利用核磁共振方法测定油料种子含油量

本文介绍用核磁共振方法测定油料种子含油量的基本原理,讨论了测定油料种子含油量三种方法:萃取重量分析法,近红外反射光谱法及核磁共振法的优缺点。与其它两种方法比较,核磁共振法更为准确,重复性更好。 宽线核磁共振技术测量种子中与油分和水分有关的总的氢含量,而与非油物质中的氢无关。如果种子干燥后再进行测量,则仪器的响应正比于种子中油含量。 而脉冲核磁共振方法,种子不需要干燥和称重。它是测量油料种子的固相(蛋白质和碳水化合物)和液相(油)的自由感应衰减(FID)信号。固相横向弛豫时间T_2远比液相短,这使我们有可能将两种信号分开,从而确定种子含油量。 与宽线核磁共振方法相比,脉冲核磁共振方法测量速度更快,更准确,它已用于种子的快速,非破坏检测,这一方法的推广有助于改进油料作物的选种和育种工作。

DETERMINING THE OIL CONTENT IN OILSEEDS BY NMR METHOD

This paper introduce the principle fundamentals of determining oil content in oilseeds by NMR method. Discussed the advantages and disadvantages of the three methods; extraction -gravimtris (AOCS), near-infrared reflectance (NIR) spectrorscopy and unclear magnetic resonance (NMR) ,. for the determination of oil content of oilseeds. The NMR method was more precise and reproducible than the other 2 methods,The wide-line NMR technique measures total hydrogen associated with the oil and water in seed independent of the hydrogen associated with the non-oil matrix. If the measurement is made on dry seed.the response of the apparatus is dirddtly proportional to the quantity of oil present in the seed.For pulsed NMR method seeds is not necessary to be over dried and weighed. It is based on the measurement of the free induction decay (FID) signal of the solid phase (protein and carbo hydrate) and the liquid phase (oil) of oilseed. The transversal relaxation time T 2 of the solid phase is much smaller than that of the liquid phase, which enables the separation of the two signals , thus ditermining oil content in oilseeds.Pulsed NMR is faster and more accurate then wide -line NMR method. It has been used for rapid and nondestructive determination of oil in oilseeds, which is of great help in oilcrop improvement programs for selecting seed and plants of higher oil content among thousands of progenies.