Deacidification Of Oil Research Articles

De-acidification of sunflower oil by solvent extraction: (Liquid + liquid) equilibrium data at T = (303.15 and 313.15) K

Short chain alcohols such as ethanol and methanol were used for extraction of oleic acid from sunflower oil. (Liquid + liquid) equilibrium data for the systems (sunflower oil + oleic acid + methanol) and (sunflower oil + oleic acid + ethanol) at T = (303.15 and 313.15) K are reported. The experimental (liquid + liquid) equilibrium data were satisfactorily correlated using the UNIQUAC activity coefficient model to obtain the binary interaction parameters. The experimental and calculated compositions of the equilibrium phases were compared and the relative mean square deviations (RMSD) are reported. The partition coefficients and the selectivity factor of the methanol and ethanol were calculated and presented. The experimental results indicate that increasing the temperature increases the distribution coefficient but decreases the selectivity factor. Our experimental results indicate that a possible alternative to reduce energy consumption is de-acidification of sunflower oil through liquid–liquid extraction by short chain alcohols, as this process is carried out at room temperature.

PRODUCTION OF REFINED CAROTENE‐RICH PALM OIL FROM PALM MESOCARP (ELAEIS GUINEENSIS) USING SUPERCRITICAL CARBON DIOXIDE

ABSTRACT Simultaneous extraction, degumming and deacidification of palm oil directly from palm mesocarp using supercritical carbon dioxide (SC‐CO2) were carried out. The temperatures and pressures used were 40–80C and 18–30 MPa, respectively. The degummed and deacidified palm oil produced from the process meets the specifications of refined, bleached and deodorized palm oil of Malaysian standard, with added value in its carotene content . The recovery of the refined palm oil was 52.8–74.0% based on the total hexane extractable material. Other palm minor components such as vitamin E, phytosterols and squalene were preserved in the refined SC‐CO2‐extracted carotene‐rich palm oil. The solubility of triacylglycerols (TGs), distribution coefficient of free fatty acids (FFAs) and the separation factor of FFAs and TGs of palm oil in SC‐CO2 are discussed. PRACTICAL APPLICATIONSThe study provides an alternative processing method for palm oil extraction and refining industries. The same principles could be applied to oilseed processing such as soybean and rapeseed oils. The separation factors of free fatty acids (FFAs)/triacylglycerols and the distribution coefficient of FFAs are useful data for process modeling. The extractability and extraction patterns of palm minor components in the mesocarp provide an insight for the recovery of these valuable functional components from palm oil.

Phase equilibrium for systems composed by refined soybean oil + commercial linoleic acid + ethanol + water, at 323.2 K

The present paper reports liquid–liquid equilibrium data for the system refined soybean oil + commercial linoleic acid + ethanol + water at 323.2 K. The deviation between experimental and calculated compositions, using NRTL equation, presented a maximum value of 1.21% and an average of 0.82%. The obtained parameter set enables the simulation of liquid–liquid extractors for edible oil deacidification.

Deacidification of Vegetable Oils by Solvent Extraction

The refining of edible oils requires a series of purification steps, with the most important being the decrease of the free fatty acid level of the crude oil. This step is very important for the quality of the final product and has a major impact on the economic feasibility of the whole process. Several techniques, alternative to the conventional caustic or steam distillation methods, are suggested in the literature, such as supercritical extraction, membrane technology and solvent extraction. In the present paper we discuss the main aspects related to the solvent extraction technique, coupled or not with the conventional methods. The reviewed patents indicate various advantages of a purification process based on the selective extraction of free fatty acids using short chain alcohols. Its technical feasibility is due to the differences in solubility of free fatty acids and neutral oil in the proposed solvents. This alternative technique does not generate waste products and can preserve nutraceutical compounds in the refined oil.

Partition of nutraceutical compounds in deacidification of palm oil by solvent extraction

The aim of the present work was to study the influence of the deacidification by solvent extraction on partition coefficients of carotenoids and tocopherols, by measuring the equilibrium data for the system palm oil + fatty acids + ethanol + water + nutraceutical compounds at 318.2 K. Partition coefficients of carotenoids and tocopherols were also correlated by the UNIQUAC model.

Grape seed oil deacidification by molecular distillation: Analysis of operative variables influence using the response surface methodology

The purpose of this paper is to study the physical refining process of grape seed oil using molecular distillation. Crude oil was submitted to three preliminary steps: water degumming, dewaxing and bleaching and to a final deacidification step that was accomplished by molecular distillation. The influence of two operative conditions in molecular distillation step was considered: feed flow (0.5–1.5 ml/min) and evaporation temperature (200–220 °C), in relation to free fatty acids content and tocopherols recovery in the refined oil. It was found that the target free fatty acids content (less than 0.1%) could be obtained at high evaporation temperatures, for all the studied feed flows. High tocopherol recovery was obtained in two regions of the domain: the region of low feed flows and low temperatures; and the region of high feed flows and high temperatures. So, it was found that it is possible to employ high feed flows (1.5 ml/min), that allow high outputs, and high temperatures (220 °C) to obtain refined oils with low enough free fatty acid content and high tocopherol recovery (in the order of 100%).

Deacidification of soybean oil using supercritical fluid and membrane technology

AbstractMembrane processing has been used for oil purification, but low flux and membrane instability are major impediments. A technique that combines membrane processing and supercritical CO2 was investigated. A specialized, high‐pressure, dead‐end membrane cell was designed, fabricated, and connected to two ISCO (Lincoln, NE) supercritical fluid extraction (SFE) systems. The cell has a base with a grooved bottom for permeate removal, plus a porous metal disc for membrane support; a cell body with threaded connections; and a cap with an inlet assembly. One SFE pump provided the appropriate pressure on the feed stream, the second maintained pressure on the permeate at a slightly lower pressure. The sample consisted of 50% TAG and 50% FFA. For example, for separations at 45°C and a transmembrane pressure of 7‐atm, the β (selectivity factor) values (TAG, FFA) for the SE and BW membranes were 0.56, 3.63 and 0.60, 2.63, respectively, whereas the β values (TAG, FFA) for the DK and NF90 membranes were 0.58, 1.37 and 0.70, 1.28, respectively.

Simulation of continuous physical refiners for edible oil deacidification

Physical refining, also known as deacidification by steam distillation, is a process in which free fatty acids and other volatile compounds are distilled off from the oil, using an effective stripping agent (usually steam) and suitable processing conditions. In general, vegetable oils are formed by triacylglycerols, free fatty acids, partial acylglycerols and some minor compounds, constituting a complex mixture. This work presents the implementation of a simulation program applied to the physical refining of edible oils, following a multicomponent-stripping tray-column design. Two singular vegetable oils, from palm and coconut, were selected. Their entire compositions were considered within the simulations, including acylglycerols and free fatty acids. To describe the required physical properties, group contribution methods and empirical equations were selected. The results were analyzed and compared with the literature in terms of neutral oil loss and final oil acidity, as a function of the processing conditions. Murphree efficiencies and entrainment were considered for each plate.

Optimization of the rice bran oil deacidification process by liquid–liquid extraction

The present paper reports the process variable influence on the losses/transfer of fatty compounds during the deacidification process of rice bran oil by liquid–liquid extraction. The influence of process variables such as free fatty acid concentration in the oil, water content in the ethanolic solvent and oil:solvent mass ratio, were analyzed using the response surface methodology, having the aim to maximize the transfer of free fatty acids and minimize the losses of neutral oil plus minor compounds. In addition, the UNIQUAC equation was used to predict the transfer/losses of fatty and nutraceutical compounds to the alcohol phase. Both methodologies, the mathematical model from non-linear multiple regression and the UNIQUAC model, presented good agreement with the experimental data.

Membrane-based simultaneous degumming and deacidification of vegetable oils

An efficient membrane based process for simultaneous degumming and deacidification of vegetable oil was investigated. Appropriate crude oil conditioning allow the formation of submicronic aggregates, composed with soaps molecules resulting from the neutralisation of FFA and PL, which are retained when microfiltrating. Initial flux for the 0.8 μm membranes (∼560 l/h m 2) was about twice that of the 0.5 μm and about 10 times that of 0.2 μm membrane. The filtered oils showed good quality in the case of 0.2 and 0.5 μm membranes, but the use of 0.8 μm membranes has allowed some soaps to pass through. Two types of crude oils behaviour were noticed. Oppositely to some oils for which just simple neutralisation led to a satisfactory elimination of the phospholipids, others were very tough to refine. The operating pression seems not to affect the efficiency of the separation, whereas the stability of the vesicle-like aggregates is found to be greatly affected by the increase of the temperature above 25 °C. Beside the quasi-elimination of FFA, PL and water, minerals and pigments contents were also greatly lowered. When using an NaOH 20%, the lovibond yellow score lowered from around 28 to 10 in the case of sunflower oils and from ∼34 to 6–20 in the case of soya and rapeseed oils. The monoglycerides were almost undetectable after membrane processing whatever the type of the conditioning used. After processing, the diglycerides contents, which ranges in the tested crude oils between 0.8% and 1.0%, showed almost no changes for two oils, whereas noticeable increases were obtained for the other oils. Total phytosterols contents were systematically reduced. The reductions vary from 3% to 44% upon the case. Neutralisation with an NaOH 20% lead to higher sterol losses in comparison to NaOH 40%. All the sterol components contents were found to be reduced in almost similar proportions. Industrial relevance Conventional oil recovery and purification processes are continuousely sought to be replaced by gentler processing conditions. Membrane based oil refining operating at low temperatures and without the generation of waste water offer an interesting and promising approach towards “greener” technologies.

New approaches in deacidification of edible oils––a review

In the fats and oils industry, deacidification of oils is important not only for consumer acceptance, but also because it has the maximum economic impact on production. Chemical, physical, and miscella deacidification methods have been used in the industry. There are several drawbacks associated with these conventional deacidification processes. Some new approaches that may be tried out––as alternatives to current industrial practices––are biological deacidification, reesterification, solvent extraction, supercritical fluid extraction and membrane technology. These new approaches––independently, or in combination with current technology––may be useful to overcome major drawbacks. Besides being eco-friendly, they could also lead to savings in energy and reduction in oil losses. Some of these approaches could very well replace the existing technology in the years to come.

Liquid–liquid equilibrium data for the system palm oil + fatty acids + ethanol + water at 318.2 K

Deacidification of vegetable oils can be easily performed by liquid–liquid extraction using appropriate solvents like ethanol. This paper reports experimental data for systems containing palm oil + palmitic/oleic acid + ethanol + water at 318.2K and different water contents. The addition of water to the solvent reduces the loss of neutral oil in the alcoholic phase and improves the solvent selectivity. The experimental data were correlated by the NRTL and UNIQUAC models. For systems with palmitic acid, the global deviations between experimental and calculated concentrations were 0.75% for the NRTL model and 0.61% for the UNIQUAC equation. For systems with oleic acid, the corresponding values were 1.05% and 0.84%. The adjusted interaction parameters were used to predict the equilibrium of bleached palm oil + aqueous ethanol at 318.2K, with deviation between calculated and experimental mass percentages not higher than 1.60%.

Comparison of steam and nitrogen in the physical deacidification of soybean oil

AbstractDeacidification in physical refining is one of the most sensitive steps in refining edible vegetable oils because of its large impact on the quality of the oil. The removal of volatile compounds such as FFA is accomplished at elevated temperatures and a high vacuum with a stripping gas, usually steam. The aim of this work was to verify, at the laboratory level, the advantages of using an alternative stripping gas, nitrogen, instead of steam. An ideal vapor‐liquid equilibrium model (IVLE) was used to compare the stripping capacities of steam and nitrogen and to analyze the effects of various operational parameters (temperature, pressure, amount of stripping gas) on the residual acidity of the oil. There was no clear evidence that nitrogen showed a higher capacity to strip FFA than steam. The IVLE model seemed suitable to describe FFA laboratory distillation by using steam or nitrogen, provided the final residual content of FFA was not too low.

Influence of oil conditioning on the permeate flux and cake properties during microfiltration of lampante olive oil

AbstractThis work studies the deacidification of lampante virgin olive oil (acidity ranging from 2.15–4.65%) by microfiltration through alumina membrane. The effects of (i) the amount of absorbed water during the neutralization of the free fatty acids with various NaOH concentrations, and (ii) the acid pre‐treatment with phosphoric acid on permeate fluxes during microfiltration were studied. Physical properties of the cake (specific resistance and compressibility) were also investigated. The soap molecules are known to self assemble and form multilamellar vesicles with hundreds of bilayers entrapping water molecules between the polar groups. Swelling and deformability of such structures must be influenced by the amount of solubilized water. Our results show for all tested oils that a dilute NaOH solution (20%) allows the highest flux through the membrane, i.e. about 3‐fold the flux resulting from 40%‐NaOH treatment. The improvement of the initial fluxes reached approximately 300% in comparison with those obtained with more concentrated NaOH solutions, whereas the use of a more diluted solution (10% NaOH) caused a loss of separation efficiency. The addition of 0.1% (wt/wt) of phosphoric acid prior to neutralization results in further flux improvement especially at the beginning of filtration. The initial fluxes doubled when passing from 0–0.05% H3PO4 and then, in case of 20% NaOH to 0.1%. The average cake‐specific resistance was the highest in the case of neutralization with 30% NaOH and the lowest when coupling 0.1% H3PO4 pre‐treatment with 20% NaOH neutralization. In the latter case the cake showed a highly compressible behavior.

A continuous countercurrent supercritical fluid deacidification process for phytosterol ester fortification in rice bran oil

This study examines the potential of a continuous countercurrent supercritical carbon dioxide fractionation technique for deacidification of crude rice bran oil. A pilot scale packed column was utilized for the experiments. It was shown that fractionation at low pressure, 138 Bar, and high temperature, 80 °C, effectively removed free fatty acids from crude rice bran oil without any oryzanol loss in the extract fraction. Oryzanol content of the raffinate fraction was three times higher than that of the feed material. Phytosterol fatty acid ester content of the raffinate fraction was also increased during the deacidification process, however the enrichment of these moieties was not as high as that found for oryzanol.

Liquid−Liquid Equilibrium Data for the System Corn Oil + Oleic Acid + Ethanol + Water at 298.15 K

Deacidification of vegetable oils can be performed by liquid−liquid extraction. The present paper reports experimental data for the system corn oil + oleic acid + ethanol + water at 298.15 K and different water contents. The addition of water to the solvent reduces the loss of neutral oil in the alcoholic phase and improves the solvent selectivity. The experimental data were correlated by the NRTL and UNIQUAC models, with a global deviation of 0.89% and 0.92%, respectively.

Bio‐ and auto‐catalytic esterification of high acid mowrah fat and palm kernel oil

An alternative process for the deacidification of high acid palm kernel oil (PKO) and mowrah fat, MF, was investigated by autocatalytic and enzyme (Mucor miehei)-catalyzed esterification of free fatty acids (FFA). In the process monoglyceride (MG) or glycerol was used as esterifying agent. The results of the autocatalytic esterification process were compared with that of bioesterification with respect to reduction of FFA. For the former process the optimum reaction temperature and oil to MG or glycerol proportion were established. The optimum reaction temperature for PKO free fatty acids with stoichiometric quantity of glycerol is 160-165 °C (at 10 mm Hg pressure (1.33 kPa)) and after 6 h the FFA content is reduced to 1.6%, w/w, (from 25.0%, w/w, original). However, if a stoichiometric amount of MG is used as an esterifying agent the optimum esterification temperature is found to be 195-200 °C (at 10 mm Hg pressure (1.33 kPa)), and after 8 h the FFA content is reduced to 3.4%, w/w. On the contrary, biorefining of PKO at 60 °C temperature and 10 mm Hg pressure (1.33 kPa) using optimum (40% excess) quantity of glycerol or 50% excess MG reduces the FFA level to 1.2% and 0.7%, w/w, respectively. Similar study on bio- and auto-catalytic esterification of MF was also carried out and got comparable results. The final products were then characterized. La matiere grasse de Madhuca latifolia, le beurre de mowra, et l'huile palmiste sont utilisees pour la production de succedanes de beurre de cacao. Un procede alternatif pour la desacidification de ces produits est recherche par esterification des acides gras libres, catalysee par une enzyme ou autocatalytique. Dans le procede, un monoglyceride ou du glycerol est utilise comme agent esterifiant. Les resultats de l'esterification autocatalytique sont compares avec ceux de la bioesterification en evaluant la reduction des teneurs en acides gras libres.

Deacidification of oils and fats of biological origine by aqueous solutions of tertiary amines

Deacidification of triacylglycerols by extraction is investigated using aqueous solutions of amines as extractants. Tertiary amines with boiling points ranging between 100° and 170°C, such as 2-methylamino-diethanol, 2-dimethylamino-ethanol, 4-methylmorpholine, 1-dimethylamino-2-propanol etc. were found to be suitable substances. Especially the deacidification by aqueous solutions of 2-dimethylamino-ethanol (DMAE) was amply investigated as it is used as an active agent in remedies. Amazingly gelatinous soap stocks are not formed, when the concentration of DMAE exceeds 20% if the free fatty acid content of the oil is below 15%. Two liquid phases are formed in systems composed of triacylglyceroles and aqueous solutions containing 20 to 80% DMAE. Palm oil containing 4.3 wt.% free fatty acids was mixed with an equal amount of an aqueous solution of 30 wt.% DMAE at 60°C. In equilibrium an extract containing 86 wt.% free fatty acids (solvents deducted) and a raffinate of 0.09 wt.% free fatty acids are obtained. Loss of neutral oil being 0.7 wt.%.

Deacidification of corn oil by solvent extraction in a perforated rotating disc column

AbstractThe deacidification of corn oil by continuous liquid‐liquid extraction was investigated in a rotating disc column. The solvent was ethanol containing approximately 6% water. The influence of rotor speed, oil phase flow, and column geometry upon the dispersed phase holdup and the mass transfer efficiency was studied. The dispersed phase holdup increased with the increase of rotor speed and oil phase flow. Pratt's equation was used for calculating the characteristic velocity. An inverse relation was observed between the characteristic velocity and rotor speed, which is different from data previously reported in the literature. The estimated volumetric mass transfer coefficients increased as rotor speed and oil phase flow increased. The experimental results proved that it is feasible to obtain a refined oil with an oleic acid content less than 0.3 wt% by continuous solvent extraction. They also indicated that the corresponding loss of neutral oil was less than 5 wt%. Such value for the loss of neutral oil is significantly lower than the results reported in the literature for alkali or physical refining of corn oil.

PURIFICAÇÃO DE ÓLEOS VEGETAIS POR EXTRAÇÃO COM CO2 SUPERCRÍTICO

Este estudo constatou a possibilidade de extrairem-se ácidos graxos livres de óleos vegetais com CO2 supercrítico. Utilizou-se neste trabalho óleos de soja e de castanha do Pará. A pesquisa desenvolveu-se em duas etapas, inicialmente investigou-se a possibilidade de se extrairem os ácidos graxos destes óleos em condições de extração que variaram de 50-140 bar e de 40-80oC durante 40-160 minutos. Concluiu-se que é possível realizar a desacidificação de óleos vegetais. A eficiência da extração foi de aproximadamente 30% a 140 bar e 80oC para ambos os óleos. Após esta primeira etapa, o próximo passo foi a tentativa de obter-se um aumento na eficiência do processo promovendo a pré-degomagem nos óleos brutos como uma etapa anterior ao processo de desacidificação com CO2 supercrítico. A degomagem foi realizada através de dois métodos diferentes, um para extrair as gomas hidratáveis e outro para extrair tanto as hidratáveis como as não-hidratáveis. Os resultados experimentais foram obtidos a 140 bar e 80oC durante 40-160 minutos, mostrando que a pré-degomagem é realmente necessária, pois a eficiência da extração aumentou para 57% para o óleo de soja e 42% para o de castanha do Pará totalmente degomados, sendo que o método escolhido deve extrair tanto as gomas hidratáveis como as não-hidratáveis. Finalmente, utilizou-se cossolvente (etanol a 1-5% do peso do óleo) para auxiliar a extração, observando-se um aumento na eficiência para aproximadamente 65% para o óleo de soja e 56% para o de castanha do Pará totalmente degomados a 140 bar e 80oC por 40-160 minutos.