Christina Belinda, Taylor Lynne S, Mauer Lisa J
Purdue University, Department of Food Science, 745 Agriculture Mall Drive, West Lafayette, IN 47907, USA.
Purdue University, Department of Industrial and Physical Pharmacy, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA.
Food Res Int. 2015 Oct;76(Pt 3):867-877. doi: 10.1016/j.foodres.2015.08.009. Epub 2015 Aug 13.
The effects of different polymer types on inhibiting the crystallization of ascorbic acid (VitC) from amorphous solid dispersions at various temperatures and relative humidities (RHs) were studied. Polymer properties (ability to form hydrogen bonds with VitC, hygroscopicity, and glass transition temperature (T)) were correlated to their crystallization inhibitor performance. Solid dispersions of VitC with different pectins, polyvinylpyrrolidone (PVP), and polyacrylic acid (PAA) were formed from lyophilized solutions. Crystallinity, VitC-polymer interactions, hygroscopicity, and T were determined using X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), moisture sorption isotherm, and differential scanning calorimetry (DSC) methods, respectively. XRPD amorphous VitC could not be formed by lyophilization in the absence of a polymer, nor in PAA dispersions, but could be formed in pectin and PVP dispersions. The VitC-pectin and PVP dispersions remained amorphous when stored at low RHs, but some crystallization occurred within one week at high RHs. Evidence of hydrogen bonding between VitC and both pectins and PVP, but not PAA, was found in FTIR spectra, and correlated better with physical stability than the T. The hygroscopicity of the polymer also influenced the stability of the amorphous VitC solid dispersions. A ranking of the polymer crystallization inhibitor properties was: PVP>pectin with lower degree of esterification (DE)>pectin with higher DE >>PAA.
研究了不同类型聚合物在不同温度和相对湿度（RH）下对抑制抗坏血酸（维生素C）从无定形固体分散体中结晶的影响。将聚合物性质（与维生素C形成氢键的能力、吸湿性和玻璃化转变温度（T））与其结晶抑制性能相关联。通过冻干溶液形成了维生素C与不同果胶、聚乙烯吡咯烷酮（PVP）和聚丙烯酸（PAA）的固体分散体。分别使用X射线粉末衍射（XRPD）、傅里叶变换红外光谱（FTIR）、水分吸附等温线和差示扫描量热法（DSC）测定了结晶度、维生素C-聚合物相互作用、吸湿性和T。在没有聚合物的情况下，通过冻干无法形成XRPD无定形维生素C，在PAA分散体中也无法形成，但在果胶和PVP分散体中可以形成。维生素C-果胶和PVP分散体在低RH下储存时保持无定形，但在高RH下一周内会发生一些结晶。在FTIR光谱中发现了维生素C与果胶和PVP之间存在氢键的证据，但与PAA之间没有，并且与物理稳定性的相关性比T更好。聚合物的吸湿性也影响了无定形维生素C固体分散体的稳定性。聚合物结晶抑制性能的排序为：PVP>低酯化度（DE）的果胶>高DE的果胶>>PAA。
