Mulia, K., Adam, D., Zahrina, I., Krisanti, E.A., 2018. Green Extraction of Palmitic Acid from Palm Oil using Betaine-based Natural Deep Eutectic Solvents. International Journal of Technology. Volume 9(2), pp. 335-344
|Kamarza Mulia||Chemical Engineering Department, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia|
|Dezaldi Adam||Chemical Engineering Department, Faculty of Engineering, Universitas Indonesia|
|Ida Zahrina||Chemical Engineering Department, Faculty of Engineering, Universitas Indonesia|
|Elsa Krisanti||Chemical Engineering Department, Faculty of Engineering, Universitas Indonesia|
In the palm oil refining processes, the free fatty acid content is reduced to an acceptable level by using steam-stripping that causes, also, the loss of nutraceuticals such as tocopherols and carotenoids. An alternative method, such as solvent extraction, to separate free fatty acids, especially palmitic acid as the major free fatty acid present in palm oil, will conserves not only the important nutraceuticals but, also, conserves energy because a steam requirement is eliminated. The objective of this research is to evaluate the performance of Natural Deep Eutectic Solvents (NADES), each consisting of betaine as the hydrogen bonding acceptor and a polyalcohol as the hydrogen bonding donor, to extract palmitic acid from palm oil. The goal is to obtain a NADES that is able to extract palmitic acid from palm oil with the highest extraction yield. The viscosity of various studied NADES was 10-236 cSt while the polarity parameter, determined by using Nile red as the solvatochromic dye, was 48.9-50.8 kcal/mol. The obtained data shows that, for NADES having similar polarity to that of betaine, the extraction yields reduce with increasing viscosity of the NADES. The highest extraction yield of 60% (w/w), corresponding to a distribution coefficient value of 0.75, was obtained by using NADES consisting of betaine and 1,2-butanediol. The extraction yield and distribution coefficient values indicated the potential of NADES, prepared by friendly compounds of betaine and polyalcohols, as alternative green solvents in the solvent extraction process when separating free fatty acids from palm oil.
Betaine; Deep-eutectic-solvent; Palmitic acid; Palm-oil; Polyalcohol
Palm oil is obtained from crude palm oil after going through the degumming, bleaching, and deacidification processes to get rid of impurities and unwanted components. Palm oil has a unique composition of saturated and unsaturated fatty acids (50:50) and contains desirable compounds such as triacylglycerols, tocopherols, tocotrienols, carotenoids and phytosterols (Edem et al., 2002). Generally, good quality oil contains more than 95% neutral triacylglycerols and 0.5% or less free fatty acids (Lin, 2002; Mba et al., 2015). The presence of free fatty acids in palm oil is undesirable because it is easily oxidized and can cause rancidity (Zahrina et al., 2018).
In some of the palm oil refining processes, valuable nutraceuticals, such as tocopherols and carotenoids, are lost or degraded in the deacidification process because of the chemicals and high temperature steam (240-260°C) used to evaporate the free fatty acids (Hamunen, 2010). It is preferable to carry out the deacidification process by using a solvent extraction method at ambient temperature and pressure because it reduces the nutraceutical compounds losses and reduces the consumption of energy (Gonçalves & Meirelles, 2004, Rodrigues et al., 2007). However, by using hydrated ethanol as a solvent for the extraction, it turns out that there is an unacceptable low amount of extracted free fatty acids (Gonçalves et al., 2007).
Rodrigues et al. (2006) reported that free fatty acids could be extracted from cottonseed oil without reducing the nutraceutical content by using ethanol as extracting solvent. The process was optimized by adjusting the ethanol/water ratio and extraction temperature. The addition of water to ethanol solvent can reduce the nutraceutical loss present in cottonseed oil. However, this process can reduce the palmitic acid content of the palm oil to only 0.3% which is still higher than the 0.1% representing the upper limit requirement for food products. Therefore, the search for an alternative solvent for the extraction of free fatty acids from palm oil continues.
Green solvents are widely used as substitutes of hazardous organic solvents in order to minimize the environmental problems and to improve safety and health and reduce the cost (Bi et al., 2013). The usage of green solvents in the extraction of natural products is known as green extraction (Chemat et al., 2012). Ionic Liquids (ILs) are used in a wide range of applications (Earle & Seddon, 2000; Earle et al., 2006; Han & Row, 2010). However, due to the high toxicity of some ILs and the high cost of their synthesis, ILs are not commonly used in the pharmaceutical and food industries (Choi et al., 2011; Angell et al., 2012; Dai et al., 2013a).
Abbott et al. (2004) reported firstly about deep eutectic solvents that had similar physical properties and phase behaviors to of ILs. Such solvents were regarded as alternatives to ILs due to their ease of synthesis, availability, biodegradability, negligible volatility, being environmentally friendly and of low cost (Zhang et al., 2012; Hayyan et al., 2013, Maugeri et al., 2012). Deep eutectic solvents can be formed by mixing a Hydrogen Bond Acceptor (HBA), such as a quaternary ammonium salt, as and one or more Hydrogen Bond Donors (HBD) such as amides, carboxylic acids and polyalcohols. The HBA and HBD form intermolecular hydrogen bonds with each other when mixed in a certain molar ratio and produce an eutectic mixture that has a lower melting point than its individual components. Dai et al. (2013b) reported the existence of Natural Deep Eutectic Solvents (NADES) by using mixtures of various cellular constituents (primary metabolites) from all kinds of organisms. NADES, which are still liquid at room temperature, have nontoxic and environmentally friendly characteristics that are used potentially as solvents for the extraction of bioactive compounds from plants (Bi et al, 2013; Mulia et al., 2015; Garcia et al., 2016).
The physicochemical properties of betaine-polyalcohol NADES and the molecular structure of polyalcohols affected the stability and performance of NADES extracting palmitic acid from palm oil. The viscosity and density of NADES from betaine and polyalcohols appeared to be influenced by the type of polyalcohols and the molar ratios of betaine-to-polyalcohols. The hydrogen bonds and free volume formation were expected to affect the value of viscosity and density. The polarity of the studied NADES was more likely to be affected by the type of polyalcohol used rather than by the molar ratio of betaine-to-polyalcohol. There is relationship between the extraction yield and viscosity, for NADES with closed polarity (ENR) to the polarity of pure betaine, i.e. the extraction yield declines with increasing viscosity of the NADES. The highest single-stage extraction yield of palmitic acid from palm oil was 60% (w/w) with the distribution coefficient of 0.75; this was obtained by using NADES from betaine and 1,2-butanediol. This study’s extraction condition was mild and each NADES was prepared from environmentally friendly compounds that were less or non-toxic to human or living things. The results indicate that NADES, prepared by friendly compounds of betaine and polyalcohols, have the prospect of being alternative green solvents in separating free fatty acids from palm oils in the solvent extraction process.
The authors are grateful for the Universitas Indonesia’s financial
support through the DRPM PITTA project, contract number 772/UN2.R3.1/HKP.05.00/2017.
Abbott, A.P., Boothby, D., Capper, G., 2004. Deep Eutectic Solvents Formed between Choline Chloride and Carboxylic Acids: Versatile Alternatives to Ionic Liquids. Journal of American Chemical Society, Volume 126(29), pp. 9142–9147
Angell, C.A., Ansari, Y., Zhao, Z., 2012. Ionic Liquids: Past, Present and Future. Faraday Discussions, Volume 154, pp. 9–27
Bi, W., Tian, M., Row, K.H., 2013. Evaluation of Alcohol-based Deep Eutectic Solvent in Extraction and Determination of Flavonoids with Response Surface Methodology Optimization. Journal of Chromatography A, Volume 1285, pp. 22–30
Chemat, F., Vian, M.A., Cravotto, G., 2012. Green Extraction of Natural Products: Concept and Principles. International Journal of Molecular Sciences, Volume 13, pp. 8615–8627
Choi, Y.H., Spronsen, J.V., Dai, Y., Verberne, M., Hollmann, F., Arends, I.W.C.E, Witkamp, G.-J, Verpoorte, R., 2011. Are Natural Deep Eutectic Solvents the Missing Link in Understanding Cellular Metabolism and Physiology? Plant Physiology, Volume 156(4), pp. 1701–1705
Dai, Y., Spronsen, J., Witkamp, G.-J., Verpoorte, R., Choi, Y.H., 2013a. Natural Deep Euthectic Solvents as New Potential Media for Green Technology. Analytica Chimica Acta, Volume 766, pp. 61–68
Dai, Y., Witkamp, G.-J., Verpoorte, R., Choi, Y.H., 2013b. Natural Deep Eutectic Solvents as New Extraction Media for Phenolic Metabolites in Carthamus tinctorius L. Analytical Chemistry, Volume 85(13), pp. 6272–6278
Earle, M.J., Seddon, K.R., 2000. Ionic Liquids: Green Solvents for the Future. Pure and Applied Chemistry, Volume 72, pp. 1391–1398
Earle, M.J., Esperança, J.M., Gilea, M.A., Lopes, J.N.C., Rebelo, L.P., Magee, J.W., Seddon, K.R., Widegren, J.A., 2006. The Distillation and Volatility of Ionic Liquids. Nature, Volume 439, pp. 831–834
Edem, D., 2002. Palm Oil: Biochemical Physiological Nutritional. Plant Foods for Human Nutrition, Volume 57, pp. 319–341
Fletcher, K.A., Storey, I.A., Hendricks, A.E., Pandey, S., 2001. Behavior of the Solvatochromic Probes Reichardt’s Dye, Pyrene, Dansylamide, Nile Red and 1-pyrenecarbaldehyde within the Room Temperature Ionic Liquid PF6. Green Chemistry, Volume 3, pp. 210–215
Garcia, A., Rodriguez-Juan, E., Rodriguez-Gutierrez, G., Rios, J.J., 2016. Extraction of Phenolic Compounds from Virgin Oil by Deep Eutectic Solvents (DESs). Food Chemistry, Volume 197, pp. 554–561
Gonçalves, C.B., Meirelles, A.J.A., 2004. Liquid–liquid Equilibrium Data for the System Palm Oil + Fatty Acids + Ethanol + Water at 318.2 K. Fluid Phase Equilibria, Volume 221, pp. 139–150
Gonçalves, C.B., Filho, P.A.P., Meirelles, A.J.A., 2007. Partition of Nutraceutical Compounds in Deacidification of Palm Oil by Solvent Extraction. Journal of Food Engineering, Volume 81, pp. 21–26
Hamunen, A., 2010. Process for Isolation of Fatty Acids, Resin Acids and Sterols from Tall Oil Pitch, US 2010/0137556 A1
Han, D., Row, K.H., 2010. Recent Applications of Ionic Liquids in Separation Technology. Molecules, Volume 15, pp. 2405–2426
Harris, R.C., 2008. Physical Properties of Alcohol Based Deep Eutectic Solvents. Ph.D. Thesis, Department of Chemistry, University of Leicester, Available online at http://hdl.handle.net/2381/4560, Accessed on 29 October 2017
Hayyan, M., Hashim, M.A, Hayyan, A., Al-Saadi, M.A, AlNashef, I.M., Mirghani, M.E.S., Saheed, O.K. 2013. Are Deep Eutectic Solvents Benign or Toxic? Chemosphere, Volume 90, pp. 2193–2195
Israyandi, Zahrina, I., Mulia, K., 2017. Optimization Process Condition for Deacidification of Palm Oil by Liquid-liquid Extraction using NADES. In: AIP Conference Proceedings 1823, 020107 (2017); doi: 10.1063/1.4978180
Lin, S.W., 2002. Palm Oil. Vegetable Oils in Food Technology. Composition Properties and Uses. In: Gunstone, F.D. (Ed), CRC Press LLC, Boca Raton, Florida. USA, pp. 59–86
Maugeri, Z., Leitner, W., de María, P.D., 2012. Practical Separation of Alcohol-ester Mixtures using Deep-Eutectic-Solvents. Tetrahedron Letters, Volume 53(51), pp. 6968–6971
Mba, O.I., Dumont, M.-J., Ngadi, M., 2015. Palm Oil: Processing. Characterization and Utilization in the Food Industry-A Review. Food Biosience, Volume 10, pp. 26–41
Mulia, K., Terahadi, F., Putri, S., Krisanti, E.A., 2015, Selected Natural Deep Eutectic Solvents for the Extraction of ?-Mangotin from Mangosteen (Garcinia mangostana L.) Pericarp. International Journal of Technology, Volume 6(70), pp. 1211–1220
Ogihara, W., Aoyama, T., Ohno, H., 2004. Polarity Measurement for Ionic Liquids Containing Dissociable Protons. Chemistry Letters, Volume 33(11), pp. 1414–1415
Reichardt, C., 1994. Solvatochromic Dyes as Solvent Polarity Indicators. Chemical Reviews, Volume 94(8), pp. 2319–2358
Rodrigues, C.E.C., Onoyama, M.M., Meirelles, A.J.A., 2006. Optimization of the Rice Bran Oil Deacidification Process by Liquid-liquid Extraction. Journal of Food Engineering, Volume 73, pp. 370–378
Rodrigues, C.E.C., Peixoto, E.C.D., Meirelles, A.J.A., 2007. Phase Equilibrium for Systems Composed by Refined Soybean Oil + Commercial Linoleic Acid + Ethanol + Water at 323.2 K. Fluid Phase Equilibria, Volume 261, pp. 122–128
Zahrina, I., Nasikin, M., Krisanti, E., Mulia, K., 2018. Deacidification of Palm Oil using Betaine Monohydrate-based Natural Deep Eutectic Solvents. Food Chemistry, Volume 240, pp. 490–495
Zhang, Q., Vigier, K.D.O., Royer, S., Je`rome, F., 2012. Deep Eutectic Solvents: Syntheses. Properties and Applications. Chemical Society Reviews, Volume 21, pp. 7108–7146