Microfluidic evaluation of some edible oil quality based on viscosity and interfacial tensions

Microfluidic devices were applied to investigate the adulteration of high‐quality olive oil and degradation of edible oil over frying. When the inner water flows through the sheath oil flow inside the microfluidic device at specific rates, the inner water flow will be cut into dispersed droplets by the sheath flow. Lengths of the droplets will be dependent on the viscosity and interfacial tension of the sheath oil. As olive oil is adulterated with other oil, its interfacial tension will generally keep constant while its viscosity decreases. As edible oil is used for frying, its interfacial tension will decrease while viscosity increases. As a result, the droplets’ length generated in adulterated olive oil and frying oil will be dependent on their adulteration ratio and frying grade. Experiments proved that the tiny, low‐cost microfluidic device could be preliminarily implemented to quantitatively evaluate specific oil quality.