Detection of Storage Container and Temperature Effects in Extra Virgin Olive Oil by a Sensitive Microwave Sensor in Transmission Mode

The storage conditions of olive oil, particularly the type of container and environmental factors, play a crucial role in preserving its natural quality. Improper storage may lead to adverse effects that could pose risks to human health. In this context, a range of sensors, including electronic noses, UV-VIS spectrophotometers, and gas chromatography, have been developed to analyze these factors effectively. While each of these sensors offers distinct advantages, they also have certain limitations, such as low sensitivity, complex setup procedures, and high cost, which restrict their widespread applications. In this study, for the first time in the literature, we proposed a high-quality and sensitive metamaterial (MM)-based Microwave (MW) sensor to monitor the effects of various storage containers (green PET, dark glass, and tinplate) and environmental conditions (temperature variations of 23°C and 60°C) on the electromagnetic properties of extra virgin olive oil over 90 days. The proposed sensor exhibits an outstanding quality factor (110.2) and sensitivity (12.69 %), positioning it as a leading solution compared to similar MM-based MW sensors reported in the literature. Our study reveals that the resonance frequency of the proposed sensor changes over time for oil samples stored in any container type under a given environmental condition. Additionally, oil samples stored in green PET containers exhibit a more significant resonance frequency shift, which can be attributed to their higher dielectric constant. It is also observed that the proposed sensor shows more frequency shifts for samples stored in any type of container as the temperature increases. This shift is closely linked to the intensified interaction between the oil sample and its container.