IRIKEFE BLESSING AGHOGHO

Phenolic compounds are important phytochemicals naturally present in plant seeds and oils, where they play significant roles in antioxidant defense, oxidative stability, and overall nutritional quality. This study evaluated and compared the Total Phenol Content (TPC) of soybean (Glycine max) and palm kernel (Elaeis guineensis) seeds and their corresponding oil extracts using the Folin–Ciocalteu spectrophotometric method, with tannic acid serving as the standard. Soybean and palm kernel seeds were processed, extracted using appropriate solvent systems, and analysed at 760 nm. Statistical evaluation was carried out using SPSS version 21. Results showed that the dried seeds of both plants contained appreciable phenolic levels, with soybean seeds recording 98.4 ± 1.60 g TAE/kg and palm kernel seeds showing a higher but statistically non-significant value of 135.6 ± 15.9 g TAE/kg (P>0.05). In contrast, their oil samples demonstrated markedly reduced phenolic concentrations. Soybean oil contained 0.83 ±0.17 g TAE/kg, while palm kernel oil exhibited significantly higher phenolic content of 2.71 ± 0.12 g TAE/kg (P<0.05). This notable reduction from seed to oil indicates that oil processing particularly heat treatment, solvent extraction, bleaching, and refining results in substantial loss of heat-sensitive phenolic compounds The findings reveal that although both soybean and palm kernel seeds are naturally rich in phenolic compounds, their refined oils contribute minimally to dietary phenolics. Palm kernel oil retained more phenolics than soybean oil but still exhibited drastic reduction compared to the seeds. This underscores the impact of extraction and industrial processing on the phytochemical quality of edible oils. The study suggests that adopting less-intensive extraction techniques, such as cold-pressing or minimal refining, may help preserve phenolics and improve the antioxidant capacity of plant-derived oils. Overall, this research provides valuable biochemical insight into the phytochemical composition of two widely consumed oil sources and highlights the importance of processing conditions in determining their nutritional and functional value.