The Falling Number Method
The Falling Number (FN) method has been around for decades, and it is the industry standard test for analyzing wheat and other cereal grains for pre-harvest sprouting. The FN test indirectly measures the amount of alpha amylase enzyme present in grain, due primarily to pre-harvest sprouting. Pre-harvest sprouting can take place when grain is ripe and ready to harvest and gets exposed to certain conditions, such as extended periods of rainfall or high humidity. If exposed to high moisture conditions for even a short period of time, the kernels can start to germinate, or sprout, before harvesting can take place, thus the name “pre-harvest sprouting.” Pre-harvest sprouting results in the release of alpha amylase into the inner portion of the kernel (endosperm), which begins to break down starch, resulting in low FN values. Even moderate levels of pre-harvest sprouting can impact the processing of cereal grains into breads, noodles and other products. High levels of alpha amylase can also be caused by late maturity alpha amylase (LMA), which is less common and is caused by cold or heat stress on the crop during grain fill more research in needed to better understand the extreme weather conditions that can cause LMA and the impact it has on bread making and other processes.
As stated before, the falling number method is an indirect measurement, meaning that it does not directly measure the amount of alpha amylase enzyme in the grain, but rather the effect that the enzyme has on the physical properties of the starch during the test. This test is important because most wheat purchasing contracts (domestic and export) have minimum FN specifications.
Check out our video of program manager Brian Sorenson, discussing what the falling number method is, pre-harvest sprouting, what causes high levels of alpha amylase, how the test works, history of the falling number test, who can perform the test, and where to find more information on this subject.
To learn more about the falling number method, click here to watch the USDA Federal Grain Inspection’s video on this topic.