics, and the less ones demonstrated solid features. The gels texture profiles ware significantly affected by the metal cations. In a certain concentration range, the increase of cation can promote the gel's hardness and cohesiveness. But when further enhance the cations concentration, the gel will be damaged homogeneity.3 L-carnitine KGM/GG composite hydrogel spheres were prepared by using dripping method. The best molding conditions: the concentration of CaCl₂ was 0.1 mol/L; drops rate was 60 drops/min; the drop height was 5cm. Analysis the texture of composite gel spheres. The results showed that the hardness and cohesiveness of the spheres were positively correlated with GG. Observed the wet and dry gel spheres shapes. The results showed that the wet gel sphere surface was smooth while the dry gel sphere surface was drape. Preliminary testing the composite hydrogel spheres release in vitro. The results showed that release curves accorded with Weibull equation. The release behavior of composite gel spheres was seemed as a hydrophilic gel matrix function, however, it needed further studying.