Deacidification Of Oil Research Articles

Use of Rhizomucor miehei fermented babassu cake (an agro-product residue) as efficient biocatalyst for macaúba acid oil deacidification in solvent-free medium: Transforming a non-edible crop product in a favourable biodiesel feedstock

Macaúba, a native South American palm, is used to recover degraded areas in important Brazilian biomes and presents a high oil productivity. Macaúba pulp oil is a sustainable alternative for biodiesel production. However, its high acidity represents a problem for its use. This paper shows an enzymatic process to reduce the acidity of macaúba pulp oil (9.5 wt% acidity) using a low-cost agro-industrial by-product to get a solid-state fermented solid with lipase activity from Rhizomucor miehei. Ethanol, methanol and glycerol were evaluated as acyl acceptors for the esterification of the free fatty acids (FFA) in the oil. Methanol was the best acyl acceptor, with 3.6 and 2.4 times higher deacidification rate than ethanol and glycerol, respectively, for reactions conducted with FFA to alcohol stoichiometric molar ratio. The alcohol stepwise addition strategy gave better results for all tested acyl acceptors. At the best reaction condition (methanol/FFA molar ratio of 6:1, methanol stepwise addition), the desired FFA esterification (acidity of 0.4 wt%, compatible with biodiesel plants requirements) was attained after only 2.5 h. This means the conversion of two no interesting crop products into valuable products.

Process optimization and modeling of Acer truncatum seed oil deacidification by molecular distillation

Acer truncatum seed oil (ATO) is a unique woody oil resource, but its high acid value resulting from traditional pressing methods falls short of meeting the necessary food standards. In this research, molecular distillation (MD) was employed for the deacidification of ATO and compared with conventional techniques such as alkali refining and solvent extraction. Predictive models for MD deacidification were established through single-factor experiments, orthogonal experimental design (OED), response surface methodology (RSM), and genetic algorithm - back propagation artificial neural network (GA-BP-ANN). Using RSM, a fitting model was obtained with R = 0.999 and Rpre = 0.990 through multiple linear regression. The constructed BP-ANN model (3-9-1) exhibited R = 0.998 and Rpre = 0.998, indicating slightly higher prediction accuracy. With GA-BP-ANN, the optimal process conditions are an evaporator temperature of 190 °C, condensation temperature of 40 °C, scraper speed of 324 rpm, yielding an acid value of refined ATO at 0.240 ± 0.001 mg g−1. Therefore, under appropriate conditions, the MD deacidification method can produce high-quality refined ATO. The developed orthogonal, RSM, and GA-BP-ANN models demonstrated excellent capabilities in optimizing and predicting the MD deacidification process, meeting even the strictest food regulations.

Magnetic polydopamine nanoparticles as stabilisers for enzyme-Pickering emulsions: Application in the interfacial catalytic reaction of olive oil

Solid particles are essential for stabilising Pickering emulsions and improving interfacial catalytic reactions. We constructed magnetic polydopamine nanoparticles to stabilise lipase-Pickering emulsions for olive oil deacidification. The results showed that the nanoparticles had a core-shell structure with an average particle size of 605.8 nm, a zeta potential of −39.3 mV and a contact angle of 55.9°, which effectively stabilised the emulsion. The particles were added to the lipase solution and sonicated to construct the emulsion system. The emulsion droplets were the smallest and most uniformly distributed under 400 W ultrasonic irradiation for 10 min. The lipase adsorbed on the oil-water interface and promoted the hydrolysis of olive oil. The released fatty acid content increased 1.7-fold compared with the non-emulsion. This study not only provides a new immobilisation method for the interfacial catalysis of lipase but also provides ideas for the high-value utilisation of high acid-value oil resources.

Cold-pressed camelina oil deacidification using short path molecular distillation: An optimization study and comparison with conventional techniques

In this research, the impact of short-path molecular distillation (SPMD), as a green and solventless method, in the deacidification of cold-pressed camelina oil (CPCO) was investigated. Physical refining of crude vegetable oils with high free fatty acids (FFA) content leads to healthier oils, preventing excessive oil loss and minimizing waste production. Using central composite design approach-based response surface methodology (RSM-CCD) analysis, optimized SPMD process parameters were determined and verified. The investigated factors were evaporation temperature (ET: 160–200 °C), feed flow rate (Q: 0.50–3.00 mL/min), and feed temperature (FT: 80–120 °C). Deacidification efficiency (DE) and distillate-to-feed mass ratio (D/F) were selected as the separation performance responses. In addition, to monitor the qualitative effect of the SPMD, peroxide value (PV) and total polar compounds (PC) were designated as the complementary responses. The optimized values for ET, Q, and FT could be considered to be 200 °C, 0.50 mL/min, and 100 °C, respectively. At the optimum operating conditions, DE, D/F, PV, and PC were determined as 63.27 %, 5.78 %, 24.5 meq/kg, and 11.4 wt%, respectively. The SPMD were compared with conventional fractional distillation (FD), steam stripping distillation (SSD), and alkali neutralization (AN). It was validated that SPMD could efficiently and sustainably deacidify the CPCO. Additionally, the effect of two successive SPMD treatments at the optimum conditions was also examined. By double deacidification, the DE, D/F, PV, and PC values were 74.34 %, 6.88 %, 27.6 meq/kg, and 16.0 wt%, respectively.

Optimization of operating conditions for lampante olive oil deacidification by short path molecular distillation: Waste valorization approach

Short path molecular distillation (SPMD) is an advanced distillation eco-friendly technique performed under high vacuum with vast applications in food processing, including vegetable oils physical refining. In this research, lampante olive oil, as a low-grade byproduct of olive oil producing companies, with high free fatty acids (FFA) content of 10.11 (wt % as oleic acid) was deacidified using SPMD. Optimization of SPMD was carried out using Box-Behnken response surface methodology (RSM-BB). Three important operating factors including evaporation temperature (150–200 °C), feed flow rate (0.50–3.00 mL/min), and feed temperature (50–100 °C) were selected to evaluate the SPMD process. At the best separation conditions of 195 °C, 0.5 mL/min, and 50 °C, the FFA content, deacidification efficiency (DE) and polar compounds (PC) were determined as 1.42 wt %, 85.95 % and 8.2 wt % respectively. Furthermore, SPMD efficiency was compared to some conventional methods including fractional distillation (FD), steam stripping distillation (SSD) and alkali neutralization (AN). In addition, the impact of FFA content on SPMD process was examined. It was concluded that SPMD could effectively and sustainably deacidify lampante olive oil to a reasonable extent and could facilitate the physical refining as a valorization process.

Tuning multi-purpose glycerol-based deep eutectic solvents for biocatalytic deacidification of high-acid rice bran oil: Kinetics, mechanism, and inhibition of side glycerolysis

Developing an effective deacidification process to utilize high-acid rice bran oil (HRBO) for the production of high-quality and value-added edible products remains challenging. In this study, we developed a novel, multi-purpose, and sustainable lipase-deacidification system for HRBO utilization in glycerol-based deep eutectic solvents (DESs), resulting in a 94.5% deacidification efficiency and simultaneously prevented the glycerolysis side reaction. Importantly, the enzymatic kinetics were investigated in comparison with choline chloride/glycerol DESs and the pure glycerol system. In addition, the underlying mechanism of inhibition accompanied by glycerolysis side reaction in the enzymatic-deacidification of HRBO was proved by molecular docking simulations. We believe our findings demonstrate the potential of glycerol-based DESs as a highly efficient, sustainable, and recyclable solution for the deacidification of edible oils.

Application of integrated molecular distillation-adsorption process for deacidification and recovery of vitamin E and carotenoids from palm oil

Palm oil is a natural source of phytonutrients such as vitamin E and carotenoids. However, these high-value compounds are lost during conventional refining. These phytonutrients can be separated and recovered from crude palm oil (CPO) through methods which prevents the degradation of these compounds. This study evaluated the integrated approach of molecular distillation and adsorption, with the aim of deacidifying and separating vitamin E and carotenoids from CPO, allowing their recovery. Wiped-film molecular distillation (WFMD) was used for deacidification and vitamin E enrichment, the best results were obtained at 200 °C and 21 mL/min. The distillate stream was enriched 937.8% in vitamin E, and the residue stream (named deacidified palm oil - DAPO), enriched in carotenoids, reached 0.1% free fatty acids (FFA). Integration with the adsorption process achieved a carotenoids removal of 79.4% from the DAPO stream. Moreover, the kinetic constant (k2) of adsorption increased by around 87% for DAPO, a result attributed to the absence of fat crystals on the adsorbent surface verified by scanning electron microscopy. Notably, the integrated process approach used is an innovative methodology for the vegetable oil industry presenting an alternative route that allows the preservation and recovery of phytonutrients, and the oil deacidification.

Exploring the potential of naturally-derived ionic liquids for sustainable vegetable oil deacidification

This work investigated two different approaches for vegetable oil deacidification using an ionic liquid (IL), composed of cholinium cation ([Ch]) and oleate anion ([OLE]), as a solvent to form oligomeric ILs (OILs) potentially, and reactive extraction to form multicomponent ILs (MILs) from different acids. The OIL approach (adding an excess acid into the IL through hydrogen bonding) removed oleic acid (∼80%) from a commercial vegetable soybean oil, previously acidified, possibly due to high intermolecular interactions. Through MIL approach, the FFA removal was up to 85%. In this case, the MIL formation occurred concomitant to deacidification as a driving force. Both strategies were evaluated in crude vegetable oil, and the high removal indexes were maintained. Concerning the oil loss, the MIL and OIL approaches result in a significantly lower oil loss (up to 5%) than conventional chemical processes (up to 50%). Finally, envisioning integrated processes, MIL was reused in a new deacidification process, achieving good results (removal of FFA up to 85%). Alternatively, reused MILs and OILs were employed in the β-carotene and astaxanthin recovery from P. rhodozyma wet biomass, indicating that the obtained IL-based systems could be further used as green solvents for other sustainable extraction processes.

Effect of alkaline microcrystalline cellulose deacidification on chemical composition, antioxidant activity and volatile compounds of camellia oil

The effect of alkaline microcrystalline cellulose (AMC) deacidification and alkali refining on the physicochemical properties, fatty acid profile, active phytochemicals, antioxidant capacity, and volatile flavor components of crude camellia oil (CO) were investigated comparatively. The results showed that the acid value of AMC deacidification camellia oil (ADO) was effectively decreased from 1.50 ± 0.00 mg KOH/g to 0.30 ± 0.01 mg KOH/g. AMC deacidification more effectively retained 60.22% of the polyphenols (12.34 ± 0.38 mg GAE/100g), 74.60% of α-tocopherol (2.82 ± 0.00 mg/kg) and 93.25% of β-Sitosterol (5.30 ± 0.05 mg/100g) in camellia oil compared to alkali refining and showed a stronger overall antioxidant capacity of the oil (P < 0.05). In addition, the volatile flavors of camellia oil were dominated by acids, aldehydes, and alcohols, and AMC deacidification better preserved the acidic flavors than alkali refining. Principal component analysis (PCA) revealed that ADO and CO were positively correlated with PC1 due to the highly in relation to the higher content of 9C, 11 TR-Conjugated linoleic acid and the stronger antioxidant capacity. Overall, AMC deacidification was moderate reaction conditions and zero wastewater production, making it a potentially effective alternative method in camellia oil deacidification.

Kinetics of reactive extraction of free fatty acids in jatropha oil with monoethanolamine in methanol: A key biodiesel pre-processing step

Unrefined vegetable oils and fats contain free fatty acids and they ought to be minimized for use in food and non-food applications. Traditional deacidification of vegetable oils and fats adopts alkali neutralization for the removal of free fatty acids. Here, a simple method for the removal of free fatty acids from jatropha oil by reactive extraction using monoethanolamine in methanol is proposed. Reactive extraction kinetic studies with initial free fatty acids concentration (0.1–0.5 kmol/m3) using monoethanolamine (0.4141–1.6568 kmol/m3) in methanol at 30 °C was performed and investigated. Parameters like distribution coefficient, equilibrium complexation constant for free fatty acids extraction were obtained to arrive at equilibrium and kinetic conclusions. Most importantly, the criteria for reaction regime was established through Hatta number. The study revealed that reactive extraction of free fatty acids using monoethanolamine in methanol falls under reaction regime 2. The study demonstrated that reactive extraction was highly successful in reduction of the free fatty acids in jatropha oil. Further biodiesel was prepared using the deacidified oil and the specifications obtained were well within the standard ASTM limits.

Deacidification of Acidic Oil Catalyzed by Sulfonated Mesoporous Silica for Biodiesel Production: Optimization, Kinetic, and Enhancement by Using Calcined Kaolin

Acidified oil is characterized as high acid value. Hence, deacidification is indispensable in biodiesel production from acidic oil. Heterogeneous catalysts have many advantages over homogeneous counterparts in deacidification of acidic oil. Therefore, in the present work, sulfonated mesoporous silica (SMS) was prepared and characterized, followed by the systematical investigation on the effect of reaction variables on the deacidification rate (DR). Furthermore, response surface methodology (RSM) was employed to optimize the reaction parameters. Results showed that the optimal studied reaction variables for the deacidification process were as follows: reaction temperature 65 °C, methanol to oleic acid ratio 35:1, catalyst loading of 2%, in which, deacidification rate of 97.78% could be achieved. DR of 62.52% could still be obtained after catalyst had been used for four consecutive cycles. Finally, significant enhancement of DR could be achieved by using calcined kaolin to assist the deacidification of acidified oil with high water content, indicating that there is great potential in deacidification of acidic oil catalyzed by SMS with the assistance of calcined kaolin for biodiesel production.

Membrane Assisted Edible Oil Deacidification

Although humans started using edible vegetable oils as a part of food, ages ago, there have been considerably lesser improvements in the way they are refined. Chemical and Physical Refining processes are surely the best in terms of the quality of the oil obtained, but they lead to neutral oil loss and higher energy consumption respectively, necessitating the urge to find processes with lower oil losses or energy required, yet giving similar quality oil. These drawbacks are majorly due to the deacidification step, which is a part of the whole refining process. To address this, many researchers and scientists have been working for decades and have found some good alternatives, which carry out decidification in a sustainable and greenway. This article focuses on one such solution i.e., Membrane Assisted Edible Oil Deacidification, which has the potential to be introduced as an alternative for the conventional refining methods.

Low-cost liquid lipase selective deacidification of corn oil with high triglyceride yield

In order to remove free fatty acids (FFA) in crude oil and improve edible oil quality, deacidification was often used in oil refining. In this work, several liquid enzymes were firstly screened for the selective deacidification of the degummed corn oil, and ethanol was used as a novel fatty acyl acceptor in solvent-free system, which showed a good selective deacidification efficiency and high triglyceride yield. Reaction conditions were optimized by response surface methodology as follows: 3 % enzyme dosage and 20:1 substrate ratio (alcohol/FFA) at 50 °C for 50 min. Under these conditions, the acid value, yield of neutral oil, and contents of sterol and vitamin E of corn oil were 0.31 ± 0.06 mgKOH/g, 94.0 ± 0.5 %, 1,012.9 ± 11.2 mg/100 g, and 1,320.0 ± 3.8 mg/kg, respectively. Meanwhile, thermodynamic and kinetic parameters were investigated. These results showed that this process was beneficial to selective deacidification, high yields of neutral oil and bioactive components in corn oil.

Deacidification of high-acid rice bran oil by the tandem continuous-flow enzymatic reactors

Rice bran oil (RBO) contains a variety of nutrients, but the high acid values largely hinder its processing into edible oil. Thus, the tandem continuous-flow reactors are proposed and developed for the enzymatic deacidification of RBO and simultaneous production of functional oils. The results indicate that the Candida antarctica lipase B (CALB) immobilized on the hydrophobic ordered mesoporous silicon (OMS-C18) increased 6.6 times of the catalytic activity and improved at least 20 ℃ of temperature tolerance compared to the commercial Novozym 435. The tandem continuous-flow enzymatic reactors removed 91.4% of free fatty acid and increased 9 and 12 times of phytosterol ester and diacylglycerol in RBO, respectively. Moreover, the retention rate of γ-oryzanol was at least 40% higher than that obtained by traditional alkali refining. This study provides an effective and sustainable method to continuously convert the low-value RBO into value-added products, which brings huge potential to cleaner industrial production.

Deep eutectic solvent (DES) assisted deacidification of acidic oil and retaining catalyst activity: Variables optimization and catalyst characterization

Deacidification is a critical step in alkali catalyzed transestrification of acidic oil for biodiesel production. In this work, optimization of the process variables and insights into the mechanisms of deep eutectic solvent (DES) assistance of deacidification of acidic oil catalyzed by Amberlyst 15 were investigated. Specifically, response surface methodology (RSM) and Box-Behnken Design (BBD) were employed to optimize the three process variables, namely temperature, catalysis loading, and molar ratio of methanol to oleic acid. Furthermore, the catalysts before and after used with and without DES assistance were characterized by FTIR and XRD in order to elucidate the chemical mechanisms involved in the process. Results showed that maximum deacidification rate (DR) of 98.02% was achieved in the deacidification process assisted by DES at the optimal process conditions (temperature 72.02ºC, catalyst loading 5.05 wt%, and methanol to oleic acid molar ratio 33.02), compared to 89.68% of the control (without DES assistance). Data analysis and verification results further confirmed the suitability of BBD and RSM methods in optimizing the process. More interestingly, dramatic higher catalytic activity (DR of 76.33% vs 64.16%) of Amberlyst 15 with DES assistance compared to that of the control after 4 cycles was observed. Finally, FTIR spectra confirmed that less water absorbed onto the surface of Amberlyst 15 with DES assistance was the major reason for higher DR and better catalyst reusability in comparison with the control.

Walnut oil deacidification by liquid–liquid extraction with aqueous ethanol in a singleand multistage crossflow process

Walnut oil deacidification by liquid–liquid extraction with aqueous ethanol in a singleand multistage crossflow process

Synthesis of lipase-hydrogel microspheres and their application in deacidification of high-acid rice bran oil

The main challenge of rice bran oil (RBO) as a highly nutritional edible oil is the high content of free fatty acids.

In search of sustainable alternatives for vegetable oils deacidification using oligomeric ionic liquid approach

Crude vegetable oils contain free fatty acids (FFAs) that can compromise the sensorial quality and oxidation stability, and thus, need to be removed by deacidification processes. However, conventional physical and chemical processes are related to neutral oil and nutraceutical loss, need of catalysts, and high energy consumption. The liquid-liquid extraction of these bioproducts using sustainable solvents, such as ionic liquids (ILs), seems to be interesting alternative over processes using bioethanol and organic solvents. In this work, the use of protic FA-based IL, such as diethanolammonium caprate ([H2EA][C10OO]) as solvent for deacidification of vegetable oils through the oligomeric IL approach was investigated. The liquid-liquid equilibria (LLE) data of systems containing [H2EA][C10OO], FA (palmitic, oleic and linoleic acids) and vegetable oil (palm olein, canola or soybean oils) were determined and modelled using NRTL model. IL presented good extraction efficiency of FFAs, presenting high distribution coefficient. Also, the NRTL model well described the LLE of such kind of systems. Moreover, solute-solvent affinity was evaluated by predictive COSMO model for a better comprehension of the results. Therefore, the results might indicate that protic FA-based ILs might have potential applicability as alternative solvents for deacidification of crude vegetable oils.

Efficient naphthenic acid extraction from high acidic oil using novel 1,5-diazabicyclo[4.3.0]non-5-ene based ionic liquids

In this work, the high acidic crude oil deacidification study was performed with novel 1-alkyl-1,5-diazabicyclo[4.3.0]non-5-ene (DBN) based ionic liquids (ILs). Firstly, we took advantage of the systematic COSMO-RS (Conductor-like Screening Model for Real Solvents) calculations to screen the possible ILs with good acid extraction performance from the combinations of 94 cations and 56 anions. Four 1-alkyl-1,5-diazabicyclo[4.3.0]non-5-enium imidazolide ([DBN-R][IM]) ILs with varying alkyl chains were eventually identified and synthesized successfully. Their deacidification performances were tested experimentally and different factors, including the alkyl chain length, ILs/oil mass ratio, temperature, and the initial total acid number (TAN) value of the simulated acidic oil, were also studied in detail. The experimental results showed that [DBN-R][IM] exhibited excellent performances on naphthenic acids (NAs) removal and [DBN-Et][IM] could achieve 93% of NAs removal employing the ILs/oil mass ratio of 0.06 at room temperature for the acidic oil with the TAN value of 3.28 mg KOH/g. COSMO-RS analyses were also used to elucidate the unusual effects of the alkyl chain length and temperature on the NAs extraction performances. Additionally, a two-step deacidification strategy was proposed aiming at realizing more efficient NAs extraction. Finally, density functional theory (DFT) calculations were carried out and the independent gradient model (IGM) analyses were applied to the IL-NAs system to get insight into the deacidification mechanism of the ILs.

Design of functional glycerol-based deep eutectic solvents as reaction media for enzymatic deacidification of high-acid rice bran oil

The effectiveness of deacidification technologies for high-acid rice bran oil (HRBO) are still one of the main challenges in the industrialization process of rice bran oil (RBO). A novel function of glycerol-based deep eutectic solvents (DESs) as an acyl acceptor in combination with lipases for enzymatic esterification of deacidification of HRBO was described in this study. The maximum deacidification efficiency of 92.38% was obtained under the optimized reaction conditions. Molecular docking simulation indicated that the minimum binding energy of Novozym 435 was lower than those of Lipozyme TL IM and Lipozyme RM IM, which might be one of the underlying mechanisms for its better performance. Additionally, γ-oryzanols, tocopherols and tocotrienols were retained in deacidified RBO. We are convinced that the reusability of biocatalyst and DESs systems provide an alternative strategy to design a facile, environmentally-friendliness DESs towards economic feasibility of applications and processes for oil-refined industries.