用 H 核磁共振法测定改性淀粉中羟丙基含量的改良方法。
An improved method to determine the hydroxypropyl content in modified starches by H NMR.
机构信息
Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA.
出版信息
Food Chem. 2019 Oct 15;295:556-562. doi: 10.1016/j.foodchem.2019.05.152. Epub 2019 May 23.
Hydroxypropyl (HP) starches are used as thickeners and stabilizers in foods. The properties of the etherified starches are dependent on the degree of hydroxypropylation. The objective of this study was to develop an improved acid hydrolysis method to degrade and solubilize HP starches for determining HP content in modified starches by H NMR. The effects of acid (DCl) concentration and temperature on hydrolysis and solubilization of hydroxypropylated starches were examined. The optimal conditions proposed to hydrolyze HP starches were 10% starch solid content, 3.5% (wt%) DCl in DO as the solvent, sodium acetate as an internal standard, and heating at 90 °C for 1 h. Optionally, 6% (v/v) TFA-d may be added as the water-peak shifting reagent. Six hydroxypropylated starches and two cross-linked and hydroxypropylated starches were hydrolyzed with this improved acid method, and the results of the HP content were in agreement with those from an enzyme-catalyzed method.
羟丙基（HP）淀粉被用作食品中的增稠剂和稳定剂。醚化淀粉的性质取决于羟丙基化的程度。本研究的目的是开发一种改进的酸水解方法，以降解和溶解 HP 淀粉，通过 1H NMR 测定改性淀粉中的 HP 含量。考察了酸（DCl）浓度和温度对羟丙基化淀粉水解和溶解的影响。提出的水解 HP 淀粉的最佳条件为淀粉固含量 10%，溶剂为 3.5%（wt%）DCl 在 DO 中，醋酸钠作为内标，在 90°C 下加热 1 小时。可选地，可以添加 6%（v/v）TFA-d 作为水峰移位试剂。用这种改进的酸法水解了 6 种羟丙基淀粉和 2 种交联羟丙基淀粉，HP 含量的结果与酶催化法的结果一致。
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