Determination of iodine value of palm oil by differential scanning calorimetry

Iodine value (IV) is used as a parameter in process control as well as a quality parameter in traded palm oil products. IV measures the number of double bonds in the molecular structure of an oil. To form a double bond, carbon requires more energy (615 kJ/mol) than to form a single bond (350 kJ/mol). Therefore, the thermal behavior of an oil could reflect its iodine value. This study was conducted to demonstrate the use of a differential scanning calorimeter (DSC) to determine the IV of palm oil and its products as an attempt to reduce the use of chemicals in the analysis. The DSC thermograms of palm oil showed a clear separation of the substances that have low melting points (low-T), consisting of triunsaturated, monosaturated and disaturated triglycerides, from the high ones (high-T), consisting of trisaturated triglycerides. Regression analysis showed that the peak characteristics, namely, area and height of the low-T group and height of the high-T group in the heating thermogram and also the height of the high-T group in the cooling thermogram, can predict the IV of palm oil with R ² higher than 0.99. This study concludes that DSC can be used to determine the IV of palm oil and its products.     

Determination of iodine value of palm oil by fourier transform infrared spectroscopy

A rapid method for the quantitative determination of iodine value (IV) of palm oil products by FTIR transmission spectroscopy is described. A calibration standard was developed by blending palm stearin and superolein in specific ratios that covered a range of 27.9 to 65.3 IV units. The spectra of these standards was measured in the range between 3050 and 2984 cm⁻¹, corresponding to the absorption band of=C-H cis stretching vibration. A partial least squares calibration model for the prediction of IV was developed to quantify the IV of palm oil products. A validation approach was used to optimize the calibration with a correlation coefficient of R ²=0.9995 and a standard error of prediction of 0.151. This study concludes that the FTIR transmission approach can be used to determine the IV of palm oil products with a total analysis time per sample of less than 2 min for liquid samples.     

Determination of iodine value of palm and palmkernel oil by carbon‐13 nuclear magnetic resonance spectroscopy

High resolution carbon‐13 nuclear magnetic resonance ( ¹³ CNMR) can be used for characterization of palm oil and palmkernel oil in determining the iodine value (IV) of the oil. It is only necessary to obtain the quantitative ¹³ CNMR spectrum of the oil in dilute CDCl₃ solution in the region of δ30.0‐δ24.7 ppm, which pertains to the methylene carbons along the acyl chain from the β‐carbonyl to the ω‐4. From the peak areas in the spectrum the average number of double bonds per triacylglycerol molecule and the average molecular weight can be calculated and hence the IV. The IVs of 18 samples of palm and palmkernel oil have been determined by ¹³ CNMR and by the Official Method of the American Oil Chemists Society. There is good agreement between the two sets of IVs. Conditions for obtaining reliable IVs by this ¹³ CNMR method are given.     

Determination of iodine value of palm olein mixtures using differential scanning calorimetry

Differential scanning calorimetry (DSC) was used to determine the iodine value (IV) of various palm olein (PoO) mixtures. Eight different PoO mixtures, namely, PoO:PKO, PoO:CoO, PoO:PS, PoO:PO, PoO:CaO, PoO:OeO, PoO:CnO and PoO:SFO were prepared at different ratios (w/w) to give various IV (PKO represents palm kernel olein; CoO, coconut oil; PS, palm stearin; PO, palm oil; CaO, canola oil; OeO, olive oil; CnO, corn oil; and SFO, sunflower oil). Each sample was then scanned from 80 to ‐ 100 �C at ‐5 �C/min using a DSC. All the mixtures showed two exothermic peaks in their cooling thermograms, except PoO:SFO mixtures which showed three peaks. Results of stepwise multiple linear regression (SMLR) analysis showed that five independent variables extracted from each of these peaks, namely, on‐set temperature, off‐set temperature, peak temperature, peak height and peak enthalpy could predict well the IV of each mixture. The calibration models developed showed appreciable effectiveness, re‐producibility and accuracy, and specificity towards the calibration data set. A shared calibration model for each group of PoO mixtures i.e. high‐lauric (PoO:PKO and PoO:CoO), high‐palmitic (PoO:PS and PoO:PO) and high‐oleic (PoO:CaO and PoO:OeO) mixtures was also developed. SMLR analysis showed that the shared models were also capable in predicting IV of the PoO mixtures, even though the coefficient of determination, R² , was slightly lower than that of their individual models. The shared calibration models also had good reproducibility and accuracy when compared with the standard chemical method. In conclusion, DSC provides an effective method in determining IV for routine analysis in the industries, whereby one single model could be calibrated for the use of all oil and fat products that have similar chemical compositions such as high‐lauric, high‐palmitic or high‐oleic mixtures in the industry.     

Determination of cypermethrin in palm oil matrices

In this study, a new method was developed for the determination of cypermethrin residue in both crude palm oil (CPO) and crude palm kernel oil (CPKO) using GC with electron capture detector. In this method, the oil was extracted with acetonitrile. Aliquots were cleaned‐up using combined solid phase extraction (SPE), and a primary‐secondary amine in combination with graphitized carbon black. The SPE cartridges were first conditioned and then eluted with acetonitrile. Cypermethrin recoveries from the fortified CPO samples were 87–98% with relative standard deviation (RSD) values of 4–8%, while those for the fortified CPKO samples were 83–100% with RSD values of 3–10%. Since good recoveries were obtained with RSD values below 10% in most cases, the proposed methodology will be useful for the analyses of palm oil samples. The method was successfully applied to the analysis of cypermethrin in real palm oil samples from various parts of Malaysia. No cypermethrin residue was found among 30 samples analyzed.     

Lubrication properties of trimethylolpropane esters based on palm oil and palm kernel oils

Due to the global drive towards biodegradable products, trimethylolpropane [2‐ethyl‐2‐(hydroxymethyl)‐1, 3‐propanediol] (TMP) esters based on palm and palm kernel oils were synthesized, their lubrication properties evaluated, and their potential as base stock for biodegradable lubricants assessed. Two types of TMP esters were considered: palm kernel (PKOTE) and palm oil (PPOTE) TMP esters, derived from palm oil and palm kernel methyl esters, respectively. Lubrication properties such as viscosity, viscosity index (VI) and pour point (PP) were determined according to methods of the American Society for Testing and Materials. Wear and friction properties were evaluated using a four‐ball test machine, while oxidative stability was studied with the Penn State Micro‐oxidation thin‐film test. High VI ranges between 170 to 200 were recorded for these base stocks. PP were relatively high, between 4 to —1 °C, but were improved to at least —33 °C in high oleic palm oil TMP esters. The effects of chemical structure and impurities on wear properties and oxidative stability were also studied. The presence of methyl esters was found to improve wear, but hydroxyl groups in mono‐ and diesters had negative effects at high concentrations. Differences in chemical structures of PKOTE and PPOTE were shown to affect friction and wear results. Both base fluids exhibit oxidative stability comparable to other high oleic base fluids.     

Composition of the oil in palm kernel fromElaeis guineensis

The composition of oil from the outer, middle, and inner section of palm kernel had been evaluated by gas-liquid chromatography and nuclear magnetic resonance techniques. The composition was not homogenous throughout the kernel and was found to be more unsaturated in the outer kernel. The inner core of the kernel is less unsaturated, having a higher lauric content. The variation in the iodine value from the outer to inner section of the kernel suggested that composition of palm kernel oil was affected by the kernel size. This was found to be true, as small kernels tend to have oil with higher iodine value than do larger kernels.     

棕榈油市场分析

分析了2008年度的棕榈油市场发展状况,对2009年度的棕榈油市场进行了展望和预测。同时,对全球棕榈油库存及库存使用比以及在全球贸易中所占比例进行了分析。     

Determination of peroxide value in thermally oxidized crude palm oil by near infrared spectroscopy

A near infrared (NIR) spectroscopic method was developed to measure peroxide value (PV) in crude palm oil (CPO). Calibration standards were prepared by oxidizing CPO in a fermentor at 90°C. A partial least squares (PLS) calibration model for predicting PV was developed based on the NIR spectral region from 1350 to 1480 nm with reference to single-point baseline at 1514 nm. The optimization of calibration factors was guided by the predicted residual error sum of squares test. The standard error of calibration obtained was 0.156 over the analytical range of 2.17–10.28 PV and the correlation coefficient (R ²) was 0.994. The method was validated with an independent set of samples which was prepared in the same manner on a different day. A linear relationship between the American Oil Chemists’ Society and the NIR methods was obtained with R ² of 0.996 and standard error of performance of 0.17. This study has demonstrated that the prediction of PV in the NIR region is possible. The method developed is rapid, with total analysis time less than 2 min, is environmentally friendly, and its accuracy is generally good for quality control of CPO.     

Comparative evaluation of palm oil color measurement using a prototype palm oil colorimeter

The color of refined palm oil and palm oil products is conventionally measured using the manually operated Lovibond^® Tintometer. In the present study, one manual/visual and three automatic colorimeters for the measurement of vegetable oil color were used for color measurements of refined palm oil. All colorimeters used were commercially available instruments except for an automatic palm oil colorimeter developed specifically for the measurement of palm oil color. The color values obtained from all four instruments were compared using the visually obtained readings as reference values. Results showed that all three automatic instruments gave correlation coefficients of greater than 0.9300 for red color measurements. In addition, the Student t-test showed no difference between the analysis of red color using the visual method and the palm oil colorimeter. This investigation concludes that, although it is extremely difficult to reduce the lack of precision in color measurement of palm oil, a properly designed and calibrated automatic instrument may still be the better choice because reproducibility and repeatability are required in all standard test methods. The palm oil colorimeter offers a ready and relatively inexpensive solution to the problem of color matches based on visual observations.     

Determination of free fatty acids in crude palm oil and refined-bleached-deodorized palm olein using fourier transform infrared spectroscopy

A rapid direct Fourier transform infrared (FTIR) spectroscopic method using a 100 μ BaF₂ transmission cell was developed for the determination of free fatty acid (FFA) in crude palm oil (CPO) and refined-bleached-deodorized (RBD) palm olein, covering an analytical range of 3.0–6.5% and 0.07–0.6% FFA, respectively. The samples were prepared by hydrolyzing oil with enzyme in an incubator. The optimal calibration models were constructed based on partial least squares (PLS) analysis using the FTIR carboxyl region (C=O) from 1722 to 1690 cm⁻¹. The resulting PLS calibrations were linear over the range tested. The standard errors of calibration (SEC) obtained were 0.08% FFA for CPO with correlation coefficient (R ²) of 0.992 and 0.01% FFA for RBD palm olein with R ² of 0.994. The standard errors of performance (SEP) were 0.04% FFA for CPO with R ² of 0.998 and 0.006% FFA for RBD palm olein with R ² of 0.998, respectively. In terms of reproducibility (r) and accuracy (a), both FTIR and chemical methods showed comparable results. Because of its simpler and more rapid analysis, which is less than 2 min per sample, as well as the minimum use of solvents and labor, FTIR has an advantage over the wet chemical method.     

Improvement of palm oil through breeding and biotechnology

The oil palm Elaeis guineensis is the highest oil-yielding crop and has the potential to become the major supplier of both edible oil and renewable industrial feedstock. The oil yield from wild groves is presently less than 0.5 t/ha/y. However, through breeding and selection, the oil yield of commercial plantations could reach as much as 8 t/ha/y. New planting materials also have the capability of better oil yields with high iodine value (IV), slow height increment, and larger kernels. The oil also contains considerable amounts of carotenoids (500–700 ppm), vitamin E (600–1000 ppm), and sterols (250–620 ppm). The oil yield of another oil palm species, E. oleifera, is approximately 0.5 t/ha/y with high contents of carotenoids (700–1500 ppm), vitamin E (700–1500 ppm), and sterols (3500–4000 ppm). The above traits could be improved through breeding and biotechnology. Biotechnological efforts at the Palm Oil Institute of Malaysia are directed toward the production of oil with high IV and high monounsaturated fatty acids for edible purposes and industrial uses. Isolation and manipulation of the genes involved in the biosynthesis of fatty acids are the main focus. The aim is to increase the efficiency of conversion of palmitate (C_16:0) to oleate (C_18:1). Levels of palmitate and oleate are controlled by the enzymes acyl-acyl carrier protein (ACP) thioesterase and β-keto acyl ACP synthase II. The chain termination reactions of C_16:0 and C_18:1 are independent, thus paving the way for the possibility of reducing palmitate levels by switching off the palmitoyl ACP thioesterase gene. Paper presented at the 88th AOCS Annual Meeting & Expo. May 11–14, 1997, Seattle, Washington, USA.     

Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil

One of the major difficulties in using crude vegetable oils as substitute fuels in diesel engines is their relatively high viscosities. Increasing the temperature of the crude vegetable oil, blending it with diesel oil, or the combination of both offers a simple and effective means of controlling and lowering the viscosities of vegetable oils. This work reports viscosity data, determined with a rotational bob-and-cup viscometer, for crude palm oil and cononut oil blended with diesel oil over the temperature range of 20–80°C and for different mixture compositions. All the test oil samples showed a time-independent newtonian type of flow behavior. The reduction of viscosity with increasing liquid temperature followed an exponential relationship, with the two constants of the equation being a function of the volume percentage of the vegetable oil in the mixture. A single empirical equation was developed for predicting the viscosity of these fuel mixtures under varying temperatures and blend compositions.     

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.     

Co-metathesis reaction of crude palm oil and ethene

The co-metathesis reaction of crude palm oil with ethene in the presence of WCL₆/Me₄Sn, followed by termination of this reaction with methanol, gives terminal alkenes. The major metathesis products are 1-decene and methyl 9-decenoate.     

棕榈油在全球的贸易

深入阐述了棕榈油、月桂酸和工业油脂化学在马来西亚和印度尼西亚等生产大国的市场概况,进而看到棕榈油在全球的贸易。同时,也分析了棕榈油和月桂油在中国的市场状况和市场潜力,不管是对马来西亚还是整个世界来说,中国是非常重要的市场。     

Rheological behavior of crystallizing palm oil

The static isothermal crystallization of palm oil was studied by oscillatory rheology. The phase angle, complex modulus, storage modulus and loss modulus were followed as a function of the crystallization time. Various crystallization temperatures were applied, and the results obtained by oscillatory rheology were compared with crystallization data obtained by more classical techniques like differential scanning calorimetry (DSC) and pulsed nuclear magnetic resonance (pNMR). It was shown that oscillatory rheology is a valuable complementary method to DSC and pNMR to evaluate primary crystallization. Like DSC and pNMR, oscillatory rheology is capable of differentiating whether crystallization occurs in a two‐stage or a single‐stage process. In addition, oscillatory measurements also allow the evaluation of aggregation, network formation and post‐hardening events like sintering and thus provide information on the crystal network and the final macroscopic properties of the crystallized sample.     

Shear strength of wood to wood adhesive based on palm kernel oil

A polyurethane adhesive system was prepared by reacting a resin consisting of palm kernel oil‐based polyester and dimethyl cyclohexanediamine with an aliphatic adduct based on 2,4‐diphenylmethane diisocyanate (MDI). Brushing technique was used for applying the adhesive (of thickness 0.05–0.10 mm) onto the wood substrate. Shear strength test for substrates that have been exposed to moisture and various degrees of heat was carried out. Collected data indicated that the adhesive exposed to heat at 70°C has the highest shear strength. At this point, the shear force was at the maximum of 2562 N with strength of 2.65 MPa. However, at higher testing temperature, there is a decrease in the shear force and strength of the adhesive. The presence of moisture, however, does not affect much on the shear strength. The morphological observations via optical microscope were made to explain the relationship of heat and moisture with the shear strength of the adhesive. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1759–1764, 2006     

Conversion of oil palm trunk into bio-oil via treatment with subcritical water

Subcritical water was applied to produce bio-oil from a 21-year-old abandoned oil palm trunk (OPT). The effects of reaction temperature, time, part of trunk taken, and optimum reaction condition were investigated. Higher heating values (HHVs), CHNS/O elemental and GC-MS analysis were performed to characterize the bio-oil. The subcritical water temperatures were manipulated between 100?°C?and?370?°C with 10?°C intervals and the reaction time was varied between 6?s and 20?min. The maximum yield of bio-oil from subcritical water treatment of top and bottom part of OPT was 0.27 and 0.30?kg/kg-dry OPT, respectively. The optimum reaction time and temperature was 5?min and 330?°C. The highest HHV of the bio-oils derived from the top and bottom part of OPT was 33.2?MJ/kg and 26.4?MJ/kg, respectively. From GC-MS measurement, the bio-oil contained phenolic compounds. The bio-oil derived from OPT obtained from subcritical water treatment had high HHV and comparable to other liquid fuels.     

DSC study on the melting properties of palm oil, sunflower oil, and palm kernel olein blends before and after chemical interesterification

Changes in DSC melting properties of palm oil (PO), sunflower oil (SFO), palm kernel olein (PKOo), and their belends in various ratios were studied by using a combination of blending, and chemical interesterification (CIE) techniques and determining total melting (ΔH _f ) and partial melting (ΔH _i°C ) enthalpies. Blending and CIE significantly modified the DSC melting properties of the PO/SFO/PKOo blends. PO and blends containing substantial amounts of PO and PKOo experienced an increase in their DSC ΔH _f and ΔH _i°C following CIE. The DSC ΔH _f and ΔH _i°C of PKOo, blends of PO/SFO at 1∶1 and 1∶3 ratios, and all blends of PKOo/SFO significantly decreased after CIE. The DSC ΔH _f and ΔH _i°C of SFO changed little following CIE. Randomization of FA distribution within and among TAG molecules of PO and PKOo led to modification in TAG composition of the PO/PKOo blends and improved miscibility between the two fats and consequently diminished the eutectic interaction that occurred between PO and PKOo.