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The seeds of Nigella sativa L. (Ranunculaceae), commonly known as black cumin seeds and Habat Al-barkah in Saudi Arabia, are used extensively for flavouring and medicinal purposes. This work reported the study of physiochemical properties of Saudi black cumin seed oil (BCSO). The results of hexane extraction showed that black cumin seeds are rich in oil (43.7%). All the oil samples show high saponification values and low unsaponification values. High iodine values (122.7 mg/100 g) showed high degree of unsaturation (86%) for Saudi BCSO with about 60% of dominant linoleic acid (C18:2). The volatile compounds presence in Saudi BCSO were extracted using steam distillation method and analyzed using gas chromatography mass spectrometer (GC/MS). The results showed that the volatile compounds such as p-cymene (31.50 ± 0.51%) and thymoquinone (25.35 ± 0.37%) were dominantly high in Saudi BCSO. Other compounds such as 3,5-dimethyl cyclohexanol, α-thujene, carvacrol, paeonol and longifolene were also present. Vitamin E was analyzed using High performance liquid chromatography (HPLC)-fluorescence method. The total concentrations of vitamin E were 451 ppm. The Saudi BCSO showed high content of linoleic acid (59.8%). The HPLC results showed that major triacylglycerols (TAGs) of Saudi BCSO were 1-oleoyl-2,3-dilinoleoylglycerol (OLL; 37.7 ± 0.4%) and 1,2,3-trilinoleylglycerol (LLL; 35.9 ± 0.3%). On the other hand, minor TAGs present were 1-palmitoyl-2,3-dilinoleylglycerol (PLL; 6.7 ± 0.9%), 1,2,3-trioleylglycerol (OOO; 6.4 ± 0.5%) and 1,2-dioleyl-3-linoleylglycerol (OOL; 5.7 ± 1.1%). The Saudi BCSO exhibited specific physicochemical properties and might be used for medicinal applications.

The objective of the current study was to separate saturated fatty acids (SFAs) from high free fatty acid crude palm oil fatty acid mixture using the methanol crystallisation method. The development of methanol crystallisation method procedure was based on various parameters. The fatty acid composition was determined by using gas chromatography-flame ionisation detector (GC-FID) as Fatty Acid Methyl Esters. The highest percentage of SFAs was more than 89% with the percentage yield of 48.9% under the optimal conditions of the fatty acids-to-methanol ratio of 1:15 (w/v), the crystallisation temperature of −15 °C, and the crystallisation time of 24 hours, respectively. After a double crystallisation, the composition of separated SFAs contains 90% of palmitic acid (C16:0) as a major component and 5.8% of stearic acid (C18:0), respectively. Moreover, almost 4.2% of oleic acid (C18:1) was observed in the saturated solid product. Based on the results, the use of methanol as a crystallisation solvent is recommended because of its high efficiency, low cost, stability, obtainability, and comparative ease of recovery.

The physicochemical properties of different grades of Malaysian crude palm oil (high free fatty acid crude palm oil (HFFA-CPO) and low free fatty acid crude palm oil (LFFA-CPO)) were analyzed in this study to determine their applicability as edible oils. The percentages of free fatty acids (FFAs%), iodine value, hydroxyl value, unsaponifiable value, moisture content for HFFA-CPO and LFFA-CPO were 8.7 ± 0.3 and 3.8 ± 0.1%; 53.1 ± 0.4 and 56 ± 0.3 g I2/100 g; 32.5 ± 0.6 and 18.5 ± 0.9 mg KOH/g oil; 0.31 ± 0.01 and 0.46 ± 0.02%; 0.31 ± 0.01 and 0.33 ± 0.01%, respectively. The fatty acid compositions were determined using a gas chromatography-flame ionization detector (GC-FID). The results showed that the dominant fatty acids are palmitic acid (43.2%–44.4%) and oleic acid (39.8%–41.4%). The major triacylglycerols (TAGs) of HFFA-CPO and LFFA-CPO estimated using high-performance liquid chromatography (HPLC), were POP (30.8%–33.6%) and POO (24.9%–29.7%). In general, the physicochemical properties of HFFA-CPO and LFFA-CPO are consistent with the standard Malaysian crude palm oil, with the exception of FFAs%, hydroxyl value, moisture contents.