Institute of Analytical Chemistry of the ASCR, 602 00 Brno, Czech Republic.
J Sci Food Agric. 2011 Dec;91(15):2756-61. doi: 10.1002/jsfa.4518. Epub 2011 Jun 29.
In barley, starch occurs in the form of granules with bimodal size distribution. Enzymatic hydrolysis of the starch granule is one of the most important reactions occurring during malting and mashing. Previous studies revealed the discrepancies in the assumption that barley varieties with better malting qualities should have a higher A/B (large/small starch granules) ratio. This led us to focus our attention on detailed analysis of two barley varieties, Jersey and Tolar, both with high malting quality but significantly differing in A/B (1.28 and 0.66, respectively), were chosen for more detailed analysis in the actual work. In this study, the capacity of gravitational field flow fractionation (GFFF) to monitor amylolysis of the starch granules was investigated.
Isolated starch granules from these two barley cultivars were treated with amylases. The changes in starch granule size and bimodal distribution were studied by GFFF. Simultaneously, free sugars released during enzymatic digestion were observed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The changes in the fractogram and in the mass spectra reflect a correlation with the progress of enzymatic hydrolysis.
The results show the interest in utilization of GFFF as a simple and cheap method for monitoring changes in the distribution of the starch granule size during amylolysis.
在大麦中，淀粉以具有双峰粒径分布的颗粒形式存在。淀粉颗粒的酶水解是发芽和糖化过程中最重要的反应之一。先前的研究表明，假设具有较好制麦品质的大麦品种应该具有更高的 A/B（大/小淀粉颗粒）比值存在差异。这促使我们将注意力集中在对两个大麦品种（泽西和托拉尔）的详细分析上，这两个品种的制麦品质都很高，但 A/B 差异很大（分别为 1.28 和 0.66），因此在实际工作中选择了这两个品种进行更详细的分析。在这项研究中，研究了重力场流分级（GFFF）监测淀粉颗粒淀粉酶解的能力。
用淀粉酶处理来自这两个大麦品种的分离淀粉颗粒。通过 GFFF 研究了淀粉颗粒大小和双峰分布的变化。同时，通过基质辅助激光解吸电离飞行时间质谱观察酶消化过程中游离糖的释放。指纹图谱和质谱的变化反映了与酶水解进程的相关性。
结果表明，利用 GFFF 作为一种简单廉价的方法监测淀粉酶解过程中淀粉颗粒大小分布变化具有一定的意义。
