Measurement of the degree of starch damage in flour by near infrared reflectance analysis

AbstractThe degree of mechanical damage imparted to starch granules during flour milling is of importance in relation to the baking properties of the flour. A calibration is presented which enables the degree of starch damage to be measured by near infrared reflectance. This technique is rapid and non‐destructive so facilitating quality control of a flour mill. The results obtained using 148 UK commercial flour samples were a correlation coefficient of 0.906 and a residual standard deviation of 3.5 Farrand units using 74 of the samples covering the range 6‐47 Farrand units. The calibration was obtained using log (1/R) data at 1442, 1580, 2060 and 2258 nm. The residual standard deviation increased to 4.2 Farrand units when the calibration was used to predict the values of 68 further samples of commercial flour. The wavelengths at which reflectance measurements were taken corresponded to overtones and combinations of vibration frequencies due to free and hydrogen‐bonded O—H bonds in starch.