Category Archives: 2000 Vol 12 No 1

Differential scanning thermograms of palm oil triglycerides in the presence of diglycerides

The melting and crystallization behaviour of palm oil triglycerides was characterized by differential scanning calorimetry (DSC). The influence that diglycerides have on the melting and cooling behaviour of palm oil is dependent on the concentration and nature of diglycerides. All the diglycerides (PP,PO and OO) and the palm diglyceride mixture (PDG) depressed the melting point of the oil. The 1,2 isomer was more effective than the 1,3 isomer. An excess of 1,3 PP elevated the melting point. The crystallization behaviour is complicated if 1,3 PP is present in high concentrations. All the diglycerides studied can undergo co-crystallization with palm triglycerides, except for 1,3 PP at high concentration.

Studies towards understanding proline accumulation in oil palm (Elaeis guineensis Jacq.) polyembryogenic cultures

Thioproline (a proline analog) at 10 mM induced proline (PRO) accumulation in oil palm polyembryogenic (PE) cultures. However, this treatment eventually killed the cultures, presumably due to some degree of toxicity. PE cultures utilized the exogenous proline (ExoPro) and ornithine (ExoOrn) more efficiently in liquid medium than in solid medium. The Pro accumulating cultures which were treated with ExoPro, ExoOrn, or subjected to low temperature stress returned to normal levels on transfer to normal media and conditions. These reversible changes in cellular Pro concentration are consistent with Pro being readily utilizable and so it can be considered a labile metabolize in oil palm PE cultures.

Valuable minor constituents of commercial red palm olein: carotenoids, vitamin E, ubiquinones and sterols

The important minor constituents of crude palm oil (CPO) – carotenoids, vitamin E, ubiquinones and sterols are also preserved in the commercial red palm olein (CRPo). The average carotene content was found to be about 665 ppm. The high-performance liquid chromatography (HPLC) profile of carotenoids showed that all the 11 types of carotenoids of CPO were preserved in CRPo, a – and b -carotene still constitute about 80% of the total carotenoids. Xanthophylls: dehydro-retinal, x -caroten-dione and b -caroten-5,6-epoxide were also tentatively identified based on their UV spectra and elution order. The vitamin E content was in the range of 717-863 ppm, consisting of a-tocopherol (19%), a -tocotrienol (29%), g -tocotrienol (41%), and d -tocotrienol (10%).The sterol content is in the range of 325-365 ppm consisting of b -sitosterol (59%), campesterol (22%), stigmasterol (17%) and cholesterol (<2.6%). Coenzyme Q10 was detected in CRPo with a concentration range of 18-25 ppm. The fatty acid composition indicates that CRPo has 46.7% monounsaturated, 12.8% polyunsaturated and 40.5% saturated fats.

Soil nutrient dynamics and palm growth performance in relation to residue management practices following replanting of oil palm plantations

The Policy of zero burning practices for replanting of oil palm plantations is currently considered desirable since it avoids air and water pollution and may also enable the development of more economically sustainable practices based on nutrient supply from organic matter management. Under the standard zero burning practices, young palms are planted between widely-spaced windrows of residues from the old stands. This practice maximizes the spatial and temporal uncoupling between the release of nutrients from the decomposing residues and plant uptake. An improved understanding of the spatial and temporal patterns of nutrient release and plant uptake will enable better management of the synchrony between these processes and greater conservation of nutrients. Studies were carried out on the establishment and growth of young palms planted into the palm residues which were chopped, shredded or pulverized without additional inputs of inorganic fertilizer. The preliminary results of palm responses to the techniques established were impressive as a consequence of improving nutrient synchrony and the beneficial effects of organic mulching on soil properties to crop production. It is concluded that these methods of planting and residue management improved the spatial integration of nutrient release and uptake by the rooting systems of young palms. The supply of nutrient requirement that is partly provided by the recycling of biomass can reduce the use of inorganic fertilizers to optimize growth rates of the immature palms. Savings in fertilizers resulting from these practices could reduce the production costs as well as contributing towards environmental conservation.

Decomposition processes and nutrient release patterns of oil palm residues

The decomposition patterns of the oil palm residues were found to show a decreasing remaining of dry matter in the order: leaflets > rachises = trunks > roots. The leaflets reached t50 at sir months, the rachises and trunks at eight months and the roots at 10 months. The decomposition rate constant ‘k’of the oil palm residues ranged from 0.13% to 0.22% day-1 in which the leaflets, rachises, trunks and roots had a value of 0.22%, 0.17%, 0.17% and 0.13% day-1 respectively. The controls regulating decomposition of oil palm residues during the study period have been shown to operate in the rank order: macroclimate > microclimate > resource quality > organisms. Rainfall distribution was the main climatic factor that controlled the moisture content of residual materials and the microclimate within different locations in the residue piles strongly modified the variation in temperature and moisture that affected the rate of decomposition. On the average, most of the oil palm residues were found to decompose within 12-18 months while some of the hardier materials, particularly roots, took much longer than 18 months to decompose. Significant accumulation of light organic carbon fraction on the soil surface will provide and relase nutrients to the soil. Nutrients released from oil palm residues showed different release patterns between residue types and nutrients. The leaflets, rachises, trunks and roots all showed nutrient release in the order: K>Mg=Ca>P>N. The release of nutrients from the residues was relatively quick, especially K, with more than 70% of the nutrients released. Generally, the release and transfer of nutrient to the soil pool occurred within the 18 months period.

Preparation and characterization of adsorbents from oil palm fruit solid wastes

Preparation and characterization of activated carbons from oil palm fruit solid wastes were studied. The effects of activation conditions (CO2 flow rate, activation temperature and retention time) on the characteristics of the activated carbons, namely density, porosity, BET surface area, pore size distribution and surface chemistry were investigated. The optimum conditions for activation were an activation temperature of 800°C and a retention time of 30 min for fibre or 50 min for shell, which gave the maximum BET surface area. Adsorption tests showed that the activated carbons from oil palm fibre and shell could be used as adsorbents for both liquid-phase and gas-phase adsorption.

Performance of Elaeis oleifera from Panama, Costa Rica, Colombia and Honduras in Malaysia

The performance of Elaeis oleifera from Panama, Costa Rica, Colombia and Honduras was evaluated in a trial at PORIM Research Station, Kluang, Johor, Malaysia. FFB yield, bunch components, vegetative traits, fatty acid composition, iodine value (I.V.) and total carotene were analysed. Among the oleifera progenies, the highest fresh fruit bunch (FFB) yield was 101.4 kg palm-1 yr-1, total oil to bunch (TOTB) was highest at 9.0%, height increment rate (HTI) lowest at 4.6 cm yr-1, I.V. highest at 96.7 and total carotene highest at 3455.5 ppm. There were significant differences between the four countries for the yield components: average bunch weight (ABWT), parthenocarpic bunch component: mean fruit weight (MFW), oil to wet mesocarp (OTWM) and oil to bunch (OTB), fertile bunch components: MFW, mean nut weight (MNW) and shell to fruit (STF), vegetative traits: petiole cross section (PCS), rachis length (RL), leaflet length (LL), leaflet width (LW), height (HT) and leaf area (LA), component fatty acids: C14:0, C16:0, C16:1, C18:0, C18:1 and C18:2, I.V. and total carotene.

Synthesis and characterization of ester from dihydroxystearic acid

The esterification of dihydroxystearic acid as a source of hydroxy fatty acid and monohydric fatty alcohols (C8-C18) was successfully carried out. The reaction was done at 180°C in the absence of catalyst and the yield of the ester obtained was 80%-96%. The products were analysed by infrared spectroscopy, and some of their physical properties determined.

Oil palm shell as a source of phenol

Oil palm shell was pyrolysed in an externally heated 5 cm diameter, 30 cm high fluidized-bed fast pyrolysis reactor with nitrogen as the fluidization gas and silica sand as the bed material. The products obtained were liquid oil, solid char and gas. The pyrolysis reactor bed temperature was maintained at 500°C with a fluidization gas flow rate of 1.26 m³ hr-1 because this was found to be the optimum condition for maximum liquid product yield. The maximum liquid product was found to be 58 wt% of dry oil palm shell feed. The liquid was a single-phase product. The liquid was characterized by FT-IR, GC/FID and GC-MS for its detailed chemical composition. From the analyses, the liquid was found to contain a very high concentration of phenol and its derivatives, viz., cresol, catechol, guaiacols, syringol, eugenol: 43.3 wt% of total liquid oil. All these are considered to be very high-value chemicals from the point of view of value and price. Thus, an appropriate separation and extraction method is required to find out how to obtain these chemicals, especially phenol, from the pyrolysis oil.

Gel permeation chromatographic clean-up of organo-phosphorus pesticide in oil matrix

Liquid-liquid partition chromatography is widely used as a clean-up procedure for organophosphorus pesticides from various matrices. However, gel permeation is now increasingly used for multipesticides determination. This investigation evaluated the gel permeation chromatography(GPC) for clean-up of monocrotophos in an oil matrix. The gel used in this study was Bio-Beads SX-3 and the GPC solvent system cyclohexane:ethyl acetate (1:1 v/v). The analyte was determined in a gas chromatograph fitted with a flame photometric detector in the phosphorus mode. Recovery of monocrotophos was 74.3%-101.6% with a standard deviation of 3.409-13.453. The method is used for monitoring monocrotophos in edible oil.

Fatty acyl substituent-induced changes in c-chemical shifts of carbonyl carbons: a tool for structural elucidation in acetylated glucose esters of palm fatty acid

Substituent-induced changes (SIC) in 13C-chemical shifts of carbonyl carbon atoms upon interesterification of glucose pentaacetate (GPA) with fatty acid methyl esters (FAME) of stripped palm kernel oil (SPKO), palm oil (PO) and capric (C10) acid, were used to determine the number and positions of the fatty acid substituents on the pyranosyl ring. Results show that SIC on the ring carbon and ring proton atoms are not always consistent with the molecular structures. But SIC on the carbonyl carbon atoms are however unambiquous and consistent with molecular structures of all the products. The analysis of 13C-chemical shift changes of carbonyl carbon therefore provides a means to determine the number and positions of fatty acyl groups in polyacetylated glucopyranoses

Surface active properties of palm oil with respect to the processing of palm oil

The supernatant sludge from the palm oil mill was determined to be surface active from surface tension measurement. In crude palm oil (CPO)/ sludge supernatant, the interfacial tension was determined to be 3 mN m-1 which is favourable for the formation of oil droplets in the CPO slurry.

The refined oil / water systems have higher interfacial tension compared to the CPO / water system. Depending on whether the CPO is chemically or physically refined, the oil/water interfacial tension differs and can be as high as 25.6mN m-1 and 12.7mN m-1 respectively compared to an interfacial tension of 8.00 mN m-1 in the CPO/water system. The higher interfacial tension value indicates more efficient removel of surface active compounds from the chemically refined oil. This may have great implications in the quality and utilization of palm oil in food processing.

The interfacial tension values of the partially refined oils as sampled from various points of refining were found to increase as the oil is processed. In view of this increase, interfacial tension could possibly be used as a process control parameter in the refining of CPO.

Lecithin and monoglycerides were determined to significantly reduce the interfacial tension at the refined palm oil/ water interface. Some of the common minor constituents found in CPO such as carotene, diglycerides, fatty acids and cholesterol did not show surface activity at the refined palm oil /water interface.

Properties of biosurfactant enzymatically prepared from fructose and palm fatty acid

A biosurfactant has been successfully synthesized from fructose and palm fatty acid distillate (PFAD) with Lipozyme IM as biocatalyst. Analysis of its physical and chemical properties showed that this surfactant had a melting point of 49°C-52.3°C and a hydrophile-lipophile balance (HLP) of 16+. This HLB value is in the range suitable for use in cosmetics, detergents and foods. This surfactant, which was a fructose ester, also reduced the surface tension of water from 74 dynes cm-1 to 38.3 dynes cm-1.

Modelling the effects of ‘haze’ on oil palm productivity and yield

An increasing incidence of atmospheric pollution in the Southeast Asian region leading to substantial reductions in solar radiation has promoted concern over the possible long term effects on oil palm yields. Previous models of oil palm growth and production have emphasized the importance for yield of adequate radiation but effects of reduced radiation on yield are not immediately apparent due to the long time required for bunch morphogenesis, the complexity of the process and the presence of assimilate stores which serve to buffer the palm against periods of adverse conditions.

Because climatic factors other than radiation influence the physiological processes on which productivity is dependent, models were developed to take into account the other main factors, namely, temperature , atmospheric vapour pressure deficit (VPD) and soil water availability . Temperature had only a small effect because variations in mean temperature were small. Soil water availability had a larger influence but VPD was the most important factor influencing yields. A lower VPD, lower temperature and improved soil water supply associated with reduced radiation tended to offset yield reductions due to lower light intensity. Under certain conditions, predicted yields were higher under low or moderate than under high radiation. High radiation was associated with high evapotranspiration (ET) rates and lower rainfall, leading to increasing likelihood of soil water deficits and drought-induced yield reductions.

The results of the modeling exercise are related to palm performance in other regions with contrasting radiation receipts.