This work was dedicated to reporting the full chemical and physical characterisation of Crambe abyssinica Hochst. seed oil. The oil from the seeds was extracted using n-hexane. The seeds contain about 30 % oil. Density, refractive index, colour, smoke point, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, the relative position of fatty acids in C 1 and C 3 carbon glycerol, sterols, tocopherols, peroxide value, E 1 % 1cm at 232 nm, and the susceptibility to oxidation measured by the Rancimat method were determined. The oil was found to contain high levels of unsaturated fatty acids, especially C22:1 (63.77 %). The dominant saturated acid was C22:0 (2.14 %). The oil was also found to contain high levels of b-sitosterol (51.93 %), campestanol (21.98 %), and brassicasterol (12.35 %). a-, c-, and d-Tocopherols were detected up to levels of 7.67, 125.04, and 3.99 mg/kg, respectively. The induction period (at 110°C and 20 l/h) of the oil was 8.83 h. The relative position of fatty acids in C 1 and C 3 position was as follows: linoleic 0.45 %, oleic 8.84 %, and erucic 90.72 %. The thermal profile of the oil presented a single peak at -20.94°C.
Olive leaves (OLL), an agricultural waste by-product, are considered a significant bioresource of polyphenols, known as bioactive compounds. This study evaluates the pulsed electric field (PEF) technique for the extraction of polyphenols from OLL. The study parameters included a series of “green” solvents (ethanol, water as well as mixtures of them at a 25% step gradient) and different input values for the pulse duration of PEF. The phytochemical extraction degree was evaluated using total phenol concentration (Folin–Ciocalteu method) and high-performance liquid chromatography (HPLC) analyses, while the antioxidant activity was assessed using differential scanning calorimetry (DSC). The results obtained from the PEF extracts were compared with those of the extracts produced without the PEF application. The highest PEF effect was observed for aqueous ethanol, 25% v/v, using a pulse duration of 10 μs. The increase in the total polyphenols reached 31.85%, while the increase in the specific metabolites reached 265.67%. The recovery in polyphenols was found to depend on the solvent, the pulse duration of treatment and the structure of the metabolites extracted.
Abstract:The antimicrobial activity of the oil extracted with n-hexane from the seeds of Moringa peregrina was tested against Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans, C. tropicalis and C. glabrata. The oil proved effective against all of the tested microorganisms. Standard antibiotics (netilmycin, 5-flucytocine, intraconazole and 7-amino-4-methylcoumarin-3-acetic acid) were used for comparison. The resistance to oxidation of the extracted seed oil was also determined.
Natural antioxidants derived from plant sources attract considerable scientific interest. While classic extraction methods consume high volumes of toxic organic solvents, cloud point extraction requires surfactant not exceeding 15% of the waste volume. In preliminary tests, the suitability of various low hazard surfactants (Span 20, PEG 400, Tween 80 and 20) was explored for separation of phenols and carotenoids from olive mill wastewater and red-flesh orange juice. Tween 80 showed the highest recovery and further applied to the next experiments. The most appropriate surfactant concentrations were 5% (for olive mill wastewater) and 7% (for orange juice) as indicated by recovery % and the rest cloud point extraction parameters (analyte concentration, concentration factor, and phase volume ratio). A double step CPE with 5% + 5% of Tween 80 recovered up to 94.4% of the total phenols from olive mill wastewater, while a 7% + 7% of Tween 80 recovered up to 72.4% of the total carotenoids from orange juice. Evaluation of the final effects and extraction efficiency of single and double step cloud point extraction shows that double step scheme seems to be preferable in both cases. Finally, phenols and carotenoids recovered by Tween 80 maintained high antiradical activity (DPPH test).
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