Category Archives: 2008 Vol 20 Dec

Antioxidantive activity of Malaysian herb extracts in refined, bleached and deodorized palm olein

Malaysian herbs such as curry leaves (Murraya koenigii), kaffir lime leaves (Citrus hystrix), pandan leaves ( Pandanus amaryllifolius) and turmeric leaves (Curcuma longa) are often used as flavourings in Malaysian food. They may contain various phytochemicals, which may act as antioxidants or pro-oxidants. In order to investigate the antioxidant capacity, the extracts of these herbs were subjected to antioxidant tests and analysed for polyphenol content. For the accelerated oxidation study, the ethanolic extracts were added to refined, bleached and deodorized (RBD) palm olein and heated to 180°C for 32 hr. The polyphenol content was observed to be highest in turmeric leaves (116.3 mg g-1 gallic acid equivalents), followed by curry leaves (109.5 mg g-1), kaffir lime leaves (103.2 mg g-1) and pandan leaves (101.8 mg g-1). In the DPPH assay and the linoleic acid model system, the antioxidative activity was highest in turmeric leaves followed by curry leaves, kaffir lime leaves and pandan leaves. However, in heated oil, the highest activity was observed in the sample containing curry leaf and kaffir lime leaf extracts at 0.4% with activities comparable to that of BHT (p<0.05). Based on the oxidative stability index (OSI), each of the herbs was capable of retarding oxidation significantly even at 0.1% compared to BHT (p<0.05). The results of this study suggest that these Malaysian herbs have great potential as heat-stable antioxidants, and could be used as alternatives to existing synthetic antioxidants.

Removal of endosulfan from water using oil palm shell activated carbon and rice husk ash

In this study, the adsorption of endosulfan, a type of pesticide, onto agricultural waste-based adsorbents, namely, oil palm shell activated carbon (PSAC) and rice husk ash (RHA), was investigated. The as-received adsorbents were used for batch α- and β-endosulfan adsorption studies which included kinetics and equilibrium aspects at a constant solution pH of 5 and at a temperature of 25ºC. It was found that removal of β-endosulfan by both adsorbents was significantly more efficient than that of α-endosulfan indicating a high affinity of PSAC and RHA towards β-endosulfan. Interestingly, kinetic equilibrium for β-endosulfan adsorption onto PSAC was achieved after 30 min of contact time with a very high capacity of 418 mg g-1. The adsorption kinetics data fitted the pseudo-second order model well, implying chemisorption was the rate-controlling step. Equilibrium adsorption data for PSAC fit the Freundlich isotherm better than the Langmuir isotherm, suggesting the existence of multi-layer adsorption of endosulfan on a relatively heterogeneous PSAC surface. It was found that PSAC was efficient in removing β-endosulfan from water while it was conversely true for RHA.

Genetic variation among oil palm parent genotypes and their progenies based on microsatellite markers

Knowledge on genetic distances and relationships among breeding materials has a significant impact on crop improvement. Molecular markers are being used increasingly to determine the genetic distance between individuals. In this study, microsatellite markers were used to estimate the genetic distances between selected oil palm parent lines. Microsatellite markers are highly reliable, inherited in codominant fashion whereby heterozygotes and homozygotes are distinguishable, easy to score and can be rapidly produced using PCR technology. Nine microsatellite markers were used to screen selected parent palms (15 duras and 4 pisiferas) and their progenies (16 DxP crosses). Data were scored and analysed using the Biosys-1 software to calculate the genetic distance values. A total of 29 polymorphic bands were generated. The genetic distances between progenies ranged from 0.089 to 0.313. These results indicate that microsatellite markers are powerful tools for studying genetic relationships among DxP progenies. These markers should be further explored to assist oil palm breeding.

Synthesis of palmitic acid-based esters and their effect on the pour point of palm oil methyl esters

The objectives of this research were to synthesis palmitic acid-based esters and to study their effects on the pour point of palm oil methyl esters. Palmitic acid was esterified with six different branched-chain alcohols, namely 2-propanol, 2-butanol, 2-ethyl-1-hexanol, 2-methyl-1-butanol, 2-methyl-1-propanol and 2,2-dimethylpropane-1,3-diol. The purified products were characterized by FT-IR, 1H-NMR and 13C-NMR. The effect of the six synthesized palmitic acid-based esters on palm oil methyl esters (biodiesel) was later evaluated. The compounds under study were isopropyl palmitate (1), sec-butyl palmitate (2), 2-ethylhexyl palmitate (3), 2-methylbutyl palmitate (4), isobutyl palmitate (5) and 2,2-dimethylpropane-1,3-diyl daipalmitate (6). All of the synthesized compounds were miscible in palm oil methyl esters due to similar polarity of the solute and the biodiesel. The blends of the resultant six ester compounds in palm oil methyl esters were evaluated respectively for their effect on pour point property. The 2,2-dimethylpropane-1,3-diyl dipalmitate was able to improve the pour point of palm oil methyl esters from 12°C to 9°C when 5 wt % was added.

CantasTM – a tool for the efficient harvesting of oil palm fresh fruit bunches

The Malaysian Palm Oil Board (MPOB) has developed a motorized cutter popularly known as CantasTM for harvesting fresh fruit bunches (FFB) at less than 4.5 m height. CantasTM is a hand-held cutter powered by a 1.3 hp petrol engine.
Trials carried out on CantasTM revealed that the productivity of the machine was 560 to 750 bunches per day (equivalent to 9.50 to 12.6 t day-1 at a bunch weight of 17 kg). The productivity very much depends on the cropping level, the topography of the estate and the operator’s skills. By comparison, the productivity of manual harvesting (using a conventional sickle) is only 250 to 350 bunches per day (4.20 to 6.00 t day-1). Therefore, the productivity of CantasTM is equivalent to two to three human harvesters. Using CantasTM, the estate would be able to reduce 50% of its labour requirement in the harvesting operation. Another advantage of this cutter is that the terrain or topography of estates does not restrict its usage. Saving on fringe benefits amounts to RM 238 120 per year or RM 29 765 per person due to savings in housing, housing maintenance, levy, electricity and water bills, and medical leave.
As for the economics of the machine, based on the machine cost of RM 4500 per unit plus its operational, repair and maintenance costs, the harvesting cost comes to about RM 22.10 t-1. The cost-effectiveness was calculated at RM 0.70 t-1.

The effect of incorporating palm residues at replanting on phosphate dynamics in an inland soil in Malaysia

The effects of adding approximately 200 mg P kg-1 soil in three different palm residue treatments (pulverized, shredded and partially-burned) at replanting on P fractions were investigated in a field experiment at Kluang, Johor, two and three years after oil palm replanting. The three treatments led to about two- to four-fold increases in the organic P pool over the control. This indicates the importance of biological activity, stimulated by incorporation of palm residues, in the distribution of P fractions. Organic P and microbial P are thought to be the main soil P fractions involved in P cycling in the soil when added through palm residues. The results also suggest that when palm residues were incorporated, the amount of P adsorbed was reduced by 40% to 50% after two years and by 45% to 50%, three years after replanting. Decreasing P sorption together with increasing P desorption in the soil is one important aspect for improving plant P uptake efficiency. Amending the soil with palm residues may supply a greater percentage of residual P to oil palm. Therefore, with incorporation of palm residues, P fertilization probably can be reduced for the two years following replanting.

Water-in-oil emulsion of palm biodiesel

Emulsification technique is one of the most significant approaches to the reduction of pollutant emission of diesel engines. In this research, water-in-oil emulsion of palm biodiesel was prepared by mixing palm biodiesel and water in the presence of emulsifier. For experimental purposes, different types of emulsifiers were screened for their ffectiveness in stabilizing the emulsion system. The results of the experiment showed that the polymeric surfactant was found to be the most suitable emulsifier for palm biodiesel emulsion. It was also found that the stability of the emulsion system was increased by increasing the mixing speed. Even though the preliminary engine test showed significant reduction of nitrogen oxides (NOx) emission, data from this research also showed that the calorific value of the fuel also decreased with the increase of water content in the formulation.