Optimization and kinetic modeling of esterification of the oil obtained from waste plum stones as a pretreatment step in biodiesel production

Continuous double-step acid catalyzed esterification production of sludge palm oil using 3D-printed rotational hydrodynamic cavitation reactor

Sludge palm oil (SPO) with high free fatty acid (FFA) content was processed using a continuous and double-step esterification production process in a rotor-stator-type hydrodynamic cavitation reactor. Three-dimensional printed rotor was made of plastic filament and acted as a major element in minimizing the FFA content in SPO. To evaluate the reduced level of FFAs using both methods, five independent factors were varied: methanol content, sulphuric acid content (H2SO4), hole diameter, hole depth, and rotor speed. The first-step conditions for the esterification process included 60.8 vol% methanol content, 7.2 vol% H2SO4 content, 5.0 mm diameter of the hole, 6.1 mm depth of the hole, and 3000 rpm speed of the rotor. The initial free fatty acid content decreased from 89.16 wt% to 35.00 wt% by the predictive model, while 36.69 wt% FFA level and 94.4 vol% washed first-esterified oil yield were obtained from an actual experiment. In the second-step, 1.0 wt% FFA was achieved under the following conditions: 44.5 vol% methanol content, 3.0 vol% H2SO4 content, 4.6 mm hole diameter, 5.8 mm hole depth, and 3000 rpm rotor speed. The actual experiment produced 0.94 wt% FFA content and 93.9 vol% washed second-esterified oil yield. The entire process required an average electricity of 0.137 kWh/L to reduce the FFA level in the SPO below 1 wt%.

New Type of Tannins Identified from the Seeds of Cornus officinalis Sieb. et Zucc. by HPLC-ESI-MS/MS

There is a lack of information on the compound profile of Cornus officinalis Sieb. et Zucc. seeds. This greatly affects their optimal utilization. In our preliminary study, we found that the extract of the seeds displayed a strong positive reaction to the FeCl₃ solution, indicating the presence of polyphenols. However, to date, only nine polyphenols have been isolated. In this study, HPLC-ESI-MS/MS was employed to fully reveal the polyphenol profile of the seed extracts. A total of 90 polyphenols were identified. They were classified into nine brevifolincarboxyl tannins and their derivatives, 34 ellagitannins, 21 gallotannins, and 26 phenolic acids and their derivatives. Most of these were first identified from the seeds of C. officinalis. More importantly, five new types of tannins were reported for the first time: brevifolincarboxyl-trigalloyl-hexoside, digalloyl-dehydrohexahydroxydiphenoyl (DHHDP)-hexdside, galloyl-DHHDP-hexoside, DHHDP-hexahydroxydiphenoyl(HHDP)-galloyl-gluconic acid, and peroxide product of DHHDP-trigalloylhexoside. Moreover, the total phenolic content was as high as 79,157 ± 563 mg gallic acid equivalent per 100 g in the seeds extract. The results of this study not only enrich the structure database of tannins, but also provide invaluable aid to its further utilization in industries.

Synergistic effect of microwave heating and hydrothermal treatment on cyanogenic glycosides and bioactive compounds of plum (Prunus domestica L.) kernels: An analytical approach

The effects of microwave heating (450 W for 6 min), hydrothermal treatment (6, 9, and 12 h at 45 °C) and their combination on compositional characteristics, cyanogenic glycosides, color, and bioactive compounds of plum kernels have been studied. The conditions examined caused a significant reduction of 37.81, 72.17, 84.41, 91.24 and 98.02% in cyanogenic glycosides of differently treated plum kernels. Total phenolic and total flavonoid compounds of plum kernels showed hydrothermal time-dependent duration decline. The larger shifts in FT-IR spectra near 1157 cm-¹ provided valuable insights on the reduction of cyanogenic glycosides during combined treatments. The variation of color attributes (L*, a*, b*), during combined treatments indicates a more reddish tonality of plum kernel samples. The combined effect of hydrothermal (12 h at 45 °C) and microwave heating (450 W for 6 min) proved to be an effective tool for neutralizing the toxic effect of cyanogenic glycosides, opening up possibilities for its use in food industries.

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Hydrothermal and microwave treatments were applied to detoxify plum kernels.

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The treatments caused highest reduction of 98.02% in cyanogenic glycosides.

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Combined treatments neutralized the toxic effect of cyanogenic glycosides.

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FT-IR spectra provided valuable insights on the reduction of cyanogenic glycosides.

The production of biodiesel from plum waste oil using nano-structured catalyst loaded into supports

The present study was undertaken with aims to produced catalyst loaded on low-cost clay supports and to utilize plum waste seed oil for the production of biodiesel. For this purpose, Bentonite-potassium ferricyanide, White pocha-potassium ferricyanide, Granite-potassium ferricyanide, Sindh clay-potassium ferricyanide, and Kolten-potassium ferricyanide composites were prepared. Transesterification of plum oil under the different conditions of reactions like catalysts concentrations (0.15, 0.3 and 0.6 g), temperature (50, 60, 70 and 80 °C), reaction time (2, 4 and 6 h) and oil to methanol ratio (1:10) was conducted. The maximum biodiesel yield was recorded for Bentonite-potassium ferricyanide composite. This composite was subjected to calcination process to produce Calcinized bentonite-potassium ferricyanide composite and a further improvement in biodiesel amount was recorded. The fuel quality parameters of all biodiesel samples were in standard range. Gas chromatographic mass spectrometric analysis confirmed the presence of oleic and linoleic acids in the plum seed oil. The characterization of composite was done using FTIR, SEM and EDX. Two infrared bands are observed in the spectrum from 1650 to 1630 cm-1 indicates that the composite materials contained highly hydrogen bonded water. The presence of surface hydroxyls groups can also be confirmed from FTIR data. SEM image clearly show the presence of nano-rods on the surface of Granite-potassium ferricyanide and Kolten-potassium ferricyanide composites. Another interesting observation that can be recorded from SEM images is the changes in surface characteristic of Bentonite-potassium ferricyanide composite after calcination (at 750 °C, 1 atm for 4 h). Calcinized bentonite-potassium ferricyanide composite found to contain more nano rod like structures at its surface as compared to Bentonite-potassium ferricyanide composite which contained spherical particles. EDX data of Bentonite-potassium ferricyanide composite and Calcinized bentonite-potassium ferricyanide composite show that after calcination carbon and oxygen was reduced. The other lost volatile compounds after calcination were of Na, Mg, Al, Si, and S. The XRD spectrum of pure bentonite showed the average crystal size of 24.46 nm and calcinized bentonite of 25.59 nm. The average crystal size of bentonite and potassium ferricyanide composite and its calcinized form was around 33.76 nm and 41.05 nm, respectively.

Esterification catalyzed by an efficient solid acid synthesized from PTSA and UiO-66(Zr) for biodiesel production

p-Toluenesulfonic acid (PTSA) is a typical homogeneous acid for biodiesel production. Due to the shortcomings of high deliquescence and non-recyclability, it is necessary to synthesize a recyclable solid acid. For the sake of this, UiO-66(Zr) is used to support PTSA through defect coordination, and four different preparation routes are compared. The obtained catalyst (UiO-G) is characterized with thermogravimetry analysis (TG), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), pyridine FTIR spectroscopy (py-FTIR), nitrogen adsorption-desorption, and base titration. In addition, the effects of esterification parameters on conversion are investigated to obtain the optimal conditions. To further verify the high catalytic activity of UiO-G, the kinetic model of solid-liquid-liquid esterification is established, in which the kinetic parameters of activation energy, reaction order, and exponential factor are calculated. Results indicate the PTSA is successfully inserted in UiO-66(Zr) without destroying its original structure. With that, the maximum conversion of oleic acid to biodiesel of 91.3% is achieved with a molar ratio of methanol/oleic acid of 12 and a catalyst amount of 8 wt% at 70 °C for 2 h. Moreover, UiO-G could remarkably reduce the activation energy, where the activation energy is 28.61 kJ mol-1, the average reaction order is 1.51, and the pre-exponential factor is 29.11 min-1.

Transesterification of Sunflower Oil over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study

The statistical experimental design (DoE) and optimization (Response Surface Methodology combined with Box-Behnken design) of sunflower oil transesterification catalyzed by waste chicken eggshell-based catalyst were conducted in a custom-made microreactor at 60 °C. The catalyst was synthesized by the hydration-dehydration method and subsequent calcination at 600 °C. Comprehensive characterization of the obtained catalyst was conducted using: X-ray powder diffractometry (XRD), X-ray fluorescence (XRF), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), N₂ physisorption, and Hg-porosimetry. Structural, morphological, and textural results showed that the obtained catalyst exhibited high porosity and regular dispersity of plate-like CaO as an active species. The obtained optimal residence time, catalyst concentration, and methanol/oil volume ratio for the continuous reaction in microreactor were 10 min, 0.1 g g^-1, and 3:1, respectively. The analysis of variance (ANOVA) showed that the obtained reduced quadratic model was adequate for experimental results fitting. The reaction in the microreactor was significantly intensified compared to a conventional batch reactor, as seen through the fatty acid methyl esters (FAMEs) content after 10 min, which was 51.2% and 18.6%, respectively.

Chemical Composition and in vitro Anti-inflammatory Activity of Wheat Germ Oil Depending on the Extraction Procedure

This study aimed to examine the chemical composition of wheat germ oil extracted by three different methods, and to evaluate its inhibitory effect on the cyclooxygenase and proteinase activities. The results showed that the contents of policosanols, tocopherols and phytosterols were affected by the extraction procedure. However, the fatty acid composition of the different oil extracts was nearly the same. Among the tested oils samples, cold pressed oil exhibited the strongest inhibitory activity against proteinase (93.4%, IC₅₀ =195.7 µg/mL) and cyclooxygenase 1 (80.5%, IC₅₀ =58.6 µg/mL). Furthermore, the cold pressed oil had the highest content of octacosanol, β-sitosterol and α-linolenic acid, suggesting that those bioactive compounds could be essential for the potent ani-cyclooxygenase activity. The present data revealed that wheat germ oil contained cyclooxygenase and trypsin inhibitors, which are the promising therapeutic target for the treatment of various inflammatory diseases. Thus, wheat germ oil might be used to develop functional foods and pharmaceutic products for the human health.

Cornus mas L. Stones: A Valuable By-Product as an Ellagitannin Source with High Antioxidant Potential

The stone of Cornus mas L. remains the least known morphological part of this plant, whereas the fruit is appreciated for both consumption purposes and biological activity. The stone is considered to be a byproduct of fruit processing and very little is known about its phytochemical composition and biological properties. In this study, the complete qualitative determination of hydrolyzable tannins, their quantitative analysis, total polyphenolic content, and antioxidant properties of the stone of C. mas are presented for the first time. The 37 identified compounds included the following: various gallotannins (11), monomeric ellagitannins (7), dimeric ellagitannins (10), and trimeric ellagitannins (7). The presence of free gallic acid and ellagic acid was also reported. Our results demonstrate that C. mas stone is a source of various bioactive hydrolyzable tannins and shows high antioxidant activity which could allow potential utilization of this raw material for recovery of valuable pharmaceutical or nutraceutical substances. The principal novelty of our findings is that hydrolyzable tannins, unlike other polyphenols, have been earlier omitted in the evaluation of the biological activities of C. mas. Additionally, the potential recovery of these bioactive chemicals from the byproduct is in line with the ideas of green chemistry and sustainable production.

The Utilization of Plum Stones for Pellet Production and Investigation of Post-Combustion Flue Gas Emissions

Agri-food waste is generated at various food cycle stages and is considered to be a valuable feedstock in energy systems and chemical syntheses. This research identifies the potential and suitability of a representative agri-food waste sample (i.e., plum stones) as a solid fuel. Ground plum stones containing 10, 15, and 20 wt.% of rye bran were subjected to pelletization. The pelletizer was operated at 170, 220, and 270 rpm, and its power demand for the mixture containing 20 wt.% of rye bran was 1.81, 1.89, and 2.21 kW, respectively. Such pellets had the highest quality in terms of their density (814.6 kg·m−3), kinetic durability (87.8%), lower heating value (20.04 MJ·kg−1), and elemental composition (C: 54.1 wt.%; H: 6.4 wt.%; N: 0.73 wt.%; S: 0.103 wt.%; Cl: 0.002 wt.%; O: 38.2 wt.%). Whole plum stones and pellets were subjected to combustion in a 25 kW retort grate boiler in order to determine the changes in the concentrations of NO, SO2, CO, CO2, HCl, and O2 in the post-combustion flue gas. Collected results indicate that plum stone–rye bran pellets can serve as effective substitutes for wood pellets in prosumer installations, meeting the Ecodesign Directive requirements for CO and NO.

Data on the derived mesoporous based catalyst for the synthesized of fatty acid methyl ester (FAME) from ternary oil blend: An optimization approach

This work presents datasets on fatty acid methyl ester (FAME) synthesized from the ternary blend of Cucurbita pepo-chrysophyllum albidum -papaya mix oils via methanolysis of mesoporous CaO heterogeneous catalyst derived from the mixture of Citrullus lanatus and Musa acuminate peels. The oils were extracted from the milled powdered using the solvent extraction method. Ternary oil mixed ratio of 33:33:34 with low acid value and density was achieved using simplex lattice design software. Characterization of the mixed calcined catalyst powder (MCCP) at 700 °C for 4 h was carried out using scanning electron microscopy (SEM), energy dispersive spectroscope (EDS), X-ray diffraction analysis (XRD), and BET analysis. The thermal decomposition of mixed calcined catalyst powder (MCCP) produced 78.74% CaO with a strong basic site of 143 (μmole.g⁻¹). Fatty acid methyl ester (FAME) was synthesized through the based catalyst transesterification of a derived catalyst by considering four variables data (reaction time, reaction temperature, catalyst amount and methanol/oil molar ratio) using response surface methodology (RSM). The maximum experimental FAME data of 94.29 (wt. %) was achieved at run 16, but the central composite design (CCD) software predicted value of 98.00 (wt. %) at a reaction time of 70 min, reaction temperature of 80 °C, catalyst amount of 5.0 (wt.) and methanol to oil molar ratio (MeOH/OMR) of 6.97, at the desirability of 97.90%. This was validated in triplicate, and the average FAME data obtained was 93.45 (wt. %). The produced FAME properties dataset meets the standard recommended value of ASTM and EN14214.

Spectroscopy approach to methanol detection in waste fat methyl esters

Second-generation biodiesel manufactured from waste cooking oils (WCO) and inedible animal fats (AF) are one of the alternatives to the first generation (1G) vegetable oil-based biodiesel. In this study, a quality control method is proposed to evaluate methanol content in waste fat methyl esters and is based on near infrared spectroscopy (NIR) combined with multivariate analysis. More specifically, calibration models are constructed using partial least squares regression (PLS) for the prediction of methanol content in rapeseed oil methyl ester (ROME), waste cooking oil methyl ester (WCOME), chicken fat methyl ester (CFME) and pork fat methyl ester (PFME) by Vis-NIR spectrometer. The calibration models are based on the absorbance spectra and computed data from five wavelength regions of 400-2170 nm, 780-2170 nm, 1400-2170 nm, 1400-1600 nm and 1970-2170 nm. For the cases with the highest prediction ability obtained in this study, the coefficient of determination of the model's goodness-of-fit for methanol concentrations range 0-5% (v/v) was R² > 0.990, and for concentrations 0-1% (v/v) was R² > 0.994, indicating the spectroscopic approach effectiveness in methanol content detection relevant to the biofuel quality assessment. A pseudo-univariate limits of detection (LOD_pu) and quantification (LOQ_pu) as well as ratio of performance to deviation (RPD) were used to confirm the validity and to evaluate the practical applicability of developed models. In addition, the obtained results indicate the possibility of developing a transmission sensor for online monitoring of the production process and the quality of biofuel.

Improving the lipid recovery from wet oleaginous microorganisms using different pretreatment techniques

Lipid extraction directly from the wet oleaginous microorganisms for biodiesel production is preferred as it reduces the energy input for traditional processes which require extensive drying of the biomass prior to the extraction. The high water content (≥80% on cell dry weight) in the wet biomass hinders the extraction efficiency due to the mass transfer limitation. This limitation can be overcome by pretreating wet biomass prior to the lipid extraction using pressurized gas that can be used alone or combined with other pretreatments to disrupt the cell wall. In this review, an extensive discussion on different pretreatments and the subsequent lipid extraction using these pretreatments is presented. Furthermore, a detailed account of the cell disruption using pressurized gas (e.g., CO₂) treatment for microbial cell lysing is also presented. Finally, a new technique on lipid extraction directly from wet biomass using the combination of pressurized CO₂ and microwave pretreatment is proposed.

Cosmetic potentials of Prunus domestica L. leaves

BACKGROUND

The current study presents new insight on the phytochemical content and biological activities of five Prunus domestica L. varieties ('Quetsche blanche de Létricourt', 'Mirabelle de Nancy', 'Perdrigon violet', 'Mirabelle de Provence', 'Reine-claude dorée').

RESULTS

The plum leaves were found to possess promising anti-aging activities by their capacity to inhibit 1,1-diphenyl-2-picrylhydrazyl (DPPH), elastase, hyaluronidase and lipoxygenase. After solid phase extraction (SPE), chlorogenic acid, rutin, quercetin and their derivatives were putatively identified by high-performance liquid chromatography coupled with tandem mass spectrometry using an electrospray ionization source (HPLC/ESI-MS/MS).

CONCLUSION

The plum leaf, a by-product, provides an interesting valuable resource for use as a natural cosmetic product or as a food supplement. © 2017 Society of Chemical Industry.

Enhanced esterification of oleic acid and methanol by deep eutectic solvent assisted Amberlyst heterogeneous catalyst

In present study, esterification of oleic acid with methanol using deep eutectic solvent (DES) assisted Amberlyst heterogeneous catalyst was investigated to produce biodiesel. Results showed that esterification efficiency was enhanced by the DES. The combined effect of DES on Amberlyst BD20 (BD20) is better than Amberlyst 15 (A-15) due to different structure. The optimal reaction conditions were 12:1M ratio of methanol to oleic acid, 20%(wt/wt) catalyst (BD20-DES (2:8) and A-15-DES (8:2)) at 85°C for 100min with agitating at 200rpm. The mechanism involved in catalysis and their capacity to reuse were studied. We proposed, Choline chloride-glycerol (Chcl-gly) DES could enhance the Amberlyst function due to the hydrogen bond effect on both DES and water. BD20 has fewer pores than A-15, have desirable performance in decreasing the inhibition the water during esterification of high FFA content and provide better performance in reuse.