Category Archives: 2020 Vol 32 March

PRINCIPAL COMPONENT AND CLUSTER ANALYSES ON TANZANIA OIL PALM Elaeis guineensis JACQ. GERMPLASM

Genetic variability in germplasm collection is explored for its role in improving plant breeding strategies. In this study, we assessed the pattern of variation on 15 yield and bunch components in 2191 Elaeis guineensis dura germplasm from 13 populations (TZA01-TZA13) originating from Tanzania and planted in Malaysia in 1990. The data retrieved from the Malaysian Palm Oil Board-Breeding Information System (MPOB-BIS) were standardised prior to principal component analyses (PCA) and cluster analyses (CA) using SAS 9.4. First four principal component (PC) (PC1-PC4) having eigenvalue >1 accounted for 92.33% of the total variability with values 41.94%, 25.09%, 16.35% and 8.95%, respectively. PC1 has largest positive association with oil to dry mesocarp, oil to bunch and oil to wet mesocarp whereas largest negative association with kernel to fruit, kernel yield and kernel to bunch. PC2 is positively associated with mean fresh fruit bunch, mean average bunch weight, oil and kernel yield whereas negatively associated with shell to fruit and fruit to bunch. CA revealed high genetic variability lies within Tanzania germplasm collection. The combination of PCA and CA is a useful tool to select specific populations to establish core collection for better efficiency in oil palm improvement.

VARIATIONS IN FATTY ACID PROFILES, OIL AND MOISTURE CONTENT DURING FRUIT RIPENING IN OIL PALM CROSSES GROWN IN INDIA UNDER SUB-TROPICAL ENVIRONMENT

During fruit ripening, a sequence of physical and chemical transformations takes place in oil palm fruits. The study elucidated variations in fruit weight, oil content in mesocarp and fatty acid profiles during fruit ripening at 12, 14, 16, 18, 20 weeks after anthesis (WAA) of four commercial oil palm crosses viz., United Plantations (UP), Deli x Nigeria (DxN), Palode and Deli x Ghana (DxG) under sub-tropical environment. Fruit weight (5.4 g-10.6 g) and oil content (22.6%-79.9%) in crosses increased from 12-20 WAA. The ideal time of harvest was at 20 WAA, which coincided with highest oil content. The moisture content in mesocarp decreased as fruit ripened. Six fatty acid profiles viz., myristic (0.5%-2.1%), palmitic (31.1%- 45.1%), stearic (2.8%-5.1%), oleic (19.1%-43.1%), linoleic (8.7%-32.4%) and linolenic (0.4%-10.4%) were identified by standardising gas chromatograph parameters. Monounsaturated fatty acids (MUFA) and saturated fatty (SFA) acids increased in all crosses as fruits ripened from 12-20 WAA, while polyunsaturated fatty acids decreased during ripening. Monounsaturated and polyunsaturated fatty acids were highest in DxG cross, indicating its better oil quality. Variations in fatty acid profiles of oil palm crosses can be utilised for developing palms with superior oil quality.

GAS EXCHANGE CHARACTERISTICS AND CHLOROPHYLL PIGMENT OF OIL PALM SEEDLINGS UNDER INFLUENCE OF BIOINOCULANTS

The performance of bioinoculants and chemical fertilisers on net photosynthetic rate (Pn), transpiration rate (E), stomatal conductance (Gs), inter cellular CO2 concentration (Ci), chlorophyll, reducing sugars and total phenols in leaves and total seedling dry matter was assessed in oil palm seedlings grown in nursery for 12 months. Bioinoculants viz. Azotobacter chroococcum, Azospirillum brasilense, Bacillus megaterium, Frateuria aurantia, and Glomus aggregatum were used individually, combindly and integrated with chemical fertilisers. There were significant differences among the treatments used in experiment for various physiological and biochemical characters. Of all the treatments, integrated use of microbial fertilisers with 25% of recommended dose of chemical fertilisers (RDF) has emerged as the best promising treatment in influencing the above mentioned characters. The results of the study clearly indicated that minimal dose of chemical fertilisers (25% RDF) may be required for exploiting the best possible growth benefits from bioinoculants.

CORROSION INHIBITION, ADSORPTION BEHAVIOUR AND THERMODYNAMIC PROPERTIES OF N-CINNAMALIDENE PALMITOHYDRAZIDE ON MILD STEEL IN HYDROCHLORIC ACID SOLUTION

The corrosion inhibitory efficiency of N-cinnamalidene palmitohydrazide (CPH) on mild steel in 1 M hydrochloric acid solution was studied using Tafel polarisation, electrochemical impedance spectroscopy and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). Tafel polarisation analysis showed that the maximum inhibition efficiency (ηTafel%) approached 95% in the presence of 200 mg litre-1 of CPH at 328K. The percentage inhibition efficiency increased with increasing inhibitor concentration and temperature of the test medium. Tafel polarisation study clearly revealed that CPH functions as a mixed-type inhibitor with a predominant anodic control. The adsorption of CPH on mild steel surface obeyed the Langmuir’s adsorption isotherm. The evaluation of the thermodynamic and activation parameters indicated that the adsorption of CPH on the mild steel surface took place spontaneously through both physisorption and chemisorption with Gibbs free energy of adsorption (ΔGºads) values from -34.33 kJ mol-1 to -41.38 kJ mol-1. Impedance spectroscopy analysis showed that corrosion of mild steel in 1 M hydrochloric acid solution was mainly controlled by a charge transfer process and CPH formed a protective film on the metal-solution interface. The protective film was further confirmed by SEM images and the elemental analysis that measured by EDX analysis.

DENSITY AND DIVERSITY OF NOCTURNAL BIRDS IN OIL PALM SMALLHOLDINGS IN PENINSULAR MALAYSIA

Over the past half century, oil palm cultivation has been expanding rapidly throughout many developing countries. Due to its economic importance, large tracts of natural land have been converted into oil palm cultivations and where increasing sightings of nocturnal birds have been made. A survey of nocturnal birds was conducted to assess their density and diversity in the oil palm smallholdings in the Selangor state, Peninsular Malaysia. A total of 90 sampling points were established within three oil palm smallholdings. A total of 1408 individuals of 11 nocturnal bird species were recorded. Based on distance sampling techniques, the density of Spotted Wood-owl (Strix seloputo) was estimated at 7 individuals 100 ha-1, followed by 15 individuals for Sunda Scops-owl (Otus lempiji), five for Barn Owl (Tyto javanica) and 79 for Large-tailed Nightjar (Caprimulgus macrurus) per every 100 ha. The presence of a high density of some nocturnal birds in oil palm smallholdings may be associated with the availability of food source and roosting structure that are linked to habitat heterogeneity in the oil palm smallholdings. Our study highlighted the potential of nocturnal bird species, other than the Barn Owl, as biological control agents in the agricultural areas.

MODELLING HOURLY AIR TEMPERATURE, RELATIVE HUMIDITY AND SOLAR IRRADIANCE OVER SEVERAL MAJOR OIL PALM GROWING AREAS IN MALAYSIA

Hourly values of air temperature, relative humidity and solar irradiance are often not available in most of the oil palm growing areas in Malaysia, thus limiting research in studying how these weather variables affect oil palm growth and yield. Therefore, a study was carried out to determine the accuracy of some selected models to estimate hourly values of these weather variables in six major oil palm growing areas in Malaysia. Using daily maximum and minimum temperatures, hourly air temperature was estimated. Together with mean hourly dew point temperature, the estimated hourly air temperature was used to simulate hourly relative humidity which was subsequently used to estimate hourly total solar irradiance. The mean absolute error, root mean square error and Willmott’s index of agreement within a 24-hr period for air temperature ranged from 0.5°C-0.7°C, 0.6°C-1.0°C and 0.81-0.84, respectively; for relative humidity ranged from 0.8%-1.5%, 1.0%-2.0% and 0.88-0.93, respectively and for total solar irradiance ranged from 83-139 W m-2, 109-178 W m-2 and 0.66-0.75, respectively. These models thus could be used to simulate hourly air temperature, relative humidity and solar irradiance in the six major oil palm growing areas in Malaysia.

SCALE-UP STUDY ON THE SUPERCRITICAL CARBON DIOXIDE STERILISATION OF OIL PALM FRESH FRUIT BUNCH

Existing steam sterilisation method of oil palm fresh fruit bunch (OP-FFB) requires huge quantities of water and about 30%-60% of the water results in palm oil mill effluent (POME). In order to circumvent the perennial POME generation problem, it requires a waterless sterilisation system of OP-FFB. The present study was conducted to determine the sterilisation efficiency of OP-FFB using a pilot scale supercritical carbon dioxide (SC-CO2) technology. The sterilisation efficiency was evaluated based on the inactivation of Bacillus spp. and Aspergillus spp. in OP-FFB with varying SC-CO2 pressure (10-30 MPa), temperature (40°C-80°C) and treatment time (15-90 min). Complete inactivation of the microorganisms in OP-FFB was obtained after 45-90 min at treatment range of 10-30 MPa and 40°C-80°C. The findings of the present study reveal that the SC-CO2 sterilisation is a conceivable technology to be used in OP-FFB sterilisation, replacing the current water steam sterilisation technology.

CHARACTERISATION OF PHYSICO-CHEMICAL AND ANTIOXIDANT PROPERTIES OF OIL PALM TRUNK SAPS AS AFFECTED BY THE STORAGE TIME IN COMPARISON TO NIPA SAP

In this study, freshly squeezed oil palm trunk sap (OPT0sap) and sap of oil palm trunk that had been stored for 60 days (OPT60sap) were characterised and compared with a nipa sap (Nsap) as a control sample in terms of their physico-chemical and functional properties. The results indicated that when the two OPT saps were compared, trunk storage significantly impacted the latter sap’s composition. As the storage period increased, the sap became darker and its sugar content increased. Further, the OPT saps showed significant amounts of antioxidant contents, with greater nutritional value compared to Nsap. The OPT0sap’s viscosity was found to be the lowest, whereas the Nsap’s was the highest, with values of 0.87 ± 0.07 mPa.s and 3.77 ± 0.09 mPa.s, respectively. The OPT0sap had the lowest pH, whereas Nsap had the highest. In conclusion, in comparison to Nsap, the OPT saps demonstrated better features in terms of antioxidant capacity and higher reducing sugar content. However, OPT saps had greater acidity and darker colour.

DECOLOURISATION OF PALM OIL MILL EFFLUENT (POME) TREATMENT TECHNOLOGIES: A REVIEW

Since last decade, global demand for edible oil is growing resulting in a remarkable increase in the areas under oil crop cultivation. The Malaysian palm oil industry is one of the largest palm oil producers in the world. In processing palm oil, high volume of liquid waste known as palm oil mill effluent (POME) is generated. The increasing demands of crude palm oil has resulted in the enormous increase of the number of palm oil mills in Malaysia contributing to large amount of POME. Currently, treatment technologies of POME gain a lot of attention in order to meet the standard discharge limits. The colour of POME, which previously was not an issue, is recently being highlighted and it will be incorporated in the regulation soon. Thus, this article provides review on colourants in POME and its possible decolourisation treatments. The possible decolourisation technologies that will be highlighted in this article are adsorption, coagulation and flocculation, membrane technology, microbial treatment, photocatalysis, etc. including their potential in POME colour removal efficiency.

ALTERATION IN COLOUR AND FUNGAL RESISTANCE OF THERMALLY TREATED OIL PALM TRUNK AND RUBBERWOOD PARTICLEBOARD USING PALM OIL

Urea formaldehyde-bonded particleboard made from oil palm trunk (OPT) and rubberwood (RW) were soaked in palm oil for 24 hr before thermally treated in oven at 180°C, 200°C and 220°C. Colour changes and decay resistance against white rot fungus (Pycnoporus sanguineus) of the samples after thermal treatment were investigated. After thermal treatment, Lightness (L*) of the samples decreased and the extent of darkening increased along with increasing treatment temperature. Generally, RW samples became redder after heat treatment while OPT samples basically showed the same pattern except it became greener when treated at 220°C. Yellowing (positive b* value) was observed at milder temperature and succeeded by bluing at higher temperature. Improvement in fungal resistance was observed for both OPT and RW samples. The weight loss of the untreated OPT and RW samples were 12.97 ± 1.62% and 30.71 ± 1.75%, respectively. At 220°C, the respective weight loss of OPT and RW samples were 4.58 ± 0.44% and 5.78 ± 1.23%. RW showed lower fungal resistance compared to that of the OPT. Strong correlations (R2 > 0.75) were found between weight loss and ΔE* suggested that fungal resistance increased along with increasing ΔE* values.

PRODUCTION OF PALM-BASED GLYCOL ESTER VIA AUTOCATALYTIC ESTERIFICATION

The self-esterification of the lauric acid (LA) with diethylene glycol (DEG) to produce diethylene glycol dilaurate (DEG-DL) was conducted under atmospheric via conventional method. The effects of reaction temperature, reactant molar ratio and stirring speed rate were studied. Results showed that the composition of DEG-DL was increased with the increase in reaction temperature and reactant molar ratio. The reaction rate was observed independent of stirring speed rate. A high conversion of LA (>90%) was obtained based on one-factor-at-time (OFAT) method of designing experiments. At the reaction temperature of 230°C and molar ratio of LA: DEG was varied from 1:1 to 2:1, the composition of DEG-DL was increased from 50.1% to 97.2%. Nuclear magnetic resonance (NMR) spectra confirmed a compound produced was DEG-DL based on structural result. The acid value of LA was reduced from 182 to 3.09 mg KOH g-1 LA. The autocatalytic esterification is a clean reaction as it omits the separation step of catalyst and solvents. The hydrophilic lipophilic balance (HLB) index calculated for DEG-DL was 7.5 and potentially functioned as a water-in-oil or oil-in-water emulsifier for cosmetic applications.

COMPARATIVE ASSESSMENT OF THERMAL RESISTANCE OF PALM STEARIN AND HIGH OLEIC BLENDED OIL WHEN SUBJECTED TO FRYING PRACTICE IN FAST FOOD RESTAURANTS

In this study, the thermal stability of palm frying oil (palm stearin, POs) and a formulated high oleic frying oil (high oleic blended oil, HOBO) in China was evaluated under simulated frying protocol in fast food restaurants. A series of physico-chemical properties of the oils were measured including change of colour, acid value (AV), peroxide value (PV), p-anisidine value (p-AV), total oxidation (TOTOX=2PV+p-AV), fatty acids composition (FAC), iodine value (IV), carbonyl group value (CGV), total polar compounds (TPC), oxidative stability index (OSI) and vitamin E content. The frying experiments were conducted at 170 ± 5°C for five consecutive days where French fries were fried in five cycles hourly for 12 hr a day. The results indicated that POs gave higher physical and chemical stability than HOBO under extended frying conditions, considering its relatively lower increase in TPC, p-AV, TOTOX and CGV, lesser decrease in C18:2/C16:0 and IV, and longer induction period. Based on the results, it can be conjectured that POs is a more preferred choice for deep fat frying with lower deterioration rate.

ARE CHARACTERISTICS OF SOFT PALM STEARINS SIMILAR TO SOFT PALM MID FRACTIONS?

The aim of this assessment was to determine the variation between soft palm mid fractions (sPMF) and soft palm stearins (sPOs) which are the co-fractions (solid fractions) obtained from two different fractionation processes which yield palm olein of iodine value (IV) 60. The sPMF and sPOs are not governed by any official standard specifications and are traded based on contractual specifications. Furthermore, the physical and chemical characteristics of sPOs lack documentation as it falls into the general category of palm stearin. Hence, users who are unaware of the differences between these two fractions are misinformed and misguided, leading to dysfunctional application of these fractions in food products. This assessment of sPMF and sPOs evaluated the triacylglycerol composition, fatty acid compositions (FAC), IV, dropping point (DP), solid fat content (SFC) profiles and thermal behaviours in order to establish parameters which can be used as quality qualifiers, which are able to distinctively discriminate both fractions. The triacylglycerol compositions differed significantly between sPMF and sPOs. sPMF contained high amounts of monounsaturated triacylglycerols ranging from 61.83% to 80.07% with 1,3-dipalmitoyl-2-oleoyl-glycerol (POP) ranging from 43.53% to 55.95%. Lesser amount of monounsaturated triacylglycerols were present in sPOs, ranging from 55.56% to 57.33% (POP from 38.36% to 41.81%). The trisaturated triacylglycerols ranged from 2.45% to 5.41% in sPMF and higher values were detected in sPOs ranging from 10.46% to 18.52%. SFC profiles of sPMF and sPOs varied significantly. The sPMF exhibited a sharp decrease in the percentage of solids from 20°C to 30°C which were not exhibited by sPOs. The DP of sPMF ranged between 24.3°C to 31.8°C and sPOs varied between 40.3°C to 50.1°C. sPMF and sPOs exhibit unique and distinctive crystallisation and melting profiles which can be used to differentiate these two fractions. Fatty acid composition and iodine values exhibited overlapping values, hence, are inadequate indicators to differentiate these fractions. The assessment concludes that triacylglycerol composition, DP, SFC profile and thermal behaviour (crystallisation and melting) are indicative parameters that are able to assist in differentiating the physical and chemical characteristics of sPMF and sPOs.

SCREENING OF ORGANOGELATORS FOR STRUCTURING PALM SUPEROLEIN

The study was conducted to investigate the potential of several organogelators in structuring palm superolein such as polyglycerol behenic acid ester (PBAE), sunflower wax (SFW), fully hydrogenated palm-based monoacylglycerols, hard stearin and fully hydrogenated palm stearin. A simple inverted vial approach was used to observe the stability of the oleogels for 90 days at 15°C, 20°C and 25°C. The results indicated that at least 8% (w/w) of fully hydrogenated palm-based monoacylglycerols was needed to form stable oleogels at all storage temperatures. For the hard stearin and fully hydrogenated palm stearin, 10% (w/w) was still insufficient to structure the superolein at 20°C and 25°C. In contrast, only 1% (w/w) of PBAE and SFW gelators were needed to form stable gels that lasted for 90 days at 15°C and 20°C. The effectiveness of these gelators in structuring the superolein mainly relied on their solubility in the oil. The hard palm stearin and fully hydrogenated palm stearin were very much less effective to form superolein gel as compared to PBAE and SFW gelators due to their relatively higher solubility in the superolein. Therefore, these gelators were withdrawn from further investigation.

ASSESSMENT OF SOCIAL RETURN ON INVESTMENT FROM THE UTILISATION OF OIL PALM’S RESIDUES

This study aimed to investigate utilisation of residues from oil palm in local communities and to assess the social return on investment (SROI) from this utilisation. Data collection was undertaken in Thailand through interviews with policy-makers, practitioners, professionals from oil palm cooperatives, the Oil Palm Research and Development Centre, the Department of Agriculture, the Office of Agricultural Economics, and the Federation of Thai Industries. Questionnaires were given to oil palm growers in eight provinces, totalling 80 samples. Interviews were conducted with five palm oil mills. The SROI for various methods of the utilisation was calculated. The results showed that many options for utilisation included tillage, chopping up and letting residues be digested, using empty fruit bunches for mulching, producing biomass energy, mushroom cultivation, and for use as animal feed and compost. As for the SROI of utilisation of oil palm residues, it was found to be between 0.35 and 2.86. The majority of the utilisation options yielded an SROI lower than 1. The utilisation of oil palm residues to produce animal feed yielded the highest SROI of 2.89, whereas the use of oil palm residues to produce hard fibreboard resulted in the lowest SROI at 0.35.

POTASSIUM NUTRITION IN THE OIL PALM: A MOLECULAR PERSPECTIVE

Potassium (K+) is a major nutrient essential for plant growth and development. Acquisition of this vital element and maintenance of K+ homeostasis are complex processes, facilitated by an array of membrane transporters including carriers and channels. Key mediators of K+ uptake are the K+ Transporters (KT) /K+ Uptake Permease (KUP)/ High Affinity K+ (HAK) family of transporters. The oil palm (Elaeis guineensis), is an agriculturally and economically important crop, but the molecular mechanisms of nutrient acquisition in this plant are poorly understood. Here we report the first molecular characterisation of potassium transporters from KT/KUP/HAK superfamily in the oil palm, named EgKUP3, EgKUP8 and EgKUP11.