玉米胚芽胚乳中油水动态行为的NMR研究

应用核磁共振时域二维弛豫相关谱分析的方法,对玉米胚芽的核磁共振弛豫特性进行了研究.对以下三种样品进行了测定:(1)胚芽不含油(用化学方法蒸馏出)但是含有不同百分含量的水;(2)胚芽不含水(真空蒸发)但是含有不同百分含量的油;(3)含有不同百分含量的水的胚乳水系统.研究表明随着水含量的增加水的纵向弛豫时间T₁减小,表明水与胚芽基质具有强烈的相互作用,而油的纵向弛豫时间T₁随着油含量的增加变化很小,表明油与胚芽基质之间没有大的相互作用,油几乎独立地处在胚芽中;对低水分(少于5%)玉米胚芽水系统,结果表明水是束缚于胚芽基质上,而油则是以油胞的形式存在于胚芽中.在玉米胚芽水系统中有两个T₁弛豫成分,长T₁弛豫成分从基质到水的交换率为57s^-1;从水到基质的交换率为113s^-1.短T₁成分从基质到水的交换率为245s^-1;从水到基质的交换率为821s^-1.在低水合状态下,胚乳水系统仅有一个T₁弛豫成分.胚乳到水的交换率高于37s^-1.

THE STUDY OF WATER AND OIL DYNAMICS IN CORN GERM AND ENDOSPERM BY NMR METHOD

Two-dimensional time evolution approach was appli ed to study corn germ and endosperm-water system. Measurements were made on; (1 ) germ without water (vacuum evaporation) but with different percentages of oil, (2) germ without oil(chemically extracted) but with different percentages of wa ter and (3) endospermwater system with different percentages of water. Water int eracts strongly with germ matrix and considerably decreases T-1 of the system, whereas oil almost remains independently with its surroundings. The behavior of low moisture (less then 5% of water) corn germ is the water bound to germ matrix and oil is in the form of oilcell. There are two T-1 components in germ matrix -water system. The exchange rates in long T-1 group is 57 s {-1} from mat rix to water and 113 s {-1} from water to matrix. In short T-1 group, the e xchange rate is 245 s {-1} from matrix to water and 821 s {-1} from wate r to matrix. At low hydration, the endosperm-water system has one T-1 componen t. The exchange rate from endosperm to water is higher than 37 s {-1}.