Free Fatty Acids In Oil Research Articles

Comprehensive near infrared study of Jatropha oil esterification with ethanol for biodiesel production

This work presents a comprehensive near infrared study for in-line monitoring of the esterification reaction of high acid oils, such as Jatropha curcas oil, using ethanol. Parallel reactions involved in the process were carried out to select a spectral region that characterizes the evolution of the esterification reaction. Using absorbance intensities at 5176cm−1, the conversion and kinetic behaviors of the esterification reaction were estimated. This method was applied to evaluate the influence of temperature and catalyst concentration on the estimates of initial reaction rate and ester conversion as responses to a 22 factorial experimental design. Employment of an alcohol/oil ratio of 16:1, catalyst concentration of 1.5% w/w, and temperatures at 65°C or 75°C, made it possible to reduce the initial acidity from 18% to 1.3% w/w, which is suitable for transesterification of high free fatty acid oils for biodiesel production. Using the proposed analytical method in the esterification reaction of raw materials with high free fatty acid content for biodiesel makes the monitoring process inexpensive, fast, simple, and practical.

Oxidation stability of biodiesel derived from high free fatty acid feedstock

ABSTRACTAt present, with fluctuating feedstock prices, the biodiesel manufacturing industries are facing some downfall. High free fatty acid (FFA) non-edible oil, which is a byproduct of vegetable oil refineries, is available at low price and in considerable quantities at vegetable oil refinery sites. This high FFA oil can be utilized as a potential low cost feedstock for biodiesel production. In the present work, high FFA (51.6%) oil was synthesized into biodiesel by a two-step process. Except oxidation stability, other fuel properties of the produced biodiesel were found to be comparable with that of biodiesel specifications. Oxidation stability was found to be only 2.1 h at 110°C as determined by the Rancimat apparatus.In order to study and further improve the oxidation stability, the biodiesel (B100) was dosed with a suitable antioxidant (pyrogallol) and stored for 6 months. The acid value, peroxide value, and kinematic viscosity which are closely associated with oxidation behavior were studied. It was found that biodiesel dosed with an antioxidant showed the least increase in the acid value, peroxide value, and kinematic viscosity. Also, induction period was improved and found to be within the American Society for Testing and Materials limit . Thus, the high FFA oil-based biodiesel with a suitable antioxidant can be used as a potential feedstock to resolve the issue of the high cost of biodiesel production.

The epoxidation of canola oil and its derivatives

This work explores the epoxidation and subsequent acid catalyzed epoxy ring opening kinetics of canola oil (CanO), canola oil fatty acid methyl esters (CanFAME) and canola oil free fatty acids (CanFFA).

Study on the Effect of Operational Parameters on Conversion of Free Fatty Acids into Esters using Thin Layer Chromatography

Nowadays the fossil fuels are becoming outmoded by the renewable and biological fuels. The biofuels are categorised as biodiesel, biogas and producer gas. The biodiesel is produced from edible, non-edible oils, used cooking oils and animal fats. Yield of biodiesel from these feedstocks depends on the quality of oils such as free fatty acid (FFA) and moisture content. In this study, a non-edible oil feedstock, Jatropha curcas oil (8.81% oleic acid) was chosen for the biodiesel production with the aid of an acid and base catalyst. In the acid treatment, the high FFA oil was treated using sulphuric acid (2%) at 50°C for 1 h. This product mixture was separated into layers by gravity. The lower part of the mixture was known as pretreated oil, another layer was unknown component, and it was identified using thin layer chromatographic technique.

Quantification of Nonanal and Oleic Acid Formed During the Ozonolysis of Vegetable Oil Free Fatty Acids or Fatty Acid Methyl Esters

AbstractThe ozonolysis of unsaturated lipids is a process that has been used to generate aldehydes, acids, alcohols, and other biobased chemical intermediates. Reported here is a method that can be used to measure the formation of nonanal and oleic acid during the ozonolysis of unsaturated vegetable oil fatty acids or their methyl esters to indicate the extent of the ozonolysis reaction. Derivatization was performed using boron trifluoride in methanol solution to transform nonanal and oleic acid into nonanal dimethyl acetal and oleic acid methyl ester, respectively. Undecanal and 10‐heptadecenoic acid were used as internal standards and separation was performed using gas chromatography coupled with a flame ionization detector. The method was validated by performing a standard addition procedure in which nonanal or oleic acid standards were spiked into samples collected during the ozonolysis of oleic acid or canola oil fatty acid methyl ester (FAME). Linear regression results indicated that the measured nonanal and oleic acid are in good agreement with the actual amounts of nonanal and oleic acid added to the sample with at least 98 % recovery. The application of the method was demonstrated by the successful measurement of nonanal and oleic acid formed throughout the ozonolysis process for high oleic canola oil FAME.

Quantitative analysis of acidity level in virgin coconut oils by Fourier transform infrared spectroscopy and chemometrics

The quality of virgin coconut oil (VCO), together with its health functionalities, is directly related to its freshness and to the levels of free fatty acids (FFA). Thus, the goal of this work was to develop a quantitative model based on partial least squares regression (PLSR) to predict FFA levels (%) in VCO. A total of 72 Brazilian commercial samples classified in accordance to their shelf life was analyzed. FFA levels ranged from 0.3 to 2.3%. FTIR (Fourier transform infrared spectroscopy) spectra were recorded within a range of 3100 to 680 cm−1 and submitted to mathematical preprocessing. Quantitative models were developed by partial least squares regression (PLSR). Excellent predictive results were obtained, indicating that the FFA levels in VCO could be accurately quantified by FTIR. The correlation coefficient (R) and the root mean squared error of prediction (RMSEP) were, respectively, as high as 0.994 and as low as 0.07.Practical applications: According to international standards, acid‐base titration is the reference method for the determination of FFA in oils. This method is laborious and time‐consuming, uses toxic and flammable solvents and it is susceptible to error when detecting the color change of the indicator. Some of the advantages of FTIR over the official acid‐base titration method are the short time and simplicity of analysis. Besides that, it is non‐destructive and it does not require hazardous solvents and reagents. The results shown in this study indicate that FTIR spectroscopy and chemometrics can be successfully applied to the quantitative evaluation of FFA in VCO.The quality of virgin coconut oil (VCO), together with its health functionalities, is directly related to its freshness and to the levels of free fatty acids (FFA). Acid‐base titration is the reference method for the determination of FFA in oils. This method is laborious and time‐consuming, uses toxic and flammable solvents and it is susceptible to error when detecting the color change of the indicator. FTIR is a rapid, non‐destructive, and accurate technique that could overcome some of the drawbacks of titration methodologies and could be easily implemented in routine quality control laboratories. The results shown in this study indicate that FTIR spectroscopy and chemometrics can be successfully applied to the quantitative evaluation of FFA in VCO.

Impact of colloidal structure of gastric digesta on in-vitro intestinal digestion of whey protein emulsion gels

Two whey protein emulsion gels containing 10 mM NaCl (soft gel) or 200 mM NaCl (hard gel) were formed and subjected to sequential digestion, including an in vitro gastric step followed by an in vitro intestinal step. The breakdown of gel particles, stability of oil droplets, microstructure and free fatty acid release during digestion were examined. The results showed that after 60 and 240 min gastric digestion the digesta of both gels had different physicochemical forms. The 60 min gastric digesta of both gels was mainly composed of gel particles ranging from ∼1 to ∼1000 μm. The 240 min gastric digesta of the soft gel mainly consisted of individual oil droplets and small gel particles (∼10 μm) while that of the hard gel mainly consisted of small gel particles (∼10 μm). During intestinal digestion, the breakup and coalescence of oil droplets occurred simultaneously for all gastric digesta. The remaining network structure of gel particles hindered their breakdown especially in the hard gel during intestinal digestion, which delayed lipid digestion significantly. Lipolytic products appeared to accumulate around oil droplet surfaces. Needle-shaped crystals that may be composed of free fatty acids were also found during intestinal digestion.

Evaluation of the use of treated municipal waste water on the yield, oil quality, free fatty acids’ profile and nutrient levels in olive trees cv Koroneiki, in Greece

Tertiary reclaimed municipal wastewater was used in order to assess its effectiveness in irrigating olive trees cv Koroneiki against fresh water (FW), for two consecutive cultivating periods. A total of 140 olive trees were used and olive production, oil quality, oil free fatty acid profile and olive nutrition were assessed. The treated municipal wastewater (TMW) used was characterized by relatively low electrical conductivity values, still higher than the FW and higher NH4, Cl, K, Na, Fe, B, Al and Mn concentration than FW. The application of TMW slightly increased fruit production during the year of high tree yield (15.92kg fruit per tree versus 12.73kg per tree under FW irrigation) as well as the oil content, during the year of low yield (18.21% versus 16.43% under FW irrigation). It did not have any significant effect on the oil quality characteristics, such as free acidity, K270, K232, peroxide value and Delta K index. The irrigation treatment did not have any significant effect on the free fatty acid profile of the oil. Oleic acid was the dominant free fatty acid in the oil (ranging from 77.7 to 78.6%), followed by palmitic (10.6–11.1%), linoleic (5.5–5.8%) and stearic acid (2.5–2.8%), with their concentration falling within the range of the values for characterizing it as “Extra virgin” olive oil. The levels of K, Ca, Mg, Mn, Fe and Zn in the leaves increased with the application of TMW compared to FW, while the continuous use of TMW for two years led to a significant increase of P, Mg, Fe, Mn and Zn levels. The use of TMW under the experimental conditions described in the present study could be a valuable and profitable alternative to the use of FW in short term, by improving tree nutritional condition and enhancing oil production of superior quality.

Lipase-catalyzed biodiesel production and quality with Jatropha curcas oil: exploring its potential for Central America.

BackgroundExtensive native Jatropha curcas L. (Jatropha) crop areas have been planted in Central America marginal lands since 2008 as a non-edible prospective feedstock alternative to high-value, edible palm oil. Jatropha biodiesel is currently exclusively produced in the region at commercial scale utilizing alkaline catalysts. Recently, a free, soluble Thermomyces lanuginosus (TL) 1,3 specific lipase has shown promise as biocatalyst, reportedly yielding up to 96 % ASTM D6751 compliant biodiesel after 24 h transesterification of soybean, canola oils and other feedstocks. Biodiesel conversion rate and quality of enzymatically catalyzed transesterification of Jatropha oil was evaluated. Two lipases: free, soluble TL and immobilized Candida antarctica (CA) catalyzed methanolic transesterification of crude Jatropha and refined palm oil.ResultsJatropha yields were similar to palm biodiesel with NaOH as catalyst. After 24 h transesterification, Jatropha (81 %) and palm oil (86 %) biodiesel yields with TL as catalyst were significantly higher than CA (<70 %) but inferior to NaOH (>90 %). Enzymatic catalysts (TL and CA) produced Jatropha biodiesel with optimum flow properties but did not complied with ASTM D6751 stability parameters (free fatty acid content and oil stability index).ConclusionsBiodiesel production with filtered, degummed, low FFA Jatropha oil using a free liquid lipase (TL) as catalyst showed higher yielding potential than immobilized CA lipase as substitute of RBD palm oil with alkaline catalyst. However, Jatropha enzymatic biodiesel yield and stability were inferior to alkaline catalyzed biodiesel and not in compliance with international quality standards. Lower quality due to incomplete alcoholysis and esterification, potential added costs due to need of more than 24 h to achieve comparable biodiesel yields and extra post-transesterification refining reactions are among the remaining drawbacks for the environmentally friendlier enzymatic catalysis of crude Jatropha oil to become an economically viable alternative to chemical catalysis.

Production and Characterization of Ethyl Ester from Crude Jatropha curcas Oil having High Free Fatty Acid Content

The two step process was carried out to produce biodiesel from crude Jatropha curcas oil. The pretreatment process was carried out to reduce the free fatty acid content by (≤2 %) acid catalyzed esterification. The optimum reaction conditions for esterification were reported to be 5 % H2SO4, 20 % ethanol and 1 h reaction time at temperature of 65 °C. The pretreatment process reduced the free fatty acid of oil from 7 to 1.85 %. In second process, alkali catalysed transesterification of pretreated oil was carried and the effects of the varying concentrations of KOH and ethanol: oil ratios on percent ester recovery were investigated. The optimum reaction conditions for transesterification were reported to be 3 % KOH (w/v of oil) and 30 % (v/v) ethanol: oil ratio and reaction time 2 h at 65 °C. The maximum percent recovery of ethyl ester was reported to be 60.33 %.

Re-esterification of high free fatty acid oils for biodiesel production

The high free fatty acids (FFA) in most of the non-edible oils hinders their direct application in the production of biodiesel by using the traditional homogeneous base transesterification. In this study, a low temperature re-esterification process has been applied to reduce the FFA in castor oil for base catalysed transesterification. The response surface methodology based on central composite design was used to model and optimize the re-esterification efficiency under three reaction variables: reaction time, temperature, and glycerol to oil mass ratio. The optimum conditions for the highest re-esterification efficiency of 99.01% were found to be temperature of 56°C, reaction time of 85 minutes, and 2.34 g/g glycerol to oil mass ratio. These conditions reduced the high FFA of crude castor oil from 6.50% to 0.06% which is below the 3% recommended for alkali catalysed transesterification. The re-esterified oil was then transesterified using homogeneous base transesterification, resulting into a conversion of 97.95%. Except for viscosity, most fuel properties of the produced biodiesel were found to be comparable to those of ASTM D6751 and EN 14214 standards.

Microwave Assisted Energy Efficient Biodiesel Production from Crude Pongamia pinnata (L.) Oil Using Homogeneous Catalyst

Abstract Microwave assisted biodiesel production from crude Pongamia pinnata oil using homogeneous base catalyst (KOH) was unsuccessful because of considerable soap formation. Therefore, a two step process of biodiesel production from high free fatty acid (FFA) oil was investigated. In first step, crude P. pinnata oil was acid catalyzed using H 2 SO 4 and acid value of oil was reduced to less than 4 mg KOH/g. Effect of sulfuric acid concentration, alcohol-oil molar ratio and microwave irradiation time on acid value of oil was studied. Result suggested that 1.5% H 2 SO 4 (w/w), 6：1 methanol oil molar ratio and 3 min microwave irradiation time was sufficient to reduce the acid value of oil from 12 and 22 mg KOH/g to 2.9 and 3.9 mg/KOH/g, respectively. Oil obtained after pretreatment was subsequently used for microwave assisted alkali catalyzed transesterification. A higher biodiesel yield (99.0%) was achieved by adopting two step processes. Microwave energy efficiency during alkali catalyzed transesterification was also investigated. The results suggested a significant energy saving because of reduced reaction time under microwave heating.Key Words: microwave, pongamia pinnata, biodiesel, acid value, energy efficiency

Physico-Chemical Properties of Biodiesel Produced from Neem Oil

Biodiesel is becoming prominent among the alternatives to conventional petro-diesel due to economic, environmental and social factors. The quality of biodiesel is influenced by the nature of feedstock and the production processes employed. High amounts of free fatty acids (FFA) in the feedstock are known to be detrimental to the quality of biodiesel. In addition, oils with compounds containing hydroxyl groups possess high viscosity due to hydrogen bonding. American Standards and Testing Materials, (ASTM D 6751) recommends FFA content of not more than 0.5% in biodiesel and a viscosity of less than 6 mm2/s. In this experiment the seed oils of 30 Neem (Azadirachta indica. A. juss) biotypes were screened and evaluated for their physico-chemical parameters for their potential in biodiesel. The properties of Neem biodiesel were compared with Bureau of Indian Standards (BIS) and the fuel properties of diesel. Results showed that high amounts of FFA in oils produced low quality biodiesel while neutralized oils with low amounts of FFA produced high quality biodiesel. The quality of biodiesel from jatropha and castor oils was improved greatly by neutralising the crude oils.

Physico-Chemical Properties of Biodiesel Produced from Neem Oil

Biodiesel is becoming prominent among the alternatives to conventional petro-diesel due to economic, environmental and social factors. The quality of biodiesel is influenced by the nature of feedstock and the production processes employed. High amounts of free fatty acids (FFA) in the feedstock are known to be detrimental to the quality of biodiesel. In addition, oils with compounds containing hydroxyl groups possess high viscosity due to hydrogen bonding. American Standards and Testing Materials, (ASTM D 6751) recommends FFA content of not more than 0.5% in biodiesel and a viscosity of less than 6 mm2/s. In this experiment the seed oils of 30 Neem (Azadirachta indica. A. juss) biotypes were screened and evaluated for their physico-chemical parameters for their potential in biodiesel. The properties of Neem biodiesel were compared with Bureau of Indian Standards (BIS) and the fuel properties of diesel. Results showed that high amounts of FFA in oils produced low quality biodiesel while neutralized oils with low amounts of FFA produced high quality biodiesel. The quality of biodiesel from jatropha and castor oils was improved greatly by neutralising the crude oils.

Biodiesel Production from Waste Coconut Oil in Coconut Milk Manufacturing

The purpose of this research was to develop a 3 step biodiesel production from waste coconut oil taken from a wastewater pond in a coconut milk manufacturing plant. Special attention was paid to optimizing the first step, acid catalyzed hydrolysis, to convert the waste coconut oil into high free fatty acid oil, 83.32 wt%. The first step was the acid hydrolysis, in order to produce high free fatty acid oil. The optimum condition in acid hydrolysis was 5 % by mass of hydrochloric acid, in order to produce high free fatty acid oil that could be used as raw material for biodiesel production. The second step was the acid esterification, in order to reduce the FFA and convert FFA to methyl ester. The reduction of the FFA from 83.32 % in high free fatty acid oil to less than 2 % required 3 % by mass of hydrochloric acid, a molar ratio of methanol to oil of 10: 1, and a reaction time of 60 min. The alkaline transesterification in the third step was used triglyceride at 1.0wt% of KOH for catalysis, a molar ratio of methanol to oil of 6:1, and a reaction time of 60 min. The waste coconut oil biodiesel was further evaluated by determining its fuel quality, and most of the properties were well within ASTM and EN standards.doi:10.14456/WJST.2015.24

Enrichment of Refined Olive Oil with Palmitic and Docosahexaenoic Acids to Produce a Human Milk Fat Analogue

AbstractRefined olive oil was enriched with palmitic acid (PA) and docosahexaenoic acid (DHA) via lipase‐catalyzed acidolysis reaction using Novozym 435 in hexane. The enrichment reaction was optimized by response surface methodology. Three independent variables, reaction time (12, 18, and 24 h), temperature (55, 60, and 65 °C), and substrate molar ratio (refined olive oil:DHA single cell oil free fatty acid:PA 1:1:6, 1:1:9, and 1:1:12) and three responses, total PA and DHA incorporation, and PA content at the sn‐2 position were investigated. Results showed that PA was incorporated into the triacylglycerols(TAGs) of refined olive oil at up to 55.79 mol % while incorporation of PA at the sn‐2 position and total DHA were found to be up to 33.63 and 3.54 mol %, respectively. Second‐order models were generated for each of the three responses. A Chi‐square test verified that the predicted values from the models were not significantly different from the observed ones. The prediction power of the models was further confirmed by a solvent‐free scale‐up reaction. The produced structured lipids have the potential to be used in infant formula.

Liquid Crystal-Based Sensors for Rapid Analysis of Fatty Acid Contamination in Biodiesel

Biodiesel is produced from various vegetable oils via a transesterification reaction. Emulsification of biodiesel during the transesterification reaction can occur, however, if free fatty acids are present in the feedstock oil. The emulsified product is not usable. Here we report a facile method using a liquid crystal (LC)-based sensing platform for detection of free fatty acids in oils at levels (1 wt%) relevant to biodiesel production. The approach involves the partitioning of fatty acid (doped into LC) to an aqueous-LC interface and an associated anchoring transition of the LC, leading to an optical read-out. Unlike other methods for detection of fatty acids (e.g, pH), this approach directly measures interfacial activity of fatty acids that underlies emulsion stability. We describe the influence of the molecular structures and concentrations of fatty acids, and the solution condition (pH), on fatty acid-triggered ordering transitions of LCs.

Utilization of oil extracted from spent coffee grounds for sustainable production of polyhydroxyalkanoates

Spent coffee grounds (SCG), an important waste product of the coffee industry, contain approximately 15wt% of coffee oil. The aim of this work was to investigate the utilization of oil extracted from SCG as a substrate for the production of poly(3-hydroxybutyrate) (PHB) by Cupriavidus necator H16. When compared to other waste/inexpensive oils, the utilization of coffee oil resulted in the highest biomass as well as PHB yields. Since the correlation of PHB yields and the acid value of oil indicated a positive effect of the presence of free fatty acids in oil on PHB production (correlation coefficient R (2) = 0.9058), superior properties of coffee oil can be probably attributed to the high content of free fatty acids which can be simply utilized by the bacteria culture. Employing the fed-batch mode of cultivation, the PHB yields, the PHB content in biomass, the volumetric productivity, and the Y P/S yield coefficient reached 49.4g/l, 89.1wt%, 1.33g/(lh), and 0.82g per g of oil, respectively. SCG are annually produced worldwide in extensive amounts and are disposed as solid waste. Hence, the utilization of coffee oil extracted from SCG is likely to improve significantly the economic aspects of PHB production. Moreover, since oil extraction decreased the calorific value of SCG by only about 9% (from 19.61 to 17.86MJ/kg), residual SCG after oil extraction can be used as fuel to at least partially cover heat and energy demands of fermentation, which should even improve the economic feasibility of the process.

Activity of Sulfated Aluminium-Tin Mixed Oxides for the Esterification of Free Fatty Acids in Crude Palm Oil

Large amounts of free fatty acids in oil used for the production of biodiesel cause the problems of soap formation and very low yield of biodiesel. To overcome these problems, free fatty acids must be esterified to their esters in the presence of an acid catalyst prior to alkaline-catalyzed transesterification. Sulfated metal oxides are an interesting group owing to their very high acidity. In this study, sulfated aluminium-tin mixed oxide (SO4 2−/Al2O3-SnO2) catalysts were synthesized and used for esterification of free fatty acids in crude palm oil for the first time. The SO4 2−/Al2O3-SnO2 catalysts were prepared from different Al precursors, calcination temperatures, and sulfate concentrations. Characterization of the catalysts included X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques, nitrogen adsorption, Fourier transform infrared spectroscopy (FTIR), and potentiometric titration. The results show that the SO4 2−/Al2O3-SnO2 catalyst has very strong acid sites. Different Al precursors lead to different activities of the SO4 2−/Al2O3-SnO2 catalysts. Al2(SO4)3 is the best precursor whereas Al(NO3)3 is the worst one to prepare the SO4 2−/Al2O3-SnO2 catalyst. The optimum calcination temperature is 450°C. The activity of the SO4 2−/Al2O3-SnO2 catalyst increases with sulfate concentration. Introducing Al2O3 to SO4 2−/SnO2 increases its stability during the reusability process. Therefore, SO4 2−/Al2O3-SnO2 is a better candidate than SO4 2−/SnO2 for catalyzing the esterification of free fatty acids in crude palm oil.

Feasibility of Using High-Intensity Ultrasound Assisted Biodiesel Production from Mixed Crude Palm Oil in Two-Step Process

Biodiesel from a high free fatty acid (FFA) mixed crude palm oil (MCPO) can be produced to high fatty acid methyl ester (FAME) conversion by a two-step process. The first process is an acid-catalyzed esterification to reduce FFA in oil followed by a base-catalyzed transesterification process to produce biodiesel from esterified oil. In this study, the transesterification of esterified oil with methanol in the presence of potassium hydroxide (KOH) was performed in a 1,000 W ultrasonic homogenizer at a low frequency of 18 kHz. The use of high-intensity ultrasound to accelerate the reaction, the high surface power density of 1.62 W.mm-2 and the volumetric acoustic energy of 20 W.mL-1 were fixed. The objective of this study was to determine the various parameters (methanol concentration, KOH concentration, and initial temperature of oil) to produce the FAME conversion. The results showed that over 98 wt.% of FAME could be achieved with 5 g KOH/liter of oil, 15 vol.% of methanol, the total residence time of 20 seconds, and temperature of 30 oC. Moreover, the glycerides were rapidly converted to the FAME within reaction time of 10 seconds when the base-catalyst of 10 g KOH/liter of oil, and 20 vol.% of methanol were used. Consequently, the use of high-intensity ultrasonic irradiation can minimize the chemical cost, electricity cost, and reaction time.