Measurement of the sugar contents of fruit juices and drinks by ultrasonics

The relationships between ultrasonic velocity and concentrations of glucose, fructose, sucrose, and mixed solution of glucose and sucrose were determined by experimental equipment based on ultrasonic transmission properties for liquid food quality measurement. The results indicate that the concentrations of glucose, fructose and sucrose are significantly correlated with ultrasonic velocity by quadratic polynomial (R²>0.997). The binary and quadratic polynomials of ultrasonic velocity and the concentrations of compositions in mixed solution were obtained. The relationship between them was very closely correlated (P<0.0001). There was no significant difference (P≤0.05) in concentrations of reduced sugar, sucrose and total sugar determined by ultrasonics solved from the coupled equations of empirical equation and half-empirical equation, HPLC and traditional chemical methods in nine brands of fruit drinks. It was concluded that it should be possible to mearsure exactly different sugar concentrations in drinks by ultrasonics.