硅胶柱层析精制中长链结构甘油三酯

为探究硅胶柱层析在中长链结构甘油三酯（MLCT）精制方面的应用,以亚麻籽油和中链脂肪酸甘油三酯为原料合成MLCT粗产品,采用硅胶柱层析进行精制,优化精制工艺条件并对硅胶柱层析精制前后MLCT的质量指标进行了测定。通过硅胶薄层层析确定硅胶柱层析的洗脱剂,通过洗脱曲线确定洗脱液收集体积,以甘二酯脱除率和产品回收率为评价指标,确定洗脱流速和上样量。结果表明：以正己烷-无水乙醚（体积比5∶ 1）为洗脱剂,等梯度洗脱,洗脱流速2.0 mL/min,上样量4 g,硅胶40 g,收集洗脱液500 mL条件下对MLCT粗产品进行精制,所得产品甘二酯脱除率达到99.40%,MLCT回收率为95.07%。精制后产品酸值（KOH）和过氧化值显著降低,分别为0.04 mg/g和0.00 g/100 g,色泽变浅,色值为R0.0,Y0.1。硅胶柱层析具有同时脱除副产物,降低酸值、过氧化值、脱色等综合效果,在MLCT精制方面有良好的应用前景。     

High-resolution NMR of irradiated almonds

Electron beam-irradiated peeled almonds (dose rate <5kGy) were subjected to a sensory test, ESR, and solid state ¹H and ¹³C NMR spectroscopy using an improved magicangle probe. In the sensory test, changes were detected only for high radiation doses, and these were similar to those produced by aging. ESR detected significant differences between irradiated and nonirradiated samples, although these differences in free radical content tended to disappear with aging. Slightly higher DG content was detected in the irradiated sample by high-resolution solid-state NMR spectra.