Influence of the experimental environment on the ultrasonic characterization of organic and refined edible oils

The influence of the experimental environment on the ultrasonic characterization of edible oils was investigated using two different measurement configurations. The objective was to identify the most suitable experimental setup by comparing ultrasonic attenuation, velocity, acoustic impedance and reflection coefficient measurements. The selected configuration was then applied to distinguish between organic and refined soybean oils. Measurements were first performed in a cubic glass container using an immersed ultrasonic transducer, and then in a submerged multilayer container allowing ultrasonic wave propagation under normal incidence in water. In both configurations, ultrasonic signals were generated using the pulse echo method and processed with LabVIEW and OriginPro software. Ultrasonic velocity was determined using the envelope method, whereas attenuation, reflection coefficient and acoustic impedance were obtained from filtered signals using Fourier transform analysis. The results showed only slight differences in ultrasonic velocity and attenuation between the two experimental media, while the multilayer configuration provided faster acquisition and more versatile characterization conditions. This configuration was subsequently applied to the differentiation of organic and refined soybean oils through the analysis of ultrasonic velocity and reflection coefficient as a function of temperature. Statistical analysis based on linear regression revealed strong correlations between temperature and ultrasonic parameters, enabling discrimination between the two oils. The refined soybean oil exhibited greater temperature sensitivity than the organic oil, which may be associated with physicochemical modifications induced by the refining process. These results demonstrate the potential of ultrasonic characterization as a rapid, non-destructive and reliable method for edible oil quality assessment and differentiation.