In-line Measurement of Moisture Content of Wheat by Acoustic Method

Moisture content has significant effects on most properties of agricultural products. Acoustic technique is a suitable method for moisture prediction of grains and seeds, because the impact sound of seeds with a impact surface is highly affected by moisture content. In this study, a acoustic device was used to determine the moisture content of wheat grains (12‒ 32% wet basis) to the sound spectrum generated by the fall of grains over a rigid surface of known characteristics (glass, wood and galvanize iron). A microphone, which is placed underneath the surface, receives sound waves generated by kernel impact and converts them to an electronic signal. The linear equations were proposed to describe the existing relationship between acoustic property and moisture content. Glass impact surface and 10 cm drop height selected as the suitable parameters for calibration of system. The moisture content of the samples was determined using standard oven method. Results show that the moisture content measured by using acoustic technique was highly correlated with the actual values (R 2 ≥ 0.95).