Regeneration and Reutilization of Oil-Laden Spent Bleaching Clay via in Situ Transesterification and Calcination

Landfill bound waste from the oil palm industry, spent bleaching clay (SBC) containing significant amounts of adsorbed crude palm oil (CPO) has the potential to be used for biodiesel production. In this study, SBC was subjected to ultrasound-aided in situ transesterification with a co-solvent to convert the oil into methyl esters (biodiesel). Optimized reaction conditions used were 5.4 wt% KOH, methanol to oil mass ratio of 5.9:1 and 1:1 mass ratio of co-solvent (petroleum ether or ethyl methyl ketone) to SBC. The remaining bleaching clay was calcined at 500 °C for 30 min and reutilized for bleaching. Absence of –CH absorption peaks in the FTIR and TGA-FTIR analysis of regenerated clays shows the regeneration efficiency of the method. In situ transesterification and heat regeneration helped to restore pores without adversely affecting the clay structure. The use of ethyl methyl ketone (EMK) as the co-solvent in the in situ transesterification process produced clay with better bleaching qualities.     

Method for analysis of 4-hydroxy-2-(E)-nonenal with solid-phase microextraction

A simple analytical method for 4-hydroxy-2-(E)-nonenal (HNE) using solid-phase microextraction (SPME) fiber was developed. HNE or the derivative of HNE formed by reaction with 2,4-dinitrophenylhydrazine (DNPH) was extracted from the sample solution by immersing the SPME fiber into the solution, and the amount of HNE was quantified by HPLC. The extraction conditions of HNE and HNE-DNPH were examined, using standard solutions, with respect to fiber coating, NaCl concentration, rate of stirring, adsorption temperature, and adsorption time. The recovery of HNE reached 80%, and the quantification limits of HNE and HNE-DNPH using standard compounds were 14.1 pmol/10 mL and 486.5 fmol/10 mL, respectively. This method can be applied to the detection of HNE in oxidized oil or samples of porcine liver.     

石墨碳纤维吸附基质的固相微萃取装置的研制及应用

研制了以石墨碳纤维吸附物质为代表，作为简单、耐用且性能优良的固相微萃取装置的吸附基质。该固相微萃取装置与ＧＣ－ＭＳ联用，吸附、分析烟用香料，结果表明它有很好的应用前景。     

Accurate determination of hexanal in beef bouillons by headspace solid‐phase microextraction gas‐chromatography mass‐spectrometry

Lipid oxidation has great impact on the quality of food products through flavor and taste deterioration, reduction in nutritive value, and potential toxicity of the oxidized food components. Flavor and taste deterioration can be easily perceived and it represents one of the major causes of consumer complaints in the food industry. The deterioration of sensory properties is due to the decomposition products of hydroperoxides that easily isomerize and degrade into volatile compounds. Volatile products are responsible for flavor and taste deterioration. In this study, we present the development of the solid‐phase microextraction gas chromatography‐mass spectrometry (SPME‐GC‐MS) technique to quantify low amounts (μg/g range) of secondary oxidation products, i.e. hexanal. The optimization of SPME parameters is a difficult task because of the possibility of further formation of volatile products during analysis. Different parameters such as type of fiber, exposure time of the fiber to the sample headspace and the optimal temperature of absorption have also been investigated. The complete validation of the method was achieved by the determination of linearity, limits of detection and quantification and repeatability. We demonstrated that the SPME method is a valuable tool for the quantification of low amounts of secondary oxidation products such as hexanal. Therefore, this technique can be used to detect early formation of volatiles.     

三羟基丙烷交联聚氨酯/有机硅固相微萃取涂层的研制和应用

通过三羟基丙烷交联聚氨酯/有机硅合成了有机硅/聚氨酯共聚物,将其涂渍于纤维丝上制成了固相微萃取(SPME)探头并安装于SPME装置上,与气相色谱联用测定了水中氯苯等芳香化合物。考察了该共聚物制成的萃取头热稳定性及使用寿命、影响萃取效率的因素。结果表明:有机硅/聚氨酯共聚物涂层具有使用寿命长(100次以上)、成本低、耐高温(270℃)等特点,对样品中氯苯等芳香化合物的萃取效果优于其它探头。本方法检出限低(0.05～0.5μg/L),重现性好(RSD4.8%～5.9%)。     

Restructuring the processes for furfural and xylose production from sugarcane bagasse in a biorefinery concept for ethanol production

This study consisted in restructuring the processes for furfural and xylose production from sugarcane bagasse in a biorefinery concept for the residues utilization on ethanol production.The dilute acid hydrolysis conditions for furfural or xylose production were firstly established on laboratory scale and then reproduced on a 10-L bench reactor fed with direct steam. The furfural production was maximum when using a 1.25% (w/w on dry fiber) H₂SO₄ solution at 175 °C during 40 min; whereas the xylose production attained the best results when using a 1% (w/v) H₂SO₄ solution in a solid/liquid ratio of 1/4 (g/mL), and the sugarcane bagasse impregnated with the acid solution during 24 h prior to the hydrolysis reaction. Enzymatic hydrolysis of the residual solid material obtained from furfural or xylose production was performed with yields of 17.4 and 9.3 g glucose/100 g initial raw material, respectively. Subsequently, ethanol was produced from the residual solid materials obtained from furfural and xylose production with yields of 87.4% and 89.3% respectively, based on the maximum theoretical value (0.51 g ethanol per g glucose in hydrolysate). Such results demonstrated the possibility of restructuring the processes for furfural or xylose production to obtain solid residues able to be used as substrate for ethanol production by fermentation.     

Comparison of differently coated SPME fibres applied for monitoring volatile substances in vegetable oils

Cereol Group Center of Expertise, Budapest, Hungary Solid‐phase microextraction (SPME) was developed to determine volatile substances from liquid, gas or even solid materials. This technique has been successfully applied for soil, waste water, blood and urine samples, but in spite of its advantages there are still few applications for vegetable oils. SPME is applicable to determine the aroma and other volatile compounds of the oil, which are characteristic to its origin and oxidative status. In this study the sensitivity and selectivity of some commercially available SPME adsorption materials (polydimethylsiloxane, divinylbenzene, carboxen) were compared. The diverse types of stationary phases were investigated by applying standard oils containing volatile substances from 9‐90 mg/kg concentrations. SPME fibre was placed into the headspace of an oil sample in a 30‐ml headspace vial thermostated at 80 °C for 45 min. The extracted volatile materials were desorbed from the fiber in the injection port of the gas chromatograph at 250 °C. Identification of the extracted compounds is based on pure standards and mass spectra. The reliability of the SPME sampling method was studied by parallel measurements. The 2‐cm long fibre coated with divinylbenzene (50 μm) and carboxen (30 μm) proved to be the most appropriate to determine the volatile oxo‐materials from vegetable oils. The method was successfully applied to follow up the formation of volatile substances (e.g. hexanal, t‐2‐hexenal, t‐2‐heptenal, t‐2‐octenal, nonanal, t, t‐2, 4‐nonadienal, t‐2‐nonenal, t‐2‐decenal, t, c‐ and t, t‐2, 4‐decadienal, 2‐pentylfuran, 1‐octen‐3‐ol) during deep frying in sunflower oil.     

Capability of SPME Technology for Dioxin Measurements in Air Phase

Dioxins are among aromatic compounds that at present arouse the most part of discussions as environment pollutants. In the present works from the French norm AFNOR, there is no simple way of sampling and analysis for gas emissions. Solid-phase microextraction (SPME) proves to be an adapted technology for dioxin sampling in gaseous phase due to its rapidity, reliability, and simplicity of material. In this study, a sample preparation method with a 100 w m polydimethylsiloxane fiber interfaced with a gas chromatography has been optimized for a monochlorinated dibenzo- p -dioxin: exposure of the fiber into the gaseous sample during 1 hr at 125°C. The partition coefficient fiber/matrix of the 1-monochlorinated dibenzo- p -dioxin has also been calculated versus temperature (K = 5.85 at 125°C).     

Biodiesel (FAME) Productivity,Catalytic Efficiency and Thermal Stability of Lipozyme TL IM for Crude Palm Oil Transesterification with Methanol

Crude palm oil (CPO) transesterification with methanol at room temperature is an important factor for optimizing biodiesel processing costs with respect to energy input; in addition, good stability of expensive lipase activity was ensured and is reported in this study. The enzyme loading, agitation speed and reaction time at a constant operating temperature of 30 °C were studied to find favourable operational conditions using a factorial design. Statistical analysis was used to assist the enzymatic transesterification so that a reduced mass transfer effect was achieved to obtain high FAME yields. The combination of optimum enzyme loading of 6.67 wt% and 150 rpm agitation speed for the system at 30 °C gave 81.73% FAME yield at 4 h and a production rate of 85.86% FAME yield/h. The high viscosity of CPO observed at 30 °C compared to 40 °C hindered the achievement of 96.15% FAME yield at room temperature. It was found that an increase of 10 °C invariably deactivated the lipase, but was compensated by the enhanced FAME production rate with 96.15% FAME yield after only 4 h reaction time. Thus, 40 °C was considered the most suitable operating temperature for lipozyme TL IM to catalyze CPO transesterification.     

Separation of vitamin E (tocopherol,tocotrienol, and tocomonoenol) in palm oil

Previous reports showed that vitamin E in palm oil consists of various isomers of tocopherols and tocotrienols [α-tocopherol (α−T), α-tocotrienol, γ-tocopherol, γ-tocotrienol, and δ-tocotrienol), and this is normally analyzed using silica column HPLC with fluorescence detection. In this study, an HPLC-fluorescence method using a C₃₀ silica stationary phase was developed to separate and analyze the vitamin E isomers present in palm oil. In addition, an α-tocomonoenol (α−T₁) isomer was quantified and characterized by MS and NMR. α−T₁ constitutes about 3–4% (40±5 ppm) of vitamin E in crude palm oil (CPO) and is found in the phytonutrient concentrate (350±10 ppm) from palm oil, whereas its concentration in palm fiber oil (PFO) is about 11% (430±6 ppm). The relative content of each individual vitamin E isomer before and after interesterification/transesterification of CPO to CPO methyl esters, followed by vacuum distillation of CPO methyl esters to yield the residue, remained the same except for α−T and γ−T₃. Whereas α−T constitutes about 36% of the total vitamin E in CPO, it is present at a level of 10% in the phytonutrient concentrate. On the other hand, the composition of γ−T₃ increases from 31% in CPO to 60% in the phytonutrient concentrate. Vitamin is present at 1160±43 ppm, and its concentrations in PFO and the phytonutrient concentrate are 4,040±41 and 13,780±65 ppm, respectively. The separation and quantification of α−T₁ in palm oil will lead to more in-depth knowledge of the occurrence of vitamin E in palm oil.     

Aerobic Liquor Washing Improves the Quality of Crude Palm Oil by Reducing Free Fatty Acids and Chloride Contents

The presence of free fatty acids (FFA) and chloride contents in crude palm oil is not desirable because they have an impact on oil quality and food safety. This work presents a method to reduce these compounds by washing the crude palm oil (CPO) with treated aerobic liquor (AL). The effects of process parameters on the reduction of FFA and chloride in CPO and the resultant 3-monochloropropane-1,2 diol ester (3-MCPDE) formed after refining are investigated. The results show that the AL dosage, initial FFA content, mixing speed, and duration have significant influence on the reduction of FFA in the CPO. Meanwhile, the chloride content is reduced by approximately 50% regardless of the AL dosage used. Consequently, the 3-MCPDE content in the oil after refining is up to 53% lower than that of the refined oil produced from the untreated CPO. Furthermore, an oil recovery above 97% can be achieved after the AL-washing step. The implementation strategy of this method in the palm oil mills has also been proposed. In conclusion, an effective and sustainable method for in situ improvements of the quality and food safety of palm oil has been developed without the need for additional water or chemical. Practical Applications: Treated aerobic liquor can be used to wash the CPO in palm oil mill for in situ reductions of FFA and chloride contents in CPO to improve the oxidative stability of CPO. The lower content of chlorides in CPO could mitigate the formation of 3-MCPDE during refining, thus improving the food safety of palm oil. This method can readily be implemented by the industry and it is sustainable because it does not require the use of additional process water or chemical.     

The effect of carotene extraction system on crude palm oil quality, carotene composition, and carotene stability during storage

Palm carotene was successfully concentrated from crude palm oil (CPO) by an adsorption process using a synthetic adsorbent followed by solvent extraction. Evaluation of feed CPO and CPO which underwent the carotene extraction process was conducted. The quality of CPO after the extraction process was slightly deteriorated in terms of free fatty acid, moisture content, impurities, peroxide value, anisidine value, discriminant function, and deterioration of bleachability index. However, the CPO still can be refined to produce refined, bleached, deodorized palm oil that meets the Palm Oil Refiners Association of Malaysia specifications. No extra cost was incurred by refining this CPO as the dosage of bleaching earth used was very similar to the refining of standard CPO. The triglyceride carbon number and fatty acid composition of CPO after going through the carotene extraction process were almost the same as CPO data. The major components of the carotene fraction were similar to CPO, which contains mainly α- and β-carotene. The carotene could be stored for at least 3 mon.     

Effects of Degumming and Bleaching on 3-MCPD Esters Formation During Physical Refining

Crude palm oil (CPO) was physically refined in a 200-kg batch pilot refining plant. A study of the possible role of degumming and bleaching steps in the refining process for a possible critical role in the formation of 3-chloropropane-1,2-diol (3-MCPD) esters was evaluated. For the degumming step, different percentages of phosphoric acid (0.02–0.1%) as well as water degumming (2.0%) were carried out. Six different types of bleaching clays, mainly natural and acid activated clays were used for bleaching process at a fixed dose of 1.0%. Deodorization of the bleached oils was performed at 260 °C for 90 min. Analyses showed that 3-MCPD esters were not detected in the CPO. Phosphoric acid degumming (0.1%) in combination with acid activated clays produced the highest levels (3.89 ppm) of 3-MCPD esters in the refined (RBD) oil. The esters were at the lowest levels (0.25 ppm) when the oil was water degummed and bleached with natural bleaching clays. However, the refined oil qualities were slightly compromised. Good correlation of 0.9759 and 0.9351 was obtained when concentration of the esters was plotted against acidity of the bleaching earths for the respective acid and water degumming processes. The findings revealed the contribution of acidic conditions on the higher formation of 3-MCPD esters. In order to lower the esters formation, it is important to reduce acid dosage based on the crude oil qualities or to find alternatives to acid degumming process. Neutralization of the acidity prior to deodorization was effective in reducing the formation of 3-MCPD esters.     

Photoinduced and thermal oxidation of rapeseed and sunflower oils

The aim of the present study was to compare oxidative stability of different sunflower and rapeseed oils. Ultra violet (UV) irradiation was used as an accelerator of the oil oxidation process. After UV irradiation, the formed volatile compounds were extracted by headspace solid‐phase microextraction HS‐SPME (DVB/CAR/PDMS fibre) and analysed by gas chromatography coupled with a flame ionization detector (GC/FID). At the same time, the same oil samples were thermally oxidized. The induction periods were determined on the basis of hexanal to 2‐trans‐nonenal ratio in the analysed samples. Finally, the obtained results were compared with induction period values obtained through the determination of peroxide and anisidine values, and from the Rancimat method, manostatic test and differential scanning calorimetry (DSC) method. The results obtained using the new method were well correlated with those achieved with the well‐established analytical techniques. The values of the induction period obtained after UV/HS‐SPME/GC/FID were up to three times higher than those from Rancimat, but the correlation between these two methods was on a very good level (correlation coefficient R>0.98). Similar correlation was also observed between these new methods and the DSC or manostatic test. In all cases, better results were obtained for rapeseed oils than sunflower oils.     

Ionic Liquid Based Headspace Solid-Phase Microextraction-Gas Chromatography for the Determination of Volatile Polar Organic Compounds

Solid-phase microextraction (SPME) with an ionic liquid (IL) coating was developed for headspace extraction of a group of low molecular weight alcohols (ethanol, n-propanol, butanol, and isopropyl alcohol), acetone, ethyl acetate, and acetonitrile. A first SPME fiber was simply coated with a dedicated IL whose synthesis is described. A second SPME fiber was prepared by gluing silica (Si) particles on which the synthesized IL was chemically bonded. The analytes SPME extraction was optimized for time, temperature, and NaCl salting out content. The headspace extracted analytes were determined by simple temperature desorption into the hot injection port of a gas chromatograph. The coated-IL fiber did not have enough extracting material to be useful. The bonded-IL-Si particle fiber had much more extracting material. Its analytical capabilities were compared to those of two commercially available fibers. The extraction yields of the bonded-IL-Si fiber were inferior to those of the two commercial fibers because they contained a significantly higher amount of extracting material. The linear concentration range could reach up to 120 μg/mL. The recoveries, trueness, and precision (RSD) were in the 97.4–109.5%, 0.1–9.5%, and 0.7–16.5 ranges, respectively. The bonded-IL-Si fiber showed a specific affinity for ethanol giving an ethanol peak height equal or greater than that of the two commercial fibers tested with the same sample.     

Composition and thermal profile of crude palm oil and its products

Gas-liquid chromatography and high-performance liquid chromatography (HPLC) were used to determine fatty acids and triglyceride (TG) compositions of crude palm oil (CPO), refined, bleached, and deodorized (RBD) palm oil, RBD palm olein, and RBD palm stearin, while their thermal profiles were analyzed by differential scanning calorimeter (DSC). The HPLC chromatograms showed that the TG composition of CPO and RBD palm oil were quite similar. The results showed that CPO, RBD palm oil, RBD olein, and superolein consist mainly of monosaturated and disaturated TG while RBD palm stearin consists mainly of disaturated and trisaturated TG. In DSC cooling thermograms the peaks of triunsaturated, monosaturated and disaturated TG were found at the range of −48.62 to −60.36, −25.89 to −29.19, and −11.22 to −1.69°C, respectively, while trisaturated TG were found between 13.72 and 27.64°C. The heating thermograms of CPO indicated the presence of polymorphs β₂′, α, β₂′, and β₁. The peak of CPO was found at 4.78°C. However, after refining, the peak shifted to 6.25°C and became smaller but more apparent as indicated by RBD palm oil thermograms. The heating and cooling thermograms of the RBD palm stearin were characterized by a sharp, high-melting point (high-T) peak temperature and a short and wide low-melting point (low-T) peak temperature, indicating the presence of occluded olein. However, for RBD palm olein, there was only an exothermic low-T peak temperature. The DSC thermograms expressed the thermal behavior of various palm oil and its products quite well, and the profiles can be used as guidelines for fractionation of CPO or RBD palm oil.     

一种新型固相微萃取涂层的研制与应用

制备了作为固相微萃取（SPME）涂层的硅酮弹性体一聚氨酯共混物,考察了该共混物的物理性能;制作了SPME装置;用顶空萃取法对水中芳香化合物进行了萃取实验。实验结果表明：涂层最高使用温度为240℃;萃取头表面平整,涂层内硅（Si）元素分布均匀;涂层对水中苯、氯苯、硝基苯萃取的色谱峰高与浓度线性关系良好且灵敏度高,各自的检出限分别为4．22μg／L、9．36μg/L和、5．01μg/L,结果令人满意。     

Integrated supercritical fluid extraction and subcritical water hydrolysis for the recovery of bioactive compounds from pressed palm fiber

Pressed palm fiber (PPF), a residue obtained from palm oil industry, is a source of bioactive compounds, such as carotenoids, which are used as food additives. It also has cellulose and hemicellulose that can be used to yield fermentable sugars for the production of second generation ethanol. Supercritical fluid extraction (SFE) of pressed palm fiber provides an oil rich in carotenoids while subcritical water hydrolysis (SubWH) produces hydrolysates with high amounts of fermentable sugars. In this work, the effects of pressure (15–30 MPa) and temperature (318 and 328 K) on SFE of carotenoids were investigated. The SFE extract with highest carotenoid content was obtained at 318 K and 15 MPa (2.3% d.b., 0.81 mg β-carotene/g extract). After the extraction, the influence of process temperature (423–633 K), pressure (15 and 25 MPa), solvent:feed ratio (120 and 240), and residence time (1.25–5 min) on SubWH of the extraction residue was studied. At the temperature of 523 K, the highest total reducing sugar yield (11–23 g glucose/100 g carbohydrate) and the highest biomass conversion (40–97%) were obtained for any pressure and solvent:feed ratio. The highest selectivity for saccharide formation was found at 423 K (20–59 mol glucose/mol furfural equivalent). Optimal conditions for high saccharide formation and low sugar degradation product in subcritical hydrolysis were obtained at 523 K, 15 MPa, solvent:feed ratio of 120, residence time of 2.5 min with a total reducing sugar yield of 22.9 g glucose/100 g carbohydrate and a conversion of 84.9%.     

Development of dual stage solvent fractionation as an approach to concentrate carotenoids from crude palm oil with high recovery: The potential use of molecular simulation as a pre-screening tool

Crude palm oil (CPO) is highly abundant in carotenoids. Previous findings found that dry fractionation can concentrate carotenoids from CPO but resulted in a significant loss of carotenoids. Therefore, the present study aimed to utilize solvent fractionation, which offers a better separation efficiency, to concentrate carotenoids from CPO with improved recovery. Computational study revealed a high binding affinity of phytonutrient towards unsaturated triacylglycerols (TAGs) species in olein fraction due to similar polarity. This prediction was further verified with evidence showing strong, positive correlation between the iodine value and carotenoids concentrations of fractionated oil. The difference in binding affinity of saturated and unsaturated TAG towards different solvents can be used as a guide for screening and selection of solvent suitable for recovery of phytonutrient during solvent fractionation. Subsequently, a lab-scale single- stage fractionation study disclosed that crystallization temperature of 15°C, oil to acetone ratio of 1:5 (w/v) for 4 h under agitation at 100 rpm produced olein with the highest carotenoid concentration (637 ppm) and recovery (94%). Subsequent double-stage fractionation successfully concentrated the carotenoids up to 125% with a recovery of >93%. Conclusively, solvent fractionation provides an effective way to concentrate valuable carotenoids from CPO while minimizing the lost.     

SPME联用GC/ECD测定饮水中氯酚

固相微萃取(SPME)是国际上1990s新发展起来的一项样品前处理技术。氯酚类化合物是环境中广泛存在的有机污染物，其中2,4-二氯酚(DCP)，2,4,6-三氯酚(TCP)和五氯酚(PCP)已被列为我国水体中优先控制物［3］和饮用水控制标准。国家现行饮用水检测标准方法中样品前处理采用固相萃取(SPE)法。本研究应用SPME联用GC/ECD检测饮水中3种氯酚，讨论实验条件对分析的影响，并和SPE法进行比较。表明SPME法在检测限、精密度、操作性等方面优于现行标准方法。