Abstract

This study evaluated the quality and thermal stability of local and commercial vegetable oils by analyzing fatty acid-related indicators, acid value, and cholesterol content. The findings showed that all samples' fatty acid-related values with temperature. Local oils displayed comparatively low values, with Abyani sesame oil ranging from 0.193±0.017 to 0.267±0.056% and Yemeni almond oil ranging from 0.073±0.012% at 25 °C to 0.099±0.044% at 90 °C. Commercial oils showed higher susceptibility to thermal deterioration with higher values and quicker rises, especially commercial Saudi black oil (0.829 ±0.178 to 1.040±0.241) and Somalia sesame oil (0.146  ± 0.032 to 0.324 ± 0.062 %). Local oils had lower acid values; Yemeni almond oil increased from 1.571% mg KOH/g at 30 °C to 2.149±0.150% mg KOH/g at 90 °C, while Abyani sesame oil increased from 3.330±0.245 to 5.554±0.461 mg KOH/g. Commercial oils, displayed much higher values. For instance, commercial Somalia sesame oil from 7.254±1.787 to 8.964±2.456 mg KOH/g, while Saudi black oil stayed extremely high (16.69±4.365to 16.83±2.986 mg KOH/g), indicating greater hydrolysis and the generation of free fatty acids. Tehama sesame and Abyani Sesame oils had cholesterol contents of 26.53±1.735 and 26.34±2.489 ppm, respectively, which were comparatively constant and lower than other local oils. Commercial oils showed more variety, ranging from 22.42±1.676 Indian linseed to 27.28±1.983 ppm Saudi black oil. Local Yemeni fenugreek oil 38.13±1.897 ppm. Based on these results, this study compares thermal stability and quality indicators (free fatty acids, acid value, and cholesterol) of local versus commercial vegetable oils in Yemen as reliable indicators for assessing the quality and oxidative stability of sesame seed oils, with implications for quality and consumer health awareness.