Department of Industrial and Physical Pharmacy, 575 Stadium Mall Drive, Purdue University West Lafayette, IN 47907, USA.
J Agric Food Chem. 2010 Nov 24;58(22):11716-24. doi: 10.1021/jf101941e. Epub 2010 Oct 21.
Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.
先前的研究表明，在高于其露点相对湿度 (RH) 的环境条件下储存时，易潮解的有机化合物经常表现出化学不稳定性。本研究的目的是研究在相互露点 RH (MDRH) 及以下的 RH 下储存后，大气湿度对结晶蔗糖-柠檬酸混合物的长期化学稳定性的影响。有趣的是，发现蔗糖水解可以在低于 64%的 MDRH 下发生，并且在 54% RH 下储存的样品中观察到了水解现象。但是，在 33%或 43% RH 下储存的样品中未观察到水解现象。通过考虑水分吸收的速率和程度，可以对蔗糖水解的速率进行建模，而水分吸收的速率和程度又取决于粉末的组成和储存 RH。提出了一种反应机制，该机制由毛细凝结引发，并涉及由于蔗糖水解（葡萄糖和果糖）形成的降解产物导致的进一步的露点降低。
