Evaluation a commercially available capacitive sensor for assessing the quality of palm olein used for frying

The potential of using a high-frequency capacitive sensor to monitor the palm olein quality deterioration with continuous heating at frying temperature was tested. The food manufacturers need a convenient and affordable method to determine the quality of edible oil used for culinary purposes. This study was carried out to evaluate the suitability of a low cost commercially available capacitive sensor to assess the quality of palm olein during and after frying. Palm olein was heated at frying temperature (180 °C) continuously in a deep fryer and 18 samples were collected at the time intervals of 0.0, 0.1, 0.3, 0.9, 2.5, 6.7, 9.1, 12.3, 16.5, 22.3, 30.1, 40.7, 54.9, 74.1, 100.1, 135.1, 182.3, and 246.1 hours. The change in physical and chemical oil quality parameters such as colour, refractive index (RI), viscosity, density, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) were measured from standard analytical methods and total polar matter (TPM) was measured from Testo 270 rapid test kit. Dielectric properties of the collected oil samples were measured using a high-frequency capacitive sensor. Among tested parameters, TPM had the highest sensitivity 4.23% in the range 0-25%. Therefore, Analog to Digital Conversion Value (ADCV) from high-frequency capacitive sensor can be effectively used in detecting the quality of palm olein with prolonged heating at frying temperature of 180 °C.