Title

Extraction of oil from seed of moringa oleifera using supercritical carbon dioxide

Date of Publication

2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemical Engineering

Subject Categories

Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Abstract/Summary

The study involved the extraction of oil from Moringa oleifera (MO) kernels using supercritical fluid extraction (SFE) technique. The combination of operating parameters such as extraction condition, loading configuration, and SC-CO2 with ethanol addition for substrate pre-treatment provided a high yield. The study included the comparison of different extraction methods such as SC-CO2, SC-CO2-EtOH, Soxhlet extraction using n-Hexane (SEH), cold press method (CP) in terms of oil yield, fatty acid composition, phytochemicals and physical properties of the extracted oil. Furthermore, the study explored the mass transfer relationship of extraction in terms of the solubility behavior as well as the simulated behavior from the solubility models, and evaluated the mass transfer coefficients in the form of dimensionless numbers. The experiments were conducted in the pressure range of 1530 MPa, 3560 oC temperature range, average particle size of 0.161.12 mm, EtOH ratio of 0-90 %w/w and CO2 flow rate of 0.5 m3/h. Extraction of oil from Moringa oleifera kernels using supercritical carbon dioxide with EtOH for pre-treatment of material and arrangement of material into multiple layers is promising. Adding 60% EtOH for substrate pretreatment, increased 10% in the yield. Loading the seeds in multiple-staged trays increased to as much as 26.89% in the yield against randomly packed configuration. Response surface methodology, predicted an optimal oil yield of 37.84% at a pressure of 28.97 MPa, 44.30 C temperature, and particle size of 0.54 mm. The combination SC-CO2-EtOH and multiple layered arrangement improved the yield of the SFE and is comparable to the yield obtained by SEH but higher than that of CP. While, the oil obtained from SFE method is non-toxic, and ready to use, that of the other methods has to be purified to remove the toxic solvent and the residual gums. The quality of the oil obtained in terms of fatty acid composition, refractive index, specific gravity is similar to that of commercial oil and the oil obtained from SEH. In addition, a phytochemical, glyceryl mono-oleate (GMO) which has been utilized for the preparation of the controlled 3 release systems and in topical and mucosal drug delivery systems was identified in the oil. Furthermore, the fatty acid composition of fractionated oil samples at particular intervals during SFE process was performed. Short chain fatty acids decreased during extraction period. All C18 fatty acids did not change significantly. Longer chain fatty acids increased. Though the variation of some fatty acids composition with fractionation is significant, the impact on oil solubility is however minimal because the unchanged C18 fatty acids were predominant in the oil. Solubility behavior of MO oil in SC-CO2 with variation of pressure from 15 to 30 MPa and temperature from 35 to 60 oC was investigated. The crossover pressure point of the oil where the behavior of solubility with variation of temperature change from contra-variation to co-variation was found approximately at 26.38 MPa. In addition, modelling solubility behavior of MO oil in SC-CO2 was conducted. Del Valle-Aguilera model showed the best fit with experimental data with the root mean square percentage deviation of 6.18%. It suggests that the model can be applied not for MO oil but high oleic oil solubility in SC-CO2. Furthermore, mass transfer of the MO oil in SC-CO2 was investigated with computed value of the mass transfer coefficient in the range of 2.4902x10-5 to 2.5614x10-5 corresponding to the variation of temperature from 35 to 60 oC and pressure from 15 to 30 MPa. The result agrees with the previous studies therefore, it can be used for estimating the mass transfer process of MO oil in SC-CO2.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG005264

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer optical disc ; 4 3/4 in.

Keywords

Moringa oleifera; Oilseeds

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