Category Archives: 2012 Vol 24 Aug

Characterisation of palm-based polyols by gel permeation chromatography with combined detectors

Gel permeation chromatography (GPC) with combined detectors, i.e. differential refractive index (DRI) and viscometer, was used to analyse molecular weight averages of palm-based polyol samples (POP Pioneer 100 and POP Pioneer derivatives, three types of POP Primer and a POP Premier). Elution was carried out using tetrahydrofuran as the mobile phase at 30°C at a flow rate of 1 ml min-1 on a PLgel Mixed D column. Narrow molecular weight distribution (MWD) polystyrene was used as the calibration standard to generate a universal calibration for quantification of the absolute molecular weight (MW) averages and MWD.

POP Pioneer 100 was found to have a number average molecular weight (Mn) ranging from 1861 to 2800 Daltons, a weight-average molecular weight (Mω) of 10 600 to 18 000 Daltons and polydispersity index (PDI) of 5.5 to 6.5 with a broad bimodal MWD. POP Pioneer derivatives had Mn ranging from 2500-2700 Daltons, Mw from 27 110-30 500 Daltons, PDI from 10.2-11.6 and a broad bimodal MWD. POP Premier had Mn from 1290-2215 Daltons, Mw from 17 700-21 500 Daltons and PDI from 7.8-16.7 with broad bimodal MWD. All three types of POP Primer showed close values of MW average with Mn between 1800 and 1900 Daltons, Mw from 7700-7900 Daltons, PDI from 3.8-4.2 and with a skewed bimodal MWD. The Mark-Houwink plots of palm-based polyols showed that the changes in their structures were insignificant over the range of MWD, except for POP Primer Types 2 and 3 where branching was more obvious at the higher end of the molecular weight.

Effects of severing oil palm roots on leaf nutrient levels and P uptake

Physical damage to oil palm roots affects the palm’s ability to acquire nutrients. In spite of this huge impact on the palm, the effects of root loss on palm nutrient status are unknown and this is unfortunate because optimal palm nutrient status is an important factor in fruit production.

In trying to understand the effects of damage to the roots and the consequent effects on the palms, the impact of root damage was simulated by severing roots within 0%, 25% and 50% of the palm circle. Five months after the roots were severed, changes in leaf nutrient levels in the various treatments were observed. Each treatment was replicated five times, using one palm per replicate.

The impact of losing 25% of the roots within the palm circle changed the leaf K concentration and also the N:K ratio significantly (p < 0.05) compared with a loss of 50% of the roots within the palm circle. However, palms which lost 25% and 50% of the roots within the palm circle did not show any significant change (p> 0.05) in the N, P, Mg and B leaf concentrations compared to control.

Further assessment of the impact of root loss on nutrient uptake by the palm, especially by the surviving tertiary roots, was made using 32P isotope. Five surviving tertiary roots from each treatment were placed in contact with the 32P solution, and the amount of isotope absorbed by the palms from the various treatments over a fixed time was measured. No difference in the amount of the isotope absorbed was observed.

Physico-chemical properties and compatibility study on palm oil products with cocoa butter

The physico-chemical properties of binary blends of palm oil products with deodorised cocoa butter (DCB, IV 32.7) at levels ranging from 10% to 90% (w/w) were evaluated. Cocoa butter equivalent (CBE, IV 32.4) showed full compatibility with DCB at all concentrations and crystallised to form a strong β in a mixture of β + β’ polymorphic forms. Results of solid fat content (SFC) show that the addition of 10% to 20% palm-mid fraction (PMF, IV 41) and cocoa butter substitute (CBS, IV 0.3) with DCB gave rise to eutectic effects and that the mixture crystallised to form a strong β’ in a mixture of β + β’ polymorphic forms. The differential scanning calorimetry (DSC) melting thermograms of the CBE and DCB blends showed a single melting peak at ± 19.5°C. There were two prominent melting peaks observed in the blends containing more than 10% to 20% of CBS and PMF.

Corrosion of boiler tubes in a palm oil mill

This article investigates the leaking of tubes in a water tube boiler used in a palm oil mill. Leakages were discovered in the roof tubes and the rear wall tubes of the boiler. Samples of the punctured tubes were removed for examination. Micro- and macro-examinations were conducted to determine the causes of failure. EDX/SEM (energy dispersive X-ray spectroscopy/ scanning electron miscroscope) was also conducted to examine the composition of the elements of the specimens and a high concentration of sodium was shown. Key outcomes from the investigation are outlined in this article. They indicate that caustic corrosion was the cause of the leakages of the tubes.

Evaluation of MPOB oil palm germplasm (Elaeis guineensis) populations using EST-SSR

MPOB has initiated an oil palm genetic resources programme which includes the collection, evaluation, utilisation and conservation of oil palm germplasm. The objectives of this study were to determine the potential use of expressed sequence tag-simple sequence repeats (EST-SSR) markers to study the genetic variability of the germplasm collection. A total of 330 palms originating from 11 countries in Africa were screened using 10 EST-SSR primers. The data were analysed using the Biosys-1 software to calculate the genetic variability parameters. It was found that the germplasm exhibited a high level of genetic diversity. Most of the loci tested were 100% polymorphic at 0.95 criterion. A total of 46 alleles were detected across all the germplasm populations. Of these, three were considered as rare alleles. The Nigerian germplasm showed the highest number of alleles per locus and the highest number of rare alleles, a high percentage of polymorphic loci and high heterozygosity, suggesting that Nigeria could be the centre of diversity of the wild oil palm. This study also revealed that the Madagascar germplasm is unique and different compared with the oil palm populations from the African mainland. Based on the dendrogram constructed, the germplasm populations could be divided into three major clusters; Cluster 1 consisting of Angola, Tanzania, Cameroon, Nigeria, Democratic Republic of Congo (formerly known as Zaire), Sierra Leone, Guinea and Ghana germplasm, Cluster 2 consisting of Gambia and Senegal germplasm, while the Madagascar germplasm was placed in Cluster 3. The mean genetic distance across the MPOB germplasm populations was 0.251.

Emission reduction options for peatlands in the Kubu Raya and Pontianak Districts, West Kalimantan, Indonesia

The peatlands of Indonesia are an increasingly important land resource for the livelihood of the people and for economic development, but they turn rapidly into a carbon source when the peat forests are cleared and drained. Therefore, strategies are needed for the sustainable management of the peatlands and to reduce greenhouse gas emissions. This research was conducted on 464 642 ha of peatland varying in depth between 200 and 680 cm, in the districts of Kubu Raya and Pontianak, in the West Kalimantan province of Indonesia. It was aimed at: (i) evaluating land use changes in the peatland of the two districts and assessing the CO2 emissions these entail; and (ii) recommending options for mitigation of the CO2 emissions. Satellite images in the years 1986, 2002 and 2008 were used for the evaluation of land use changes. This was followed by ground-truthing of recent land cover in 2009. Interviews were conducted with stakeholders to develop emission reduction strategies. The results show that the peatlands were used for various purposes, including the traditional slash-and-burn agriculture for maize, pineapple plantations, intensive vegetable farming, and rubber and oil palm plantations. The peat forest area decreased by 16% from 393 000 ha in 1986 to 329 390 ha in 2008, while shrubland increased by 153% from 9427 ha to 23 814 ha over the same period of time. Oil palm plantations and paddy fields also increased rapidly in expansion. The main sources of emissions were from peat burning, especially for the slash-and-burn farming, peat decomposition due to drainage, and the loss of biomass depending on the land use trajectories. Emission reduction can be achieved through various scenarios. Scenario I, confining future agricultural land development to peatland with peat of <3 m thick, is expected to reduce by 6.8±2.9% the 2010 to 2035 cumulative CO2 emissions from the 127 million tonnes ‘business as usual’ (BAU) level. Scenario II, providing fertiliser subsidy to replace the traditional burning technique in addition to Scenario I, is expected to reduce emissions by as much as 11.5±4.9%. Scenario III, switching future agricultural expansion to mineral soils, is expected to lower the cumulative emissions by as much as 20.5±8.8%. These scenarios form the basis for sustainable peatland management and for a state of preparedness to reduce emissions from peatland.

Influence of a lubricant auxiliary from palm oil methyl esters on the performance of palm olein-based fluid

The increasing demand to replace toxic petroleum products with non-toxic renewable sources has driven the use of environmental-friendly lubricating fluids, particularly vegetable oils with modified or enhanced lubricating properties. However, relatively little has been reported on the use of a plant oil-based lubricant auxiliary, e.g. methyl esters, as an oil component for biolubricant manufacturing, and on the resulting lubricating characteristics. Hence, this article investigates the effect of the presence of methyl esters of palm oil (POME) as a lubricant auxiliary on the lubricating characteristics of palm olein-derived base fluids. Palm olein was fortified and homogenised with 1%, 10%, 20%, 30% and 40% POME, and the lubricating performance of each base fluid was compared with that of palm olein. Interestingly, the POME-fortified palm olein-derived base fluids were found comparable to, if not better than, the mother fluid (palm olein) in a couple of the properties studied, and some properties were superior to the required SAE standards/specification for commercial petroleum-based lubricants. The changes in lubricating properties were directly related to the proposed structural linkage of POME to the triglyceride molecules in palm olein.

Fate of thiram in an oil palm nursery during wet season

Thiram (tetramethylthiuram disulfide) is a fungicide used to control plant pathogenic fungi such as Rhizoctonia spp, Phythium spp. and Fusarium spp. which often infest oil palm seedlings from the pre-nursery until the main nursery stage. With increasing applications of thiram in oil palm nurseries, it is necessary to investigate the fate of thiram in the nursery environment. The trial was conducted from July till August 2008, i.e. during the wet season, at the Labu Estate Nursery (Sime Darby), Nilai, Negeri Sembilan. The subplots were treated with thiram at the manufacturer’s recommended dose and at double recommended dose. Thiram residue was detected in the soil at all depths (from 0-50 cm) for both treatment doses on the day of spraying (0 DAT). The amount of residue was observed to decrease with soil depth. Analyses of water and oil palm leaflets within the trial showed that thiram was found at 0 and 3 days after treatment of the trial plots at the recommended and double the recommended doses. The results showed that adsorption and dissipation of thiram were slowly being influenced by the type of soil and the total amount of rain received during the experiment. Run-off and wash-off were the major causes of the loss of thiram residues from the water in the nursery environment and from the leaflets of the oil palm seedlings.

An improved method for the determination of chlorphyrifos in palm oil matrices using gas chromatography

The objective of this study was to improve the method for determining chlorpyrifos, an organophosphorus insecticide, in various palm oil matrices. Chlorpyrifos was separated from the oil matrices using acetonitrile extraction and then subjected to the solid phase extraction (SPE) clean-up process. A silica-based SPE was used for the clean-up process. Quantification of the extracted chlorpyrifos was carried out using a gas chromatograph (GC) equipped with an electron capture detector (ECD). The GC detector response was tested using standard solutions containing 0.005 to 0.12 mg ml-1 of chlorpyrifos. The retention time for chlorpyrifos was 4.8 min with the minimum detection limit at 0.005 mg ml-1. The average recoveries of chlorpyrifos from crude palm oil (CPO) spiked with 0.02, 0.04, 0.06, 0.08 and 0.1 mg ml-1 chlorpyrifos were 94 ± 2.3%, 93 ± 1.4%, 99 ± 1.6%, 97 ± 2.9% and 95 ± 0.7%, respectively. In the case of crude palm kernel oil (CPKO) and refined, bleached, deodorised palm olein (RBDPOo), the recovery of chlorpyrifos from the spiked oil samples containing 0.02 to 0.1 mg ml-1 of chlorpyrifos ranged from 100% to 101% and from 93% to 99%, with the coefficient of variation ranging from 1.3% to 3.0% and from 0.7% to 2.9%, respectively. The method developed was used to determine the chlorpyrifos content in samples of CPO, CPKO and RBDPOo from mills and a refinery in Selangor, Malaysia. No chlorpyrifos residue was detected in any of the CPO, CPKO and RBDPOo samples collected.

Conversion of lignocellulose from oil palm biomass into water-soluble cellulose ether

Cellulose, in combination with lignin and hemicellulose, is found in all plant materials. It is also the most abundant form of plant biomass. In the oil palm industry, empty fruit bunches (EFB), which are generated in large amounts at the palm oil mill, is made up of approximately 37% α-cellulose (on a dry weight basis). The use of this oil palm by-product may be expanded by the chemical modification of the cellulose into products of high value, such as cellulose ether. This study attempted to synthesise water-soluble cellulose ether, particularly sodium carboxymethylcellulose (NaCMC), from the EFB fibre. The properties of EFB-based NaCMC including the degree of substitution (DS), and viscosity were studied. In addition, the a-cellulose and NaCMC were analysed for their structural properties by Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffractometry. The properties of EFB-based NaCMC in comparison to the United States Pharmacopeia (USP) grade NaCMC (from Sigma-Aldrich) were discussed. EFB-based NaCMC exhibited viscosity of about 400 cps (2% at 25°C) while USP grade NaCMC exhibited viscosity of 500 cps (2% at 25°C), i.e. slightly higher than EFB-based NaCMC. The infrared spectrum of a-cellulose from EFB was identical to that of commercial cellulose (from Sigma-Aldrich) with the presence of C-O-C, C-C, O-H and C-H bands. The typical absorption bands observed between 1300 cm-1 and 1580 cm-1 on the infrared spectra for both the EFB-based NaCMC and USP grade NaCMC indicated the presence of the COO group. As for the X-ray diffractogram, the profiles of both the EFB-based NaCMC and USP grade NaCMC were identical, even though the EFB-based NaCMC was less amorphous in structure compared with that the USP grade NaCMC. The results suggest chemical disruption of the cellulose crystallinity by breaking hydrogen bonds in cellulose and opening the structure to accessibility by other chemicals. These findings on NaCMC from an underutilised by-product of the palm oil industry could contribute towards the development of an oil palm-based specialty chemicals industry.

Conventional gel permeation chromatography vs. gel permeation chromatography with combined detectors

Conventional gel permeation chromatography with a single differential refractive index detector (GPC-DRI) and GPC-DRI/viscometry were used to analyse low molecular weight compounds (palm oil and its fractions, polyether polyols, palm oleic acid-based polyols (PolyMo), palm kernel olein-based polyols and commercial palm oil polyols) and high molecular weight palm oil polyols (POP Pioneer, POP Primers Type 1, Type 2 and Type 3, and POP Premier) and commercially available palm oil polyols. The low and high molecular weight samples were analysed using PLgel Mixed E and PLgel Mixed D columns, respectively. Narrow distribution polystyrene with varying molecular weight was used as the standards for normal calibration (GPC-DRI) and universal calibration (GPC-DRI/viscometry). GPC analyses for all of the samples were carried out using tetrahydrofuran stabilised by 5% butylated hydroxytoluene (BHT) as the mobile phase. The flow rate was maintained at 1 ml min-1 with the column oven temperature at 30°C. It was found that in all of the compounds analysed, the peak average molecular weight (Mp), number average molecular weight (Mn) and weight average molecular weight (Mw) obtained using the two methods showed obvious differences. The molecular weight distributions (MWD) of palm-based polyols showed that the modality was similar, but the overlaid MWD from the two different methods showed they were not precisely matched. The results show that the use of conventional GPC with non-matching calibration standards may not give the absolute molecular weight averages and MWD. Due to the unavailability of matching commercial standards, GPC-DRI/viscometry was found to be more suitable for the analyses of palm oil-based polyols because the method relies on universal calibration.

Biochemical studies and purificationof oil palm (Elaeis guineensis Jacq.) β-ketoacyl-acyl-carrier-protein (ACP) synthesis (KAS) II enzyme

The rapid increase in palm oil production over the last 20 years has made this oil the most important in the world. Palm oil produced in the mesocarp of the oil palm (Elaeis guineensis) fruit contains primarily palmitic (44%) and oleic (39%) acids with only a small proportion of polyunsaturated fatty acids. As a prelude to detailed biochemical analysis of the fatty acid biosynthesis of oil palm, we examined β-ketoacyl-ACP synthase (KAS) II activity, and evidence is presented on its importance in palmitic acid accumulation. In this study, three different oil palm breeding materials were screened for KAS II and fatty acid compositions. Collectively, the results strongly suggest that KAS II plays an important role in determining the relative amounts of C16 and C18 fatty acids in oil palm. KAS II activity was profiled through various stages of fruit development from 12 to 22 weeks after anthesis (WAA). The data depicted a pattern of progressive increase in KAS II activity similar to that of triacylglycerol synthesis in the oil palm mesocarp which started at 15 WAA and reached a maximum around 20 WAA. The enzyme was purified to homogeneity (>9000-fold purification) using a combination of ion exchange on CM-Sepharose, HR-DEAE, hyroxyapatite and affinity chromatography (ACP-Sepharose). Activity of the purified enzyme was inhibited by the chelating agent ethylene diamine tetra-acetate (EDTA) (1 M), but the inhibitory action could be overcome by divalent cations such as Mn2+ or Mg2+ (10 mM). Optimal activity was observed at pH 4.5. The data represent the first contribution to the biochemical characterisation of oil palm KAS II activity associated with fatty acid biosynthesis.

Effect of BT products, Lepcon-1, Bafog-1(s) and Ecobac-1(ec), against the oil palm pollinating weevil, elaeidobius kamerunucus, and beneficial insects associated with cassia cobanensis

The effects of Bacillus thuringiensis products, Lepcon-1, Bafog-1 (S) and Ecobac-1 (EC), on the oil palm pollinating weevil, Elaeidobius kamerunicus, and beneficial insects, especially parasitoids, were studied. For pollinating weevils, oil palm male spikelets with weevils were treated by spraying with Lepcon-1 and Ecobac-1 (EC) at five different concentrations, ranging from 5.2 x 107 to 5.2 x 1011 cfu ml-1 for Lepcon-1, and 7.34 x 107 to 7.34 x 1011 cfu ml-1 for Ecobac-1 (EC). For Bafog-1 (S), male spikelets with weevils were fogged at a dose of 7.7 x 1011 cfu ml-1. The Bt products Lepcon-1, Bafog-1 (S) and Ecobac-1 (EC) were safe for E. kamerunicus. Direct spraying of Lepcon-1, Bafog-1 (S) and Ecobac-1 (EC) at the highest concentrations caused 13%, 10% and 11% corrected mortality at nine days after treatment (DAT), respectively. Cypermethrin was toxic to the pollinating weevils as it killed 100% of the weevils at as early as five DAT. Lepcon-1, Bafog-1 (S) and Ecobac-1 (EC) were also harmless to beneficial insects. Application of these products by spraying at the highest concentrations resulted in low mortality of the beneficial insects, ranging from 8% to 13%. Cypermethrin was toxic to the parasitoids as spraying of the chemical at 7.5% w/w killed 100% of the beneficial insects at as early as five DAT. The laboratory study showed that Lepcon-1, Bafog-1 (S) and Ecobac-1 (EC) were safe for the oil palm pollinating weevils and beneficial insects and, therefore, they are recommended for use in the integrated control of bagworms in oil palm.

Mutatition induction using gamma irradiation on oil palm (Elaeis guineensis Jacq.) culutres

This article reports on in vitro mutation induction in oil palm (Elaeis guineensis Jacq.) using gamma irradiation. The radiosensitivity tests were carried out to determine the level of gamma dose suitable for oil palm cultures with good regenerative capacity. Calli from Clone C3-5, Clone GP13-0, Clone GP13-1 and Clone C7-1 were exposed to various levels of gamma radiation (GR) from 0 to the highest 100 Gray (Gy). Of these, embryogenesis was observed in Clone C3-5 and Clone GP13-0 at 40 Gy and at lower doses of GR. The mean weight of callus growth was halved at about 40 Gy to 60 Gy of gamma rays. AFLP analysis was carried out on these callus cultures to monitor changes in the DNA profile. The DNA changes were observed even at a dosage as low as 10 Gy. The changes observed were basically random in nature. For a mutation induction study, leaf derived calli from a selected ortet was used. Friable callus from Clone CX49, Line A’ and Line B’ were exposed to both fractionated and acute irradiation. When fractionated irradiation was used, there were no significant differences in the establishment of polyembryoid cultures and shoot production. In this study, the highest gamma ray dose was 5 Gy repeatedly given for three and five times at 4-5 subculture intervals. Under acute irradiation with doses of 0, 20, 40, 60, 80 and 100 Gy, the embryoid growth decreased significantly at doses of 40 Gy and above, which also affected the shoot regeneration.