Potentials of enhancing the physicochemical and functional characteristics of <em>Nigella sativa</em> oil by using the screw pressing technique for extraction

Abstract

SUMMARY:In the current investigation the crude oil of Nigella sativa was extracted from seeds using hydraulic and screw pressing techniques. Different parameters were evaluated in order to find out the appropriate technique to enhance the physicochemical and functional-related characteristics of the extracted crude oil. Results showed that the acid and peroxide values were significantly lower in the screw pressed oil (SPO) than in the hydraulic pressed oil (HPO). The total phenolic content of the SPO was significantly higher than that of HPO. Evaluation of the oxidative stability using the Rancimat test showed that SPO recorded a much higher oxidative stability index (40.07 h) than HPO (0.51 h). The yield of the volatile oil fraction and its contents of thymoquinone isolated from the SPO were higher than that from the HPO. Biological evaluation revealed that the SPO had significantly higher antimicrobial activity than HPO against Listeria monocytogenes and Staphylococcus aureus at 40 µL/well. KEYWORDS : Crude oil; Functionality; Hydraulic pressing; Nigella sativa; Screw pressing RESUMEN: Mejoras potenciales de las características físico-químicas y funcionales del aceite de Nigella sativa mediante extracción con prensa de tornillo. En la presente investigación se extrajo el aceite crudo de Nigella sativa de las semillas utilizando técnicas hidráulicas y de prensado de tornillo. Se evaluaron diferentes parámetros para conocer la técnica apropiada que potencie las características fisicoquímicas y funcionales del aceite extraído. Los resultados mostraron que los valores de ácido y peróxido fueron significativamente más bajos en el aceite de presión con tornillo (SPO) que en el aceite prensado hidráulico (HPO). El contenido fenólico total del SPO fue significativamente mayor que el de HPO. La evaluación de la estabilidad oxidativa mediante Rancimat demostró que el aceite SPO tiene un índice de estabilidad oxidativa mucho más alto (40,07 h) que el HPO (0,51 h). El rendimiento de la fracción volátil y su contenido de timoquinona aislada del aceite SPO fueron superiores a los del HPO. La evaluación biológica reveló que el aceite SPO tenía una actividad antimicrobiana significativamente mayor que el HPO contra Listeria monocitogenes y Staphylococcus aureus a 40 μL/pocillo.

Hepatic Regeneration and Reno-Protection by Fish oil, <i>Nigella sativa</i> Oil and Combined Fish Oil/<i>Nigella sativa</i> Volatiles in CCl₄ Treated Rats

“…This volatile oil contains a major component namely thymoquinone TQ in addition to p-cymene which are considered to be responsible for the protective effect of that volatile oil fraction and its parent crude oil that bears that volatile fraction 13,15 . The content of TQ and p-cymene in the current investigation reached 68.13 and 20.11 , respectively of the total volatile oil composition, as determined by full GC analysis that was illustrated in our recent study 17 .…”

“…Therefore it can be comfortably indicated that the chemical composition of the volatile oil and its content of TQ and p-cymene in the current study is exactly the same as that illustrated before 17 . One should also bear in mind that the other non-volatile components of the whole crude oil of N. sativa like the vitamin E, phytosterols and linolenic acid can also participate beside the volatile oil fraction in the hepato-renal improvement effect of that crude oil due to their anti-inflammatory and/or antioxidant activities 14 .…”

“…The crude oil of N. sativa was extracted from the seeds according to the previous study 17 . In detail, the seeds were exhaustively pressed for two successive cycles by using a commercial scale expeller screw pressing machine located at the same herbal retail store from which the seeds were purchased.…”

“…2.6 Isolation of N. sativa volatile oil from its parent crude oil Part of the whole crude oil of N. sativa which was obtained from the previous extraction step was subjected to a hydro-distillation process as described in the same previous study 17 to isolate its volatile oil fraction. In detail, 100 g of the crude oil which is corresponding to 500 g seeds was mixed with distilled water 1:7 w/v, respectively in a 5 liter round-bottom flask and distilled for three hours using the Clevenger-type apparatus.…”

Formulation of Multi-Functional Omega-3 Oil Rich Microcapsules by Spray Drying Methodology.

“…Flaxseed oil was extracted from the corresponding seeds by using hydraulic pressing at room temperature as described by Ustun et al [18], and modified by Hamed et al [19]. Briefly, the dry seeds were milled into a fine powder, then batches of the powder, 250 g each, were wrapped in a thick heavyduty cloth and the oil was extracted using an in-house made hydraulic laboratory scale pressing machine manufactured at the National Research Centre, Cairo, Egypt and operated at its maximum pressure (3500 psi) for 1.0 h at room temperature.…”