Kodali D R, Atkinson D, Redgrave T G, Small D M
J Lipid Res. 1987 Apr;28(4):403-13.
The polymorphic behavior of symmetric diacid triacylglycerols (TGs), 1,3-dioleoyl-2-stearoyl (OSO), 2-elaidoyl (OEO), and 2-vaccinoyl (OVO) glycerols were studied by differential scanning colorimetry (DSC) and X-ray diffraction and compared with the corresponding monoacid TGs triolein (OOO), tristearin (SSS), trielaidin (EEE), and trivaccinin (VVV). The monoacid TGs formed a bilayered structure in all the polymorphic forms. On quenching from the melt, the diacid TGs OEO and OVO formed a bilayered (D = 45 A) beta'-phase with the exception of OSO, which formed a hexagonally packed bilayered (D = 52 A) alpha-phase. At -7 degrees C, the alpha-phase of OSO quickly transformed to a bilayered (D = 45 A) beta'-phase. Incubation at the beta'-phase melting temperature transformed OVO, OEO, and OSO into a trilayered (D = 65 A) beta-phase, where the 1,3-dioleoyl chains are segregated from the vaccinoyl, elaidoyl, or stearoyl chains into alternating layers. In summary, when all the acyl chains in a TG are the same (saturated, cis or trans unsaturated), the stable beta-phase packs into a bilayered structure. However, when the 1- and 3-acyl chains are cis unsaturated (bent) and the 2-acyl chain is either saturated or trans-unsaturated (straight), a bilayered beta'-phase can form, but transforms to a stable trilayered beta-phase, where the 2-acyl chains form a layer between two different layers of 1,3-oleoyl chains.
通过差示扫描量热法（DSC）和X射线衍射研究了对称二酸三酰甘油（TGs）、1,3-二油酰基-2-硬脂酰基（OSO）、2-反油酰基（OEO）和2-痘苗酰基（OVO）甘油的多晶型行为，并与相应的单酸TGs三油精（OOO）、三硬脂酸甘油酯（SSS）、三反油酸甘油酯（EEE）和三痘苗酸甘油酯（VVV）进行了比较。单酸TGs在所有多晶型形式中均形成双层结构。从熔体淬火时，二酸TGs OEO和OVO形成双层（D = 45 Å）β'-相，但OSO除外，它形成六方堆积的双层（D = 52 Å）α-相。在-7℃时，OSO的α-相迅速转变为双层（D = 45 Å）β'-相。在β'-相熔化温度下孵育会将OVO、OEO和OSO转变为三层（D = 65 Å）β-相，其中1,3-二油酰基链与痘苗酰基、反油酰基或硬脂酰基链分离成交替层。总之，当TG中的所有酰基链相同时（饱和、顺式或反式不饱和），稳定的β-相堆积成双层结构。然而，当1-和3-酰基链为顺式不饱和（弯曲）且2-酰基链为饱和或反式不饱和（直链）时，可以形成双层β'-相，但会转变为稳定的三层β-相，其中2-酰基链在1,3-油酰基链的两个不同层之间形成一层。
