Using a Double Y-type Optical Fibre to Create a System for Measuring Fat Content in Cream
J. Zhang, Z. Zhao and W. Zhang
A measurement system of fat content in cream is developed by utilizing backscattering of a laser beam from the fat. The system is composed of light source, sample pool, a thermoelectric cooling (TEC) temperature controller, double Y-type optical fibre, detector, amplifier, A/D converter and microprocessor. A semiconductor laser (fibre laser) is adopted as light source of the system and silicon PIN photodiode is applied as detector. Double Y-type optical fibre is used for light transmission and the double Y-type can eliminate the influence of mirror reflection of solution’s surface. In addition, the TEC temperature controller is used to make fat particle size stay invariable. Based on the Mie theory, the backscattering light of laser is adopted as the optical parameter related to fat content in cream solution. Under the optimal experimental conditions, the calibration model of the system is established by cream samples with different fat content. In addition, limits of detection (LOD), limits of quantitation (LOQ) and repeatability of the system is obtained. According to the calibration model, a prediction is made to verify the accuracy of the system (the prediction errors within ±0.200%). As a result, the system can realize the measurement of fat content in cream.
Keywords: Fibre laser, semiconductor laser, fat, cream, double Y-type fibre, measure, backscattering, Mie scattering theory