Category Archives: 2004 Vol 16 No 2

Transesterification of palm oil : effect of reaction parameters

The most practical and suitable method for industrial production of methyl esters of palm oils with negligible free fatty acids (e.g. neutralized palm oil and refined, bleached and deodorized palm oil) is methanolysis of the glycerides catalyzed by sodium hydroxide. Several parts including the type of catalyst, oil/alcohol ratio, temperature, stirring speed and free fatty acids content, have been found to influence the transesterification of palm oil. Optimum reaction conditions were obtained with a molar ratio of methanol-to-oil at 10:1 and a reaction time of 7 min at ca. 65½C. The rate of reaction was optimized at a stirring speed of 150 rpm. The minimum amount of methanol required to achieve total conversion was 233% (excess methanol) (a methanol-to-oil molar ratio of 10:1). The catalyst used should not exceed 0.5 mole kg-1 oil as otherwise it would cause solidification of the reaction mixture due to soap formation. For a large number of glyceride oils containing <5% free fatty acids, transesterification to methyl esters can be readily effected using additional sodium hydroxide to neutralize the free fatty acids. Glycerol from the transesterification process was purified from 80%-85% to more than 96% with a yield of not less than 75%

Selection for partial resistance in oil palm progenies to Ganoderma basal stem rot

The development of Elaeis guineensis progenies resistant to Ganoderma may provide the ideal long-term solution to basal stem rot, a major disease of oil palm in Malaysia and Indonesia. A study was conducted to select different oil palm progenies for resistance to G. boninense infection. In this study, 12-month-old seedlings from 23 progenies, namely, three DxD, six DxP, three OxO, one OxP, five TxP and five TxT were inoculated with G. boninense using the root inoculation technique. External foliar symptoms developing on seedlings were recorded for a period of 12 months. Twelve months after inoculation, all the seedlings were examined for internal symptoms based on the length of inoculated root lesioned, number of primary roots infected and extent of stem bulb tissues lesioned. Based on reisolation of G. boninense from inoculated seedlings, it was shown that all 23 progenies from the different oil palm crosses were infected by G. boninense. The uninoculated seedlings for each of progenies did not show any signs of disease symptoms or lesions and G. boninense was not present. Some 25.6% of the inoculated seedlings were dead due to G. boninense infection, and there were significant differences between the progenies tested for the severity of foliar symptoms measured. For internal symptoms, there was no significant difference in the length of inoculated roots lesioned. However, the number of primary roots infected and extent of stem bulb tissues lesioned were significantly different. Of the 23 progenies, the most susceptible progeny was PK 2724 [DxD, Deli (Elmina) x Deli (Elmina)], whilst a partially resistant progeny was PK 2567 (DxP, Congo x Cameroon). Partial resistance is expressed by low severity of foliar symptoms and slow progress of Ganoderma infection in the roots and stem tissues

Kinetics study on transesterification of palm oil

The kinetics of base-catalyzed transesterification of palm oil based on parameters such as oil and alcohol ratio, catalyst concentration and temperature were investigated to optimize the conversion rate. Our findings showed that both sodium hydroxide and sodium methoxide had high kinetic constants depicting fast formation of palm oil methyl esters with conversions above 99%. Fast formation of palm oil methyl esters with a rate constant of 0.163 litre mole min -1 was obtained when the reaction parameters were: molar ratio of oil to methanol, 1:10; catalyst concentration, 0.125 mole kg -1 oil; and temperature, 60½C

Optimization of the sweep co-distillation clean-up method for the determination of organochlorine pesticide residues in palm oil

The optimum conditions were developed for the quantitative recovery of organochlorine pesticide residues in palm oil using a commercial sweep co-distillation apparatus. Under the optimum conditions (245oC distillation temperature, 250 ml min -1 nitrogen flow rate, 45 min sweep time) and using a trap packed with sodium sulphate and partially deactivated Florisil, the recoveries of 14 organochlorine pesticide residues at ppm and ppb levels in a spiked oil matrix were> 80%, with coefficients of variation ranging from 5.6% – 9.9%. However, the recovery for endrin ketone was below 80% with a coefficient of variation of 8.5%. The cleaned-up extracts were quantified by gas chromatography using a micro-electron capture detector with a fused silica capillary column containing a non-polar bonded phase.

Synthesis of 2-substituted 4(R)-hydroxy-2-cyclopenten-1-one, a prostaglandin intermediate with methyl oleate from palm oil

Methyl oleate, 1 was obtained from palm methyl esters through removal of saturated esters in a urea complex formation followed by silver nitrate impregnated silica gel column chromatography. The oleate was then reacted with 2,3-O-isopropylidene-D-glyceraldehyde 2, to form an aldol compound which, after lactonization, formation of tosylate and cyclic cyanohydrin, and oxidation of the double bond afforded 2-(6–carbomethoxyhexyl)-4(R)-hydroxy-2-cyclopenten-1-one 11, a prostaglandin intermediate

Multiplication of oil palm suspension cultures in a bench-top (2-litr) bioreactor

Oil palm Elaeis guineensis suspension cultures were multiplied in a B-Braun Biostat® B’ 2L version 1.0 bioreactor. An initial experiment using the original system was not successful as most of the culture aggregates lodged between the baffle cage and inner wall of the vessel and also between the blades of the impeller. This damaged the aggregates. Some modifications were then made to the bioreactor by replacing the impeller, baffle cage and microsparger. After modification, the cultures showed good proliferation with about 10- to 14- fold weight increment after 50 to 80 days. Thus, the B-Braun bioreactor with slight modification has the potential for large scale multiplication of oil palm suspension cultures

Life cycle of Sycanus dichotomus (Hemiptera: pentatomidae) – a common predator of bagworm in oil palm

The life cycle of Sycanus dichotomus (Hemiptera: Reduviidae) was studied with two types of prey, Corcyra cephalonicaand Plutella xylostella in a controlled environment room. The eggs hatched after 11 to 39 days with each cluster having 15 to 119 eggs. Five nymphal stages were recorded. The mean longevity of each nymphal stage was 24.35, 16.95, 20.35, 25.32 and 43.51 days when fed with C. cephalonica and 16.72, 15.78, 14.88, 24.03 and 46.84 days when fed with P. xylostella. The period of development from eggs to adult when fed with C. cephalonica and P. xylostella were 193.44 ± 2.41 and 203.91 ± 2.77 days. The mean longevity for male and female adults fed with P. xylostella was 83.47± 4.37 and 87.64 ± 3.31days respectively. The longevity of male and female adults fed with C. cephalonica was 63.99 ± 2.92 and 61.61.86 ± 2.96 days. Lower mortality was recorded on the S. dichotomus fed with P. xylostella.

Degumming and bleaching: effect on selected constituents of palm oil

Degumming and bleaching are essential processes in palm oil refining. The purpose is the removal of gums, trace metals, pigments, peroxides, oxidation products and other breakdown products in the crude oil by adsorption on the active surface of the bleaching earth to improve colour and stability of the final oil. This paper aims to study the effect of degumming and bleaching using neutral and acid-activated clays to achieve the aforementioned objectives. It was found that valuable palm minor components, i.e. [tocols (tocopherol and tocotrienols) were retained; no significant changes occurred in the total phytosterols, squalene, composition of acylglycerols (i.e. mono-, di- and triacylglycerols)] and free fatty acids by using both acid-activated and neutral clays up to 1.0%. However, acid-activated clay reduced the carotenes content. Both clays gave markedly improved oxidative stability with induction period >30 hr at 120 oC. Impurities such as pro-oxidant iron, copper and phosphorus were reduced by both clays. The bleaching effect of neutral clay was relatively poor compared to acid-activated clay in the removal of unwanted compounds.

Immigration and activity of Oryctes rhinoceros within a small oil palm replanting area

The pheromone of the rhinoceros beetle (Oryctes rhinoceros) has been used for mass trapping and monitoring, integrated with biological control agents. In the current study, pheromone traps were used to monitor the immigration and activity pattern of Oryctes adults within a 4.5 ha replanting block. Trapping was initiated after about five months of replanting, for a period of 24 months. The relationships of the trap captures with the heap population, palm damage, rainfall and moon phases were also studied. Infestation of the block occurred almost simultaneously with replanting. The core region of the block was infested between the fourth to seventh month after completion of felling and chipping. It was noted that female beetles were trapped consistently more at the fringes than in the core of the replanting block. There was a significant relationship between the number of adult females trapped (at about 40-60 days before monitoring the population in the heaps) and the number of second instar larvae. There was an increase in the flight activity of the beetle (based on trap captures) during wet weather, likely due to their search for moist breeding sites. Male beetles were more active during the full moon, likely navigating for food and searching for suitable habitats before mating. Cumulative captures of each individual trap and the damage levels of adjacent palms were significantly related. A high proportion (92%) of females captured in the traps were gravid, with a mean of 16 eggs per female. Based on trap captures, there were indications that adult populations were coming from the adjacent mature plantings. This information can be exploited for more effective and targeted control of the pest.

The effects of oils on germination of Beauveria bassiana (Balsamo) vuillemin and its infection against the oil palm bagworm, Metisa plana (Walker)

This study reports the effects of oils on the conidial germination of four strains of Beauveria bassiana (Balsamo) Vuillemin (F1, F5, F8 and F10) and their infectivity against the larvae of the oil palm bagworm, Metisa plana Walker. The effects of the oils and age of the conidia on the germination of the conidia were examined in the first experiment. Of the five oils tested, soyabean oil and paraffin gave the highest germination for both two- and four-week-old conidia. Palm and corn oils completely inhibited the conidial germination. Germination was influenced by the age of conidia with the mature conidia germinating better than the younger conidia. The pathogenicity of all the four strains of B. bassianaconidia formulated in soyabean oil against the larvae of M. plana revealed that more than 95% mortality at 10 days after treatment. Although Strain F5 produced the lowest LT50 (2.6 days), based on the mortality rate and percentage infection, Strain F10 was the more pathogenic. The short (254 nm) ultraviolet radiation was more detrimental to the conidia compared to the long (365 nm) ultraviolet radiation. Soyabean and paraffin oils gave a similar level of protection to the conidia but oil with 1% (w/v) sunscreen gave significantly better protection. Strain F10 was more stable than Strain F5 to both wavelengths of ultraviolet radiation. B. bassiana conidia formulated in oil plus 1% sunscreen and oil alone caused about 12 and 15 times higher mortality against the larvae of M. plana than the water formulation. The advantages of using oil over water for the formulation of B. bassiana to control M. plana in the field are discussed

Seasonal variation in yield and developmental processes in an oil palm density trial on a peat soil: 1. Yield and bunch number components

Short-term changes in bunch weight were found to contribute to seasonal yield cycles in an oil palm density trial on a peat soil in Perak, West Malaysia. Unusually, the cycle in bunch weight was in phase with that in bunch number. The results of bunch analyses carried out over a 10-year period were examined to identify whether cycles also occurred in bunch components and to examine the effects on oil and kernel yields. The analysis showed that total fruit weight per bunch fluctuated more than the weight of the bunch frame, while within the fruit, the mesocarp showed a greater variation in weight per bunch than the nut. However, while the seasonal changes in fruit-to-bunch (F/B) on a mean monthly basis over years were significant, there were no comparable significant changes in the other bunch component ratios.

There was some evidence based on changes in single fruit weight and fruit number that the changes in F/B might be due to variation in pollination efficiency.

The variation in mesocarp weight per bunch was attributable to variation in both the oil and water contents with little change in the fibre. Similarly, within the nut, the larger shell component tended to vary more than the kernel.

The contribution of bunch weight variation to the variation in total yield and its relationship to bunch number are discussed.

Seasonal variation in yield and developmental processes in an oil palm density trial on a peat soil: 2. Bunch weight components

Bunch production in an oil palm density trial on a peat soil in Perak, West Malaysia, displayed a regular annual cycle that was highly synchronized across densities. The phase of the cycle differed from that displayed for West Malaysia as a whole but resembled those at some other sites. Annual cycles were found in both bunch number and mean bunch weight and in the proportion of palms that yielded bunches in any one month. While the long-term trends in bunch numbers and single bunch weights were negatively correlated, in the short-term there was a highly significant positive correlation between the two.

The variation in mean bunch weight was also reflected in the variation in the main bunch components. There were also seasonal variations in the ratios of bunch components.

In addition to yield, regular annual cycles were also apparent in the rates of frond emission, male and female inflorescence production and sex ratio, and in inflorescence abortion. While the phases of bunch and female inflorescence cycles could be matched using physiologically meaningful lag periods, the cycles of frond emission and total inflorescence production, and of frond emission and female inflorescence production could not, giving rise to non-significant or negative correlations.

Abortion rates were low throughout the trial and while a regular sex ratio cycle became apparent from the eighth year, this was not the main determinant of bunch number cycling. Rather, variation in the rates of inflorescence development may be the crucial factor in causing the yield cycles. Other external and internal factors that might contribute to the yield cycles are discussed

Selecting the ideal oil palm: what you see is not necessarily what you get!

Yield is the most important selection trait for the ideal plant. Yield selection on single plants from segregating populations in the early selection cycle is unreliable because of unstable genotypes, low heritability and differential plant competitive abilities. Yield selection is best done in later cycles when sufficient quantities of the selected stable genotypes are available for replicated larger plot yield trials conducted over different locations and agronomic treatments. Breeding progress for yield in major crops has been generally slow at 1% -2% per year but nevertheless significant. Methods, e.g. breeding, physiological, biotechnological, to improve selection efficiency and shorten the selection cycles are not likely to substantially reduce the cultivar development time because of the mandatory extended cycles of yield testing. A smaller erect canopied palm with high harvest index that can tolerate higher density planting would be the oil palm ideotype for efficient yield enhancement. Such cultivars are unlikely to be available for the next 15 years. Nevertheless, plantations should accelerate replanting as improved cultivars particularly with better oil content are continuously being produced, and coupled with the simultaneous implementation of improved agro-management practices, larger quantum yields can be achieved. Existing planted materials already have high genetic yield potential, and the onus lies with the agronomist and manager to implement the prescribed agro-management practices to achieve the yield potential of the site and thus, narrow the gap between potential and realized yields.