Bi-State School of Food Science, University of Idaho, 875 Perimeter Dr. MS 2312, Moscow, ID 83844-2312, United States.
Department of Plant Science, Aberdeen Research and Extension Center, University of Idaho, 1693 S 2700 W, Aberdeen, ID 83210, United States.
Food Chem. 2019 Jun 30;284:140-148. doi: 10.1016/j.foodchem.2019.01.006. Epub 2019 Jan 10.
A low falling number (FN) in wheat indicates high α-amylase activity associated with poor end-use quality. We hypothesize starch - the substrate of α-amylase, can directly influence hot flour pasting properties and its susceptibility to α-amylase, which further affects viscosity. We examined the structural characteristics of starch in three soft white spring wheat cultivars grown in Idaho in 2013 (normal FN year) and 2014 (low FN year with pre-harvest rains). Our data surprisingly show that starch in some low FN wheat was not significantly degraded by α-amylase but had developmental changes with an increased proportion of B-type wheat starch. We reconstituted wheat starch and verified that starch with an increase of B-granules has a relatively low viscosity and high susceptibility to wheat α-amylase, which further facilitates the decrease of viscosity. The influence of starch structure and starch-enzyme interaction must be considered while developing a solution to the low FN issue.
小麦降落数值低表明其α-淀粉酶活性高，与较差的终端用途品质相关。我们假设淀粉——α-淀粉酶的底物，可直接影响热面团的糊化特性及其对α-淀粉酶的敏感性，进而影响黏度。我们研究了 2013 年（正常 FN 年份）和 2014 年（收获前降雨导致 FN 低的年份）在爱达荷州种植的三个软白春小麦品种的淀粉结构特征。我们的数据出人意料地表明，一些 FN 低的小麦中的淀粉并没有被α-淀粉酶显著降解，但发生了发育变化，B 型小麦淀粉的比例增加。我们重新构建了小麦淀粉，并验证了增加 B 型颗粒的淀粉具有相对较低的黏度和对小麦α-淀粉酶的高敏感性，这进一步促进了黏度的降低。在解决 FN 低的问题时，必须考虑淀粉结构和淀粉-酶相互作用的影响。
