酸解氧化小麦淀粉的制备及性能

Preparation and Property of Acid-Thinned Oxidized Wheat Starch

以小麦淀粉为原料,盐酸为酸解剂,次氯酸钠为氧化剂,对酸解小麦淀粉的制备及性能进行了研究。考察了反应时间、反应温度、pH、次氯酸钠用量、酸解氧化顺序对酸解氧化小麦淀粉羧基含量的影响,采用糊滴定法测定羧基含量。比较了小麦淀粉、酸解小麦淀粉、氧化小麦淀粉及酸解氧化小麦淀粉性能。结果表明,制备酸解氧化小麦淀粉的较佳工艺条件为:反应温度40℃,反应时间2 h,pH 9.0,先酸解后氧化顺序优于先氧化后酸解顺序。小麦淀粉经酸解氧化后,其抗酸性、抗碱性、冻融稳定性均得到改善,蓝值增加,膨胀能力降低。小麦淀粉经酸解、氧化后,热稳定性变差;酸解提高了小麦淀粉的熔融焓,而氧化使其熔融焓降低。

The preparation and properties of acid - thinned wheat starch were studied by using wheat starch as raw materials, hydrochloric acid as acid - thinned agent, sodium hypochlorite as oxidant. The effect of some factors such as reaction time, reaction temperature, pH, amount of sodium hypochlorite and order of acidolysis oxidization on the carboxyl content of the acid - thinned oxidized wheat starch was investigated. The carboxyl content was determined by the hot paste titrimetric method. The properties of acid - thinned oxidized wheat starch were compared with those of wheat starch, acid - thinned wheat starch and oxidized wheat starch. The results showed that the better technology con- ditions for preparing the acid - thinned oxidized wheat starch were as follows ： reaction temperature 40 ℃, reaction time 2 h, pH 9.0 ; the order of first acid hydrolysis and then oxidization is better than that of first oxidization and then acid hydrolysis. After wheat starch was modified by acid or oxidized,its acid resistance, alkali resistance and freeze - thaw stability were all improved, with its blue value increased and its expansion ability decreased. After wheat starch was acid - thinned and oxidized, its thermal stability became poor. The acid hydrolysis increased the melting enthalpy of the wheat flour, but the oxidization decreased it.