For a number of years GrainGrowers has received feedback from growers voicing concerns with the use of the falling number test to measure weather damage at receival. Concerns raised range from the appropriateness and usefulness of the test to training and variability amongst test operators and receival stands to practical issues including the delays experienced at receival points when the test is in use. Questions have been raised about the availability or development of an alternative test that could be used to avoid the issues experienced with the falling number test.
What is the falling number test?
The falling number test is used to measure damage caused by germination (sprouting) of grain after rain at harvest. Germination causes an increase in the enzyme alpha-amylase which breaks down starch. The impact of this damage is not seen until the grain is processed into bread or noodles or used for malting. The falling number test was designed to mimic the way the flour made from grain would behave in a bakery and was developed in the early 1960s. The test has widespread recognition in the trade, both domestically and internationally, and it is common practise for the test to be referred to in contracts and used by buyers to specify quality.
What are the alternatives?
Over the years several alternative technologies have been developed or studied as an alternative test for alpha-amylase and germination damage, including:
- Rapid Visco Analyzer (RVA) - A specialised instrument that produces a measurement of viscosity, similar to the falling number test.
- Enzyme assays - A lab-based test for the presence or quantity of a specific enzyme.
- Immunoassays - Uses antibodies that are specifically developed to bind to particular proteins (like a rapid antigen test or RAT).
- Near-infrared (NIR) spectroscopy - Uses near-infrared light to look for chemical signatures and is currently used to measure protein, moisture and oil in grain.
- Hyperspectral imaging - Combines aspects of NIR spectroscopy and digital imaging.
- Compression time - Measures the behaviour of grain under compression.
Apart from RVA, there are not currently any alternative tests available or in the late stages of development that offer a direct replacement for the falling number test. Image recognition technology has advanced rapidly over recent years, and several systems have been developed to assist in assessing grain quality including weather damage and sprouting. The technology developers have suggested that it could be used to provide an equivalent measure to the falling number test, although this still needs to be demonstrated. Some reservations exist about this technology as current visual inspection cannot always pick up germination damage. However, this technology is rapidly developing and is likely to become more widespread in assessing various aspects of grain quality. GrainGrowers will continue working to better understand the development and use of these tests, including what might be required to support the use and development of alternative tests.