乙酰化羟丙基淀粉改性次序及程度研究

Determination of Modified Sequence and Degree of Acetylated and Hydroxypropylated Starch

为确定复合改性对淀粉性质的影响,从而为复合改性淀粉在食品中的应用提供参考。以玉米淀粉为原料,在羟丙基淀粉及乙酰化淀粉2种单一改性淀粉研究的基础上,采用分光光度法确定单一改性淀粉取代度,并以复合取代度为指标,探讨乙酰化羟丙基复合改性淀粉的改性次序及改性程度对复合改性淀粉制备的影响。结果表明:水解作用与空间位阻是影响复合改性效果的重要因素;乙酰化羟丙基复合改性淀粉合理的改性次序应为先羟丙基化后乙酰化,且在一定范围内,乙酰化反应不受羟丙基化程度的影响。

In order to figure out the effect of dual - modification on properties of starch, a scientific evaluation method, which could be used as a reference for the application of dual - modified starch in food industry, was estab- lished in the paper. With the corn starch as raw material, a spectrophotometric method to determine the single degree of substitution （DS） of modified starch was applied. Based on the study of hydroxypropylated starch and acetylated starch, using total DS as an indicator, the effect of sequence and degree of acetylation and hydroxypropylation dual - modification on starch preparation was studied in this paper. The results showed that hydrolysis and steric hindrance were the main factors of dual - modification. The sequence of acetylated and hydroxypropylated dual - modification should be hydroxypropylation first, then acetylation. The degree of hydroxypropylation did not affect the acetylation in a certain range.