FATTY ACID

The physicochemical quality of commercially and locally extracted Sesamum indicum (sesame) and Gossypium hirsutum (cottonseed) oils was compared in this study, with an emphasis on three important freshness and stability indicators: acid value (AV), percentage free fatty acid (%FFA), and peroxide value (PV). These factors are essential for evaluating edible oils' hydrolytic and oxidative rancidity, which have a direct bearing on shelf life, consumer safety, and nutritional quality. Samples of oil were collected in Benin City, Nigeria, from both commercial and artisanal sources. AV, %FFA, and PV were measured using standard titrimetric and iodometric techniques, and SPSS version 30.0 was used for statistical analysis with a significance level of p < 0.05. Significant differences between the various oil samples were found in the results. In terms of freshness and oxidative stability, manually extracted sesame oil showed the lowest values in all indices (AV: 2.165 ± 0.3707 mg KOH/g; %FFA: 1.357 ± 0.2249; PV: 6.361 ± 0.7573 meq/kg). On the other hand, commercially extracted sesame oil showed much higher AV (12.9067 ± 0.6792 mg KOH/g), %FFA (6.759 ± 0.2702), and PV (45.3847 ± 1.1737 meq/kg), indicating increased lipid degradation, perhaps as a result of exposure to high temperatures and metal contaminants during industrial processing. Cottonseed oil showed the poorest quality profile, with AV (23.3043 ± 3.021 mg KOH/g), %FFA (11.722 ± 1.5195), and PV (99.586 ± 0.8009 meq/kg), reflecting high susceptibility to oxidative rancidity and limited storage stability. The findings are consistent with previous research showing that oil integrity is significantly impacted by extraction method, seed moisture, and storage conditions.

The quality of edible oils is a critical factor for consumer health, yet deterioration through hydrolysis and oxidation can lead to rancidity and the formation of toxic compounds. This study aimed to evaluate and compare the quality of commercially available Glycine max (Soya Bean Oil), Elaeis guineensis (Palm Kernel Oil), and Gossypium hirsutum (Cotton Seed Oil) by determining key degradation indices. Oils were extracted from seeds sourced from a local market using the Soxhlet method. The acid value (AV), percentage free fatty acid (%FFA), and peroxide value (PV) were determined in triplicate for each oil sample using standard titrimetric methods (AOCS). The results revealed profound disparities in quality among the oils. Soya Bean Oil exhibited acceptable quality, characterized by a low acid value (3.35 ± 0.03 mg KOH/g), low %FFA (1.68 ± 0.02%), and a moderate peroxide value (13.07 ± 0.92 meq/kg). In stark contrast, Palm Kernel Oil and Cotton Seed Oil were of exceptionally poor quality, displaying extremely high acid values (23.30 ± 3.02 and 26.13 ± 2.75 mg KOH/g, respectively) and alarmingly high peroxide values (99.59 ± 0.80 and 107.49 ± 3.78 meq/kg, respectively). These findings indicate that while the SBO was of acceptable quality, the palm kernel oil and cotton seed oil samples exhibited severe hydrolytic and oxidative rancidity, far exceeding international safety standards and rendering them unsuitable for consumption. This study highlighted a critical public health issue regarding the quality of some oils available in local markets and underscores the urgent need for stricter quality control measures throughout the supply chain to mitigate health risks associated with consuming degraded oils.