Studies On The Preparation Technology And Properties Of Waxy Corn Crosslinking And Esterfying Starch

Waxy corn is a special type of corn (subspecies), originated in China. China's waxy corn rich in natural resources It is widely distributed in our coun -try, and many provinces have planted.At present, China's most waxy corn is used for fresh or processed food simple,so it has low added value.In order to raise the useness value and economic benefits of waxy corn, we need make a multi-level waxy corn deep-processing. Therefore,it has great significance to accelerate waxy corn processing research and enhance the useness value of waxy corn.In this study, using waxy corn starch as raw materials, phosphorus oxychloride for cross-linker , sodium tripolyphosphate and acetic anhydride for esterification agents respectively ,which perpared phosphated distarch phosphate and acetylated distarch phosphate by cross-linking and esterifying double-modified. Then the granules properties and paste properties of cross -linking and esterifying starch were studied. The main results were as follows:1. The preparation conditions of cross-linking and esterifying starch. At first, the factors which affect cold viscosity of cross-linking and esterifying starch paste were studied by single factor experiment.We make sure the orthogonal experiment factors based on the single factorial experiment.We carry through the orthogonal experiment by starch paste cold viscosity as evaluate target .The optimum technique parameters: The preparation conditions of phosphated distarch phosphate is: phosphorus oxychloride ratio is 0.025%, pH value is 11.5, reaction time is 50 minute,the degree of substitution of phosphated starch is 0.03;The preparation conditions of acetylated distarch phosphate is:crosslinking pH value is 10.8, crosslinking time is 20 minute, phosphorus oxychloride ratio is 0.015%, esterifying pH value is 9.1, esterifying time is 70 minute.2. Properties of cross-linking and esterifying starch. Properties of granules and paste of native starch and cross-linking and esterifying starch were compared, the conclusions were as follows:When the starch were modified by cross-linking and esterifying ,The surface of starch granules become crassitude. At same time starch granules swelled, caves , cracks and adheres appeared on the surface of granules.And the appearance of granules were changed. It showed that cross-linking and esterifying occurred not only on the surface of granules,but also the interior. Cross-linking and esterifying occurred not only in the amorphous regions,but also in the crystal regions by the analysis of X-ray diffraction of starch.Cross-linking and esterifying starch decreased pasting temperature of native starch.Compared with native starch, the paste peak viscosity,Trough viscosity and final viscosity of cross-linking and esterifying starch increased markedly .And the paste viscosity stability increased. The starch paste had better stability against acid and alkali, high temperature and shearing after cross-linking and esterifying . Cross-linking and esterifying starch had higher clarity compared with crosslinking starch.The results showed that cross -linking and esterifyin starch possessed good qualities of crosslinking starch and acetateester starch.It will accommodate to the developmeng of food industry.