Free Fatty Acid Detection in Heated Palm Cooking Oil Using an Open Path Optical Method

Palm cooking oil is widely used worldwide due to its affordability and excellent oxidative stability during frying. However, continuous usage of cooking oil can lead to chemical deterioration, resulting in the formation of harmful compounds for human health, specifically the presence of free fatty acids. In this study, an open-path optical technique combined with spectroscopy was employed to identify these free fatty acids (FFA). With the open-path optical approach, a beam of incident light passes through the palm frying oil sample at a specific angle before being collected by a spectrometer. The intensity of the emitted light was then evaluated using the Spectrasuite program. The research findings revealed that each heated palm oil sample exhibited a unique absorbance spectrum. The detection of free fatty acids was successfully achieved at two specific wavelengths, namely 347.50 and 364.18 nm. Notably, the detection sensitivity for heating durations of 0–3 h was found to be superior at the wavelength of 364.18 nm, as reported in the study.