| Octenyl succinic starch (OSS) is one kind of modified starches widely used in food, pHarmaceutical, paper, textile and cosmetics industries, et al. This paper mainly studied on the methods of preparing octenyl succinic cassava starch (OSCS). Radius basis function neural network and genetic algorithm (RBFNN-GA) was applied to forecast the most suitable conditions. The pHysicochemical properties and its application were also investigated. Details were as follows:Firstly, ordinary wet process and dry one ffected on the degree of substitution (DS) and reaction efficiency (RE) of OSCS were studied. It indicated that the former was the better one. Then we put forward the sub-gelatinized wet preparation method and studied its process conditions.Secondly, RBFNN-GA was applied to forecast the most suitable conditions. The optimal combinations were as follows:sub-gelatinized temperature74.0℃, starch concentration27.4%(in proportion to aqueous solution of ethanol, w/w); the volume fraction of ethanol47.0%; sub-gelatinized time169.2min; esterified pH7.64; temperature28.9℃, time102.4min and octenyl succinic anhydride (OSA) concentration3%. Under these conditions, the DS was0.0178and the RE was76.8%.Thirdly, differential scanning calorimetry, fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy were used to analyze the structure of cassava starch. It indicated that the crystalline structure of starch granules was destroyed and some pores and cracks were formed on the surface. These changes increased the opportunity to react with OSA. The starch ester existed in the form of octenyl succinate sodium.Finally, the pHysicochemical properties of starch paste and application in yogurt were discussed. The solubility, viscosity, clarity, antiflocculation and freeze-thaw stabilities were improved after modification. It can be used as a thickener in yogurt. |
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