【作者】 王海英；

【导师】 吴谋成；

【作者基本信息】 华中农业大学 ， 农产品贮藏与加工工程， 2001， 硕士

【摘要】 淀粉的资源丰富，已广泛应用于各个工业领域，随着工业生产技术的发展，原淀粉的性质已难以适用于很多领域，因此有必要对淀粉进行改性，使之能符合应用的要求。本文以植酸钠为改性剂，对淀粉进行酯化改性，通过红外光谱仪，X-射线衍射仪，扫描电镜，粘度计对植酸改性淀粉进行了反应机理和性质的研究，并对改性淀粉的应用基础进行了初步探讨。结论如下： 1．以两种方法进行改性，以取代度为指标，正交试验结果表明，在湿法改性中，得到最大取代度的反应参数为：植酸钠用量2％，pH7，淀粉乳浓度30％，时间9hr，温度50±5℃。在浸渍法改性中，得到最大取代度的反应参数为：植酸钠用量2％，pH 7，时间2hr，温度140℃～160℃。其中植酸钠用量和pH值是主要的影响因素。 2．对两种植酸改性淀粉的性质进行研究，认为所得改性淀粉为植酸交联淀粉，浸渍法改性淀粉的交联度低于湿法改性淀粉。改性淀粉的糊稳定性提高，凝成性弱，由于植酸对人体的安全性高，植酸改性淀粉很适于作食品中的增稠剂和稳定剂。 3．用植酸钠改性时，反应主要发生在淀粉颗粒的无定形区；改性淀粉颗粒的显微形貌保持不变，反应发生在颗粒的表面；推测支淀粉最先起反应，淀粉的C₆的伯醇羟基易于与植酸钠反应。 4．植酸改性淀粉可食性膜的最佳成膜条件是：甘油10％，山梨醇5％，羧甲基纤维素钠3％：植酸钠PVA淀粉膜最佳成膜条件是：PVA为20％，甘油5％，聚乙二醇400为10％，40℃～50℃干燥。 5．湿法植酸改性淀粉制得的膜的耐水性和阻湿性优于浸渍法植酸改性淀粉和原淀粉。大豆及菜籽蛋白质及其水解产物的添加使膜的溶胀性降低，柔韧性增加，蛋白水解液的添加对膜的柔韧性的改善更为明显，但强度都有所下降。菜籽蛋白的添加也使水蒸气透过率降低。蛋白种类的不同会影响膜的性质。更多还原

【Abstract】 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.更多还原