Synchronous magnetic flux-induced electrical response of orange juice

The study proposes a method for measuring the electrical properties of orange juice by using two magnetic fluxes with the same frequency (or synchronous magnetic fluxes) at 400-700 Hz. The juice was passed through two spiral glass tubes, which formed the secondary coils of the transformer with different connection modes. Five measurement points (a, b, o, −a, and −b) were arranged at different terminals of the two coils to evaluate output voltages (U−aa, Uoa, U−bb, and Uob) under the fluxes. Control parameters included the excitation voltage (UP), frequency, and phase difference. Results indicated that the output voltage of the juice increased linearly with increasing excitation voltage at all points. In-phase output voltages were higher than reverse-phase output voltages. The value for λ−aa (U−aa/UP) remained stable as the excitation voltage increased. In addition, different physicochemical properties of orange juice caused a change in the output voltages, which was consistent with Ohm's law. Soluble solids content and U−bb were linearly correlated, showing R2 values at 0.875 and a root-mean-square error of 0.702 Brix° at 20 V and 700 Hz. The method showed potential for the rapid determination of the quality of liquid foods by using magnetic flux-induced electrical parameters.