Studies On Preparation Of Phytic Acid Modified Starch And Its Application Basis

Starch is one of the most abundant substances in nature, which has been widely used in many industry fields. With the development of industrial technology, native starch cannot meet the requirements of certain uses; so it is necessary to develop modified starch. By means of infrared absorption spectroscopy, X-ray diffraction, scanning electron microscope and viscometer, the properties and uses of phytic acid modified starch were discussed. The results show:1. Result of orthogonal test indicated that reaction parameter of the highest degree of substitute (DS) to wet method PA modified starch was: sodium phytate 2%, starch emulsion concentration 30%, pH7, 50卤5 , 9hour; that reaction parameter of the highest DS to dipping method PA modified starch was: sodium phytate 2%, pH7, 140 ~160 , 2hour.2. Studying on two kinds of modified starch. It was found that PA modified starch might be esterifying cross-linked starch, and that cross-linking degree of dipping method PA modified starch was lower than wet method PA modified starch. Stability of the paste of modified starch was improved. Because phytic acid was safe to human body, phytic acid modified starch could be used as food thicking agent and food stable agent.3. Maize starch was modified with sodium phytate, whose morphology was same as those of native starch granules, and the reaction took place in the amorphous size of starch granules. It was supposed that sodium phytate first reacted with amylopectin and hydroxyl groups of primary alcohol of C6 in starch molecular.4.The optimized preparing condition of edible modified starch membranes was: glycerol 10%, sorbitol 5%, CMC-Na 3%, drying at 40~50 . And the optimized preparing condition of PVA modified starch membranes was: PVA 20%, glycerol 5%, polyethylene glycol 400 10%, drying at 40~50 .5. Water tolerance and moisture resistance of wet method PA modified starch were higher than those of native and dipping method PA modified starch. Swellability of the membrane decreased with the adding of soybean protein, rapeseed protein and their hydrolysates; its flexibility increased too. The increasing of flexibility was more obvious when protein hydrolysates added, but tensile strength of membrane decreased in a degree. Adding of rapeseed protein made water vapor transmission reduced. Species of protein would affect properties of membranes.