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Effect of sample preparation of wheat on Falling Number test
L. MO (1), G. Friedt (2), J. Hu (3), G. Guo (3) (1) Ardent Mills Wheat Research and Quality, Denver, CO, U.S.A.; (2) Ardent Mills, , NE, U.S.A.; (3) Ardent Mills Wheat Research and Quality, , CO, U.S.A..

The Falling Number (FN) test is a popular method to indirectly study the alpha-amylase activity of wheat samples. Uniformity of the sample is crucial due to the significant effect that a small amount of sprouted kernel will have on the test results. A sample size of about 250g is usually recommended for a uniform sample. Although a smaller sample size would be preferable due to less processing time, it is not known if the sample uniformity would be preserved. Therefore, this study investigated the effect of a smaller sample size on the FN values of soft red winter wheat. Two different sample sizes of 250g (SS1) and 30g (SS2) were used for soft red winter wheat of three different reported FN values: 250sec (L), 325sec (M), and 350sec (H). Samples were first collected randomly by hand for the control (DW). The DW samples were then cleaned and discriminated into two groups: randomly collected by hand (CWC) and randomly collected with a divider (CWD). The samples were then grinded using Udy Grinder with different sieve screens (0.5- 0.8-, 1.0-, and 2.0-mm). The FN values were measured using 7g of flour from each sample. Statistical analysis was performed using JMP. There were significant differences between CWC and CWD, suggesting that sampling by hand does not replicate the randomizing behavior of the divider. Significant differences were observed between SS1 and SS2 for the L and M samples, indicating that SS2 is not suitable for preparing uniform L and M samples. However, the FN test results for H wheat of sample size SS2 were comparable to the SS1 counterpart. Therefore, the SS2 sampling size can be used reliably for measuring the FN of wheat samples which have sufficiently high FN values.