Preparation And Property Of Modified Corn Starch

In recent years, Starch, as an important natural polysaccharide, has been widely used in food, papermaking, textile, architecture, medicine and so on. However, the physical and chemical drawbacks limited industrial application of natural starch. In this paper, we modified waxy corn starch and investigated its application in light industry.Firstly, the crosslinked starch microspheres encapsulating lavender oil(CSM-LO) were prepared through interfacial polymerization and double emulsion using waxy com starch and lavender oil as wall and core material.The effects of crosslink agent content, emulsifier content, the volume ratio of inner emulsion/oil phase (Vinner emulsion:Voil) and essential oil mass fraction on the morphology of CSM-LO were investigated. Fourier transform infrared spectroscopy (FTIR) and Thermal gravimetric analysis (TGA) were used to characterize its structure and thermal stability. TGA and ultraviolet spectroscopy studied the slow-release of LO from CSM.The morphology of CSM-LO was spherical at the optimum synthesis condition, that was: crosslink agent content 30%, emulsifier content 5%, Vinner emulsion:Voil 1:14 and wt(lavender oil) 50%. The results showed the successful encapsulation of LO, the increased thermal stability.TGA and ultraviolet spectroscopy results showed that LO in CSM-LO was slowly released with time and the release profile of LO from the CSM could be well described by First-order kinetics equation, that is ln(1-Mt/M∞)=-0.3783t-0.7582.Secondly, a new cross-linked starch with porous structure (CPS) was synthesized by reverse emulsion polymerization, using waxy corn starch after enzyme hydrolysis (ES) as raw material and N,N’-methylene-bis-acrylamide as cross-linking agent. The effects of the volume ratio of oil phase/aqueous phase (Voil:VH2O), the content of emulsifiers, ES and MBAA on the properties of CPS were investigated.The structure and morphology of CPS have been characterized by FTIR, TGA, Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The optimum CPS was used in leather retannage process and the characterization of physical test, SEM, FTIR, X-ray photoelectron spectroscopy (XPS), TGA and DSC was used to study the interaction between CPS and collagen molecules.The propery reached to the top at the optimum synthesis conditions, that was:Voil:VH2O 8:1, emulsifier content 9%, starch content 2% and MBAA content 10%. The results showed that the cross-linking reaction between ES and MBAA, the sponge-like structure of CPS, the increased thermal decomposition temperature to 250℃ and the decreased gelatinization temperature and enthalpy value. Physical test, SEM, FTIR, XPS, TGA and DSC showed that CPS attached on the surface of collagen fibrils and interacted with collagen molecules without change its triple helical structure. Oxygen content of retanned collagen rised, Cr(OH)3 formed coordination bond with hydroxyl or carboxyl groups, hydrogen bond with hydroxyl groups and shiff base occurred between CPS and polypeptide chains during retannage process.These interactions improved the thickness increment ratio, tear strength, grain distension, decreased thermal stability and change the structure uniformity of retanned leather.