Non-destructive Continuous and Simultaneous Estimation of Moisture and Salt Contents in Butter by the Combination of Specific Gravity and Dielectric Constant

Abstract

A method to estimate moisture and salt contents in butter continuously non-destructively and simultaneously in a process, was investigated. According to the expectation that salt and moisture contents are independently related to specific gravity and the dielectric constant with the first term linear formula, some experiments were carried out to confirm the expectation. Butter with different moisture and salt content was prepared continuously by modulating the injection volume of water and Salt, and its dielectric constant, specific gravity, moisture content and salt content were measured. The dielectric constant was measured with electrodes installed in the outlet pipe of finished butter, and specific gravity was measured with the oscilation density meter installed after a samp1ing pump on the branch line connected to the outlet pipe of butter. The butter ejected from the density meter was analyzed with respect to moisture and salt contents by mean of the drying method and the Mohr's method, respectively. The results of non-salted butter showed that the moisture content could be estimated with the linear regression formula of the dielectric constant. Furthermore the better estimation of moisture content was possible with complex linear regression formula of the dielectric constant and specific gravity. Also, the results of salted butter showed that both the moisture content and the salt content could be estimated satisfactorily by mean of different complex linear regression formula of the dielectric constant and the specific gravity. Accordingly, this estimating system was confirmed to be available for the simultaneous estimation of salt and moisture contents, and for the process control of butter manufacturing.