Miller Magazine Issue: 155 November 2022

75 COVER STORY MILLER / NOVEMBER 2022 energy absorbed at the resonant frequencies for Nitrogen-Hy- drogen bonds (Protein), Oxygen-Hydrogen bonds (Water and Sugars) and the Carbon-Hydrogen bonds (Oil/Fat), are propor- tional to the concentration of each component. Only N-H, C-H and O-H bonds show absorption bands in the NIR region. Salts and minerals do not exhibit absorption bands in the NIR region and as such cannot be measured directly using NIR. However other chemical compounds in grains and oil seeds may be measured indirectly. In Europe, W and Zeleny are common measurements asso- ciated with wheat. W is a measure of the hardness of grains and Zeleny is a measure of the quality of the grain based on a sedimentation rate of flour suspended in water. There are no single NIR absorption bands for W nor Zeleny, however both W and Zeleny correlate well with grain moisture content, protein strength and grain conditioning. As such, it is reasonable to ac- cept that NIR can be used to measure W and Zeleny since NIR measures protein, starch and moisture. Likewise, water absorption and starch damage in flour can- not be measured directly based on specific absorption bands but can be measured based on the overall interaction between NIR energy and protein, starch and moisture. Falling Number is a very common parameter used by mill- ers and grain processors to evaluate the enzymatic break- down (Amylase Activity) in the grains. Millers require wheat that has a certain Falling Number value as this parameter indicates if the seeds have begun to germinate. High amy- lase activity reduces the available starch in the seeds and a reduction in the yield and quality of the flour. Falling Num- ber Apparatus consists of a constant temperature bath in which a glass tube is placed. The tube is filled with a dilute solution of water and ground grain. A ball is dropped into the tube and sensors at the bottom detect how long the ball took to drop a specific length. The longer the time period the higher the Falling Number value and the less Amylase Activity indicated. Figure 1. Near Infrared Transmission and Reflectance Schematics Figure 2. NIT and NIR Spectra of Grains and Ground Materials