不同酯基结构的棕榈油生物柴油的性能研究

以棕榈油为研究对象,分别与甲醇、乙醇、异丙醇和异丁醇进行酯交换反应制备了不同酯基结构的生物柴油。利用差示扫描量热仪和应力控制流变仪分析了不同酯基结构棕榈油生物柴油的结晶行为和低温流变性能,同时分析了酯基结构对生物柴油的氧化稳定性,40℃时的动力黏度、20℃时的密度等重要性质的影响。结果表明,随着醇的碳链长度的增加,棕榈油生物柴油的析蜡点和胶凝点均降低,特别是棕榈油异丁酯的析蜡点和胶凝点分别降低到了-2.57和-8.09℃,低温流动性得到了明显改善,且氧化诱导期略有延长,氧化稳定性有所改善。生物柴油的密度和黏度随着酯基结构的不同而有所变化,但其数值都符合中国生物柴油标准。     

Preparation of Low-Diacylglycerol Cocoa Butter Equivalents by Hexane Fractionation of Palm Stearin and Shea Butter

Herein, we prepared 1,3-dipalmitoyl-2-oleoyl glycerol (POP)-rich fats with reduced levels of diacylglycerols (DAGs), adversely affecting the tempering of chocolate, via two-step hexane fractionation of palm stearin. DAG content in the as-prepared fats was lower than that in POP-rich fats obtained by previously reported conventional two-step acetone fractionation. Cocoa butter equivalents (CBEs) were fabricated by blending the as-prepared fats with 1,3-distearoyl-2-oleoyl glycerol (SOS)-rich fats obtained by hexane fractionation of degummed shea butter. POP-rich fats achieved under the best conditions for the fractionation of palm stearin had a significantly lower DAG content (1.6 w/w%) than that in the counterpart (4.6 w/w%) prepared by the previously reported method. The CBEs fabricated by blending the POP- and SOS-rich fats in a weight ratio of 40:60 contained 63.7 w/w% total symmetric monounsaturated triacylglycerols, including 22.0 w/w% POP, 8.6 w/w% palmitoyl-2-oleoyl-3-stearoyl-rac-glycerol, 33.1 w/w% SOS, and 1.3 w/w% DAGs, which was not substantially different from the DAG content in cocoa butter (1.1 w/w%). Based on the solid-fat content results, it was concluded that, when these CBEs were used for chocolate manufacture, they blended with cocoa butter at levels up to 40 w/w%, without distinctively altering the hardness and melting behavior of cocoa butter.     

棕榈壳酶解-温和酸解木质素的结构及热解特性研究

采用酶解/温和酸解法提取了棕榈壳和麦秆的木质素(EMALs),利用傅里叶红外光谱(FT-IR)、裂解器-气相色谱质谱联用(Py-GC/MS)和热重-红外联用(TG-FTIR)技术,对两种EMALs的化学结构和热解特性进行了对比研究,并采用Ozaw a-Flynn-Wall方法计算了其热解反应的活化能。结果表明,棕榈壳EM AL和麦秆EM AL均为HGS型木质素。500℃下,两种EMALs的热解产物主要包括酚类、酸类和少量的醇类、醛酮类等化合物;棕榈壳EMAL热解酚类产物中H、G、S型单体酚类的比例分别为47.61%、25.64%和17.18%,而麦秆EMAL分别为23.66%、51.90%和15.50%。在热解反应主失重区(200-380℃),棕榈壳EM AL的主失重速率(50.80%/min)低于麦秆EM AL(78.63%/min);但棕榈壳EM AL热解同时存在肩状失重峰(265℃,27.40%/min),这与其较多H结构产物的释放相关。H型结构产物释放的放热效应降低了棕榈壳EMAL热解初期的活化能(20%,127.92 k J/mol),同时使其热解过程(20%-80%)的平均活化能(152.32 k J/mol)低于麦秆EMAL(161.75 k J/mol)。     

Lipase immobilized on hydrophobic microporous polypropylene for the hydrolysis of palm kernel olein

Lipase (triacylglycerol ester hydrolase, EC 3.1.1.3) fromRhizopus arrhizus was immobilized in this work by adsorption on microporous polypropylene and employed for the lipolysis of palm kernel olein. The optimum operating temperature for the lipolysis reaction was determined. The reaction follows Michaelis-Menten kinetics with product competitive inhibition for substrate concentrations in the range of 0.175–0.877M. The apparentK _m and V_max were 0.42M and 691 U/mg protein, respectively. A dissociation constant of the enzymeproduct complex,K _I = 29.73 mM, for the product inhibition was also determined. Additionally, the time-courses of the reaction for various substrate concentrations were obtained and correlated sufficiently with those predicted from the theoretical rate equation for a period of up to 2 h. Experimental results indicated that discrepancies between the observed results and the predicted ones increase with reaction time.     

棕榈壳焦CO2气化过程中反应性及结构特性研究

850℃下,利用管式炉制备了不同转化率的棕榈壳CO₂气化焦,通过热重分析仪研究了气化焦的CO₂气化反应性,采用比表面积分析、拉曼光谱、X射线荧光光谱和扫描电镜-能谱等分析手段,考察了气化焦孔隙结构、碳组成、矿物元素含量与分布随转化率的变化。结果表明,在CO₂气化过程中,随着转化率的提高,棕榈壳气化焦固定碳的含量逐渐降低,有序化碳的相对含量为0.30~0.33,对气化过程起到一定的抑制作用;灰分含量逐渐增加,但气化反应指数R_s呈现先降低后升高的过程。转化率小于23%时,R_s与气化焦比表面积的变化趋势一致;23%< 转化率< 31%时,R_s基本不变;31%< 转化率< 68%时,比表面积随转化率线性增加,R_s取决于孔隙比表面积、矿物元素催化2个因素的协同作用,当转化率> 56 %时,该催化作用变得明显,同时碳的有序化程度开始降低;转化率> 68%时,R_s主要受矿物元素的催化作用控制。     

Molecular distillation process for recovering biodiesel and carotenoids from palm oil

Carotenoids and biodiesel from palm oil were recovered through a process involving neutralization and transesterification of palm oil followed by molecular distillation of the esters. The concentrated obtained contains more than 30,000 ppm of carotenoids and the distillate contains above 95% of light-colored biodiesel. The experimental data were obtained from falling film and centrifugal molecular distillators. It can be seen that each one has its own characteristics, which are a function of the operating temperatures and of the tendency of the material thermal decomposition. These characteristics can determine the type of equipment to be used, since they have different operating conditions. The experimental results were compared to the ones from simulations using the mathematical modeling for the falling film and centrifugal distillators developed.     

Chain cleavage mechanism of palm kernel oil derived medium-chain-length poly(3-hydroxyalkanoates) during high temperature decomposition

Medium-chain-length poly(3-hydoxyalkanoates) (mcl-PHAs) are natural polyesters having the molecular formula of [∼OCHR-CH₂-COO∼]_n, composed of monomers each having 6 to 14 carbon atoms, with relatively bulky alkyl pendant group. They are primarily synthesized by fluorescent pseudomonads under unbalanced nutrient availability as carbon and energy storage compounds. From thermogravimetic analysis, the mcl-PHAs produced from Pseudomonas putida grown on palm kernel oil showed a drastic decomposition at temperature above 195 °C. An increase of HO-CHR∼∼ terminals was observed when the mcl-PHAs were thermally decomposed at 160-180 °C, which was presumably due to the hydrolytic chain cleavage initiated at -COO-CHR∼∼, the main skeletal bonds of the biopolyester. At 190 °C, molecules with RCH≡CH∼∼ were also observed as minor decomposition products from the FTIR and NMR measurements and this could be probably due to the dehydration of HO-CHR∼ groups of hydroxyl acids, producing terminally unsaturated oligomers. These observations were consistent with the detection of three new unsaturated monomers: C_4:1, C_6:1 and C_8:1 in the methanolyzed mcl-PHAs in gas chromatography analysis.     

Controlled biosynthesis and characterization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) from mixtures of palm kernel oil and 3HV-precursors

This study investigates the biosynthesis and characterization of P(3HB-co-3HV-co-3HHx) terpolymer from mixtures of palm kernel oil and 3HV-precursors by using recombinant Cupriavidus necator PHB⁻4/pBBREE32d13. Sodium valerate and propionate have been evaluated for the generation of 3HV monomers. The feeding time of these precursors was a crucial factor that significantly affected the 3HV molar fractions, which ranged from 2 to 60 mol%. Sodium valerate was generally the better precursor in initiating the accumulation of 3HV monomers while maintaining high cell dry weight (7.9 g/L) and good PHA accumulation (79 wt%). However, the 3HHx molar fractions in the terpolymers at 72 h were consistent at about 2-7 mol%. P(3HB-co-3HV) copolymers have been known to exhibit approximately the same degree of crystallinity throughout a wide range of 3HV composition. Interestingly, in this study, terpolymers containing 58 mol% 3HB, 39 mol% 3HV and 3 mol% 3HHx showed elastomeric behavior. This study demonstrates the suitability of palm kernel oil as the main carbon source and both sodium propionate and sodium valerate as 3HV-precursors for the synthesis of novel compositions of P(3HB-co-3HV-co-3HHx) terpolymers with interesting properties.     

Adsorption of cadmium and lead from palm oil mill effluent using bone-composite: optimisation and isotherm studies

The adsorption of Cd and Pb ions from palm oil mill effluent on a mesoporous-activated cow bone composite powder has been investigated. Adsorbent was developed from cow bones, coconut shells and zeolite. The composite examined in the present work has a BET surface area of 248.398 m²/g. The optimisation of the removal efficiency of the heavy metals was investigated using central composite design and analysed using response surface methodology. The analysis of variance of the quadratic model signified that the model suitably predicted the uptake of the heavy metal ions at a 95% confidence level. The optimal operating condition was recorded at pH 4, 50 rpm, within 24 h and 1 mm of particle size and 12.5 gL^?1 of adsorbent dosage. The characteristics of the composite were investigated using the Fourier transform irradiation. The morphology and chemical composition of composite was examined using the scanning electron microscopy equipped with energy dispersive x-ray. Characterisation study was conducted before and after the adsorption process. The results obtained illustrated that the removal of cadmium and lead from POME was influenced by the functional groups available on the surface of the composite. The carboxyl and hydroxyl groups are mainly responsible for the removal of cadmium and lead through chelating process. The point of zero charge (pH_pzc) revealed that the adsorbent contained acidic sites with negatively charge surface which influenced the adsorption process. The experimental data of the heavy metals of Cd and Pb investigated were fitted to the Langmuir and Freundlich models. The result revealed that the adsorption equilibrium data fitted better to the Langmuir model for the adsorption Cd and to the Freundlich model for the adsorption of Pb.     

DSC studies on the polymorphism and pseudopolymorphism of pharmaceutical substances

A complex system including thermoanalytical methods, infrared spectroscopy and X-ray powder diffraction for studying physico-chemical behaviour of binary mixtures is described. This system has been tested by investigating binary mixtures of amphetamine hydrochloride salts.These studies have proved that among the selected compounds the primary and secondary amine hydrochloride salts exhibit conglomerate forming tendency, while the tertiary amine hydrochloride salts form molecular compounds (racemates). For thep-fluoro amphetamine hydrochloride the existence of two polymorphic modifications has been detected.The authors are grateful to D. Kozma (Department of Organic Chemical Technology) for the thermoanalytical data of compound III, to Prof. E. Fogassy for the fruitful discussion.     

Computational simulation of palm kernel oil-based esters nano-emulsions aggregation as a potential parenteral drug delivery system

The self-assembled structure of palm kernel oil-based esters (PKOEs) nano-emulsions has shown a great potential used for parenteral drug delivery applications. Here, all-atom level molecular dynamics (MD) was applied to investigate the aggregation process of PKOEs nano-emulsion system. The system consisted of palm kernel oil-based esters (PKOEs) and dipalmitoylphosphatidylcholine (DPPC) in water. The ratio of all constituents was taken from the homogenous region of a ternary phase diagram determined experimentally. The molecules started to aggregate very rapidly from random configurations. A doughnut-like toroidal assembled structure formed at 50 ns with PKOEs surrounded by DPPC molecules. The structural and dynamical properties of the self-assembled doughnut-like toroidal aggregate were analyzed using the principle moment of inertia, eccentricity and radius of gyration. The aggregation structures were compact with the average radius of gyration of 4.10 (±0.02) nm over the last 5 ns. Additionally, both hydrophobic and hydrophilic interactions were involved in aggregation process with a total solvent accessible surface area of 551.72 (±5.88) nm².     

Investigation of the complex thermal behavior of fats

The thermal behavior of three ural fats (displaying very different composition), cocoa butter (CB)², lard, and a stearin obtained from anhydrous milk-fat (AMF) fractionation, were studied by both DSC and X-ray diffraction as a function of temperature (XRDT). To perform temperature explorations between –30C and +80C, at rates identical to those used for DSC and ranging from 0.1 K min^–1 to 10 K min^–1, a new set of X-ray sample-holders, temperature-controlled by Peltier effect, has been developed. It is shown that the three more stable polymorphic forms of CB were easily characterized by either X-ray diffraction or DSC, and existence of two -3L forms was confirmed. On the contrary, the more complex polymorphism of lard and AMF required combined examination by DSC and XRDT and the brightness of the synchrotron source for studies at the highest heating rates. Quantitative analysis of the long spacings of XRDT recordings is invaluable for interpretation of thermal events. For instance, it was found that the simultaneous formation of two polymorphic forms, of apparent long spacing of 34 and 42 å, at the onset of lard crystallization might explain the difficulty of its fractionation.Special thanks to Courtney P. Mudd (NIH, Bethesda) for his pertinent advice on the mounting and use of thermoelectric devices. The study of lard crystallization was initiated by Valerie Portalier and suggested by Jean-Luc Vendeuvre of CTSCCV (Maisons-Alfort). For the AMF part of this study, stearin was fractionated by ADRIA Normandie, while characterization of its thermal properties was performed as part of a research program funded by ARILAIT Recherches and the French Ministry of Research and Technology.     

Utilization of agro-resources by radiation treatment -production of animal feed and mushroom from oil palm wastes

The production of animal feeds and mushrooms from oil palm cellulosic wasres by radiation and fermentation has been investigated in order to utilize the agro-resources and to reduce the smoke pollution. The process is as follows: decontamination of microorganisms in fermentation media of empty fruit bunch of oil palm (EFB) by irradiation, inoculation of useful fungi, and subsequently production of proteins and edible mushrooms. The dose of 25 kGy was required for the sterilization of contaminating bacteria whereas the dose of 10 kGy was enough to eliminate the fungi. Among many kinds of fungi tested, C. cinereus and P. sajor-caju were selected as the most suitable microorganism for the fermentation of EFB. The protein content of the product increased to 13 % and the crude fiber content decreased to 20% after 30 days of incubation with C. cinereus at 30°C in solid state fermentation. P. sajor-caju was suitable for the mushroom production on EFB with rice bran.     

Enzyme production and profile by Aspergillus niger during solid substrate fermentation using palm kernel cake as substrate

The oil palm sector is one of the major plantation industries in Malaysia. Palm kernel cake is a byproduct of extracted palm kernel oil. Mostly palm kernel cake is wasted or is mixed with other nutrients and used as animal feed, especially for ruminant animals. Recently, palm kernel cake has been identified as an important ingredient for the formulation of animal feed, and it is also exported especially to Europe, South Korea, and Japan. It can barely be consumed by nonruminant (monogastric) animals owing to the high percentages of hemicellulose and cellulose contents. Palm kernel cake must undergo suitable pretreatment in order to decrease the percentage of hemicellulose and cellulose. One of the methods employed in this study is fermentation with microorganisms, particularly fungi, to partially degrade the hemicellulose and cellulose content. This work focused on the production of enzymes by Aspergillus niger and profiling using palm kernel cake as carbon source.     

A novel approach to the rapid assignment of 13C NMR spectra of major components of vegetable oils such as avocado,mango kernel and macadamia nut oils

Assignment of ¹³C nuclear magnetic resonance (NMR) spectra of major fatty acid components of South African produced vegetable oils was attempted using a method in which the vegetable oil was spiked with a standard triacylglycerol. This proved to be inadequate and therefore a new rapid and potentially generic graphical linear correlation method is proposed for assignment of the ¹³C NMR spectra of major fatty acid components of apricot kernel, avocado pear, grapeseed, macadamia nut, mango kernel and marula vegetable oils. In this graphical correlation method, chemical shifts of fatty acids present in a known standard triacylglycerol is plotted against the corresponding chemical shifts of fatty acids present in the vegetable oils. This new approach (under carefully defined conditions and concentrations) was found especially useful for spectrally crowded regions where significant peak overlap occurs and was validated with the well‐known ¹³C NMR spectrum of olive oil which has been extensively reported in the literature. In this way, a full assignment of the ¹³C{1H} NMR spectra of the vegetable oils, as well as tripalmitolein was readily achieved and the resonances belonging to the palmitoleic acid component of the triacylglycerols in the case of macadamia nut and avocado pear oil resonances were also assigned for the first time in the ¹³C NMR spectra of these oils. Copyright © 2009 John Wiley & Sons, Ltd.     

Development and Physicochemical Properties of Low Saturation Alternative Fat for Whipping Cream

We developed an alternative whipping cream fat using shea butter but with low saturation. Enriched stearic-oleic-stearic (SOS) solid fat was obtained from shea butter via solvent fractionation. Acyl migration reactant, which mainly contains asymmetric SSO triacylglycerol (TAG), was prepared through enzymatic acyl migration to obtain the creaming quality derived from the β’-crystal form. Through enzymatic acyl migration, we obtained a 3.4-fold higher content of saturated-saturated-unsaturated (SSU) TAG than saturated-unsaturated-saturated (SUS) TAG. The acyl migration reactant was refined to obtain refined acyl migration reactant (RAMR). An alternative fat product was prepared by blending RAMR and hydrogenated palm kernel oil (HPKO) at a ratio of 4:6 (w/w). The melting points, solid fat index (SFI), and melting curves of the alternative products were similar to those of commercial whipping cream fat. The alternative fat had a content of total unsaturated fatty acids 20% higher than that of HPKO. The atherogenic index (AI) of alternative fat was 3.61, much lower than those of whipping cream fat (14.59) and HPKO (1220.3), because of its low atherogenic fatty acid content and high total unsaturated fatty acids. The polymorphic crystal form determined by X-ray diffraction spectroscopy showed that the β’-crystal form was predominant. Therefore, the alternative fat is comparable with whipping cream that requires creaming quality, and has a reduced saturated fat content.     

QuEChERS-液相色谱-串联质谱法测定棕榈原油中敌草快等6种农药残留

建立了QuEChERS-液相色谱-串联质谱同时测定棕榈原油中敌草快、乐果、倍硫磷、倍硫磷亚砜、倍硫磷砜、氟吡甲禾灵残留量的方法。以回收率及基质效应为考察指标,评估了乙二胺-N-丙基硅烷(PSA)/C18混合物、C18键合锆胶(Z-Sep+)/C18混合物、Z-Sep+、C18 4种分散吸附剂的净化效果,结果表明Z-Sep+/C18的净化效果最佳。样品采用含1%(v/v)乙酸的甲醇溶液提取,Z-Sep+/C18分散固相萃取净化;液相色谱以Atlantis T3色谱柱梯度洗脱分离,质谱分析采用电喷雾正离子电离、多反应监测模式,以基质匹配校准曲线外标法进行定量。6种农药在3个添加水平(10、20、250 μg/kg)下的回收率范围为70.0%~97.9%,相对标准偏差范围为2.6%~10.2%; 6种农药的定量限(S/N≥10)为0.1~2.5 μg/kg。该方法简便、灵敏、准确、环保,适用于棕榈原油中上述6种农药残留的定性、定量分析。     

Structure and properties of partially epoxidized soybean oil

In the present study, the characteric-structure relationship of epoxidized soybean oils (ESO) with various degrees of epoxidation has been investigated. FTIR analysis was used to identify the relative extent of epoxidation of the samples during the epoxidation reaction. The viscosities of ESO were much higher than that of the raw oil, viscosity increased with degree of epoxidation. The viscous-flow activation energy of ESO was determined to be higher than that of the raw oil (20.72 to 77.93% higher). Thermogravimetry analysis (TG) of ESO was used to investigate the thermodynamic behavior of the samples. With increasing degree of epoxidation, the thermal stability of the samples initially decreased, then increased at the final reacting stage. Differential scanning calorimeter (DSC) indicated that the melting point of ESO was higher than that of soybean oil. Gel permeation chromatography (GPC) indicated the molecular mass of the samples increased initially, then decreased, with an increase in the extent of epoxidation.     

Catalytic behavior of Al2O3-TiO2 supported Pd-Ru bimetallic catalyst for the partial hydrogenation of palm oil

Summary Al₂O₃-TiO₂ supported Pd-Ru bimetallic catalysts were prepared and characterized by X-ray photoelectron spectroscopy and X-ray diffraction (XRD) techniques. The catalytic system was evaluated in the partial hydrogenation of palm oil. Based on these results, it was deduced that core-shell model particles, with Ru cores, would be most likely formed in the bimetallic catalysts. As a result, the dispersing effect of ruthenium on palladium and the charge transfer from ruthenium to palladium may be closely related to the excellent catalytic performance. Besides, the highly dispersed TiO₂ on γ-alumina support seems to be crucial for inhibiting the formation of trans fatty acid.     

Deciphering key proteins of oil palm (Elaeis guineensis Jacq.) fruit mesocarp development by proteomics and chemometrics

Palm oil is an edible vegetable oil derived from lipid‐rich fleshy mesocarp tissue of oil palm (Elaeis guineensis Jacq.) fruit and is of global economic and nutritional relevance. While the understanding of oil biosynthesis in plants is improving, the fundamentals of oil biosynthesis in oil palm still require further investigations. To gain insight into the systemic mechanisms that govern oil synthesis during oil palm fruit ripening, the proteomics approach combining gel‐based electrophoresis and mass spectrometry was used to profile protein changes and classify the patterns of protein accumulation during these complex physiological processes. Protein profiles from different stages of fruit ripening at 10, 12, 14, 15, 16, 18 and 20 weeks after anthesis (WAA) were analysed by two‐dimensional gel electrophoresis (2DE). The proteome data were then visualised using a multivariate statistical analysis of principal component analysis (PCA) to get an overview of the proteome changes during the development of oil palm mesocarp. A total of 68 differentially expressed protein spots were successfully identified by matrix‐assisted laser desorption/ionisation‐time of flight (MALDI‐TOF/TOF) and functionally classified using ontology analysis. Proteins related to lipid production, energy, secondary metabolites and amino acid metabolism are the most significantly changed proteins during fruit development representing potential candidates for oil yield improvement endeavors. Data are available via ProteomeXchange with identifier PXD009579. This study provides important proteome information for protein regulation during oil palm fruit ripening and oil synthesis.