Optical Properties of Palm Kernel Oil as a Potential Biophotonic Medium in Ondo State

Biophotonic media derived from plant-based oils are attracting growing research interest due to their biocompatibility, abundance, and optical transparency across specific wavelength ranges. This study characterizes the optical properties of palm kernel oil sourced from processing mills in Ondo State, South West Nigeria. Measurements of refractive index, optical transmittance, and absorption coefficients were performed using an Abbe refractometer and UV-Visible spectrophotometer on samples collected across three seasonal periods. The refractive index of palm kernel oil was found to range between 1.455 and 1.462 at room temperature, consistent with reported values for tropical seed oils but with notable seasonal variation attributed to changes in free fatty acid composition. Transmittance measurements indicate high transparency in the visible range between 400 nm and 700 nm, with significant absorption in the UV region. The study also examines how temperature variation between 25 degrees Celsius and 60 degrees Celsius affects optical density, providing thermooptic coefficient data. Findings suggest that refined palm kernel oil could serve as an inexpensive optical coupling medium for biomedical imaging applications. Comparison with commercial optical coupling gels reveals competitive transmittance profiles at a fraction of the cost. The research contributes to the growing literature on locally sourced photonic materials with applications in diagnostic optics and fiber optic coupling in Nigerian laboratory settings. Keywords: palm kernel oil, refractive index, optical transmittance, biophotonic medium, Ondo State