Category Archives: In Press

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.

SELECTION OF OIL PALM MALE PARENTS FOR OPTIMAL PLANTING DENSITY ESTIMATED FROM MATURE CROWN SURFACE

Our study on selecting pisifera male parents aims at determining yield per palm as well as the optimal planting density of the tenera offspring. The data pattern came from dura x pisifera testcrosses, planted at 135 and 160 palms ha-1 in North Sumatra, Indonesia from which the breeding values of 15 pisifera parents of Ghana origin are estimated. Optimal palm densities were assessed from the leaf surface at mature canopy, obtained from the product of number of green leaves with the (asymptotic) maximum leaf area (0.95 L-max), inferred from a logistic growth curve fitted through leaf area values versus palm age. The time to reach the optimum values ranged between 5.5 to 7.9 years after planting. Amount of light under the palms, measured by the vigor of Mucuna cover crop, scored 50 and 67 months after planting (cc-score), considerably varied among pisifera. The clear negative correlation between yield and cc-score reveals that male parents selected for yield during the early years of production may generate tenera offspring palms that are highly lightcompetitive later on. To circumvent this drawback, this study suggests to select pisifera parents for yield per hectare at optimal palm density instead of yield per palm.

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.

INFLUENCE OF POLYGLYCEROL ESTER ADDITIVE ON PALM OIL FRACTIONATION IN RELATION TO THE CRYSTAL SIZE DISTRIBUTION

The effect of polyglycerol ester (PGEmix-8) additive on palm oil fractionation was studied at isothermal temperature of 24°C. Sampling was conducted at 20 min intervals to determine the solid fat content (SFC) of the slurries and the yield and compositions of the olein and stearin fractions. The peak of crystal size distribution was reduced from 100 μm to an average of 70 μm when 0.1% (w/w) to 0.5% (w/w) of PGEmix-8 were added in palm oil. The peak value was further reduced to 35 μm when 0.7% (w/w) additive was used. In spite of this, the SFC of the slurries remained unchanged during the isothermal crystallisation. These results show that PGEmix-8 had influenced the crystal size distribution without affecting the volume of the crystals formed. The fractionation results showed that olein yield increased about 3% to 6% but the triacylglycerol composition of the oleins were comparable with the control. An increase of saturation and a reduction of monounsaturation content in the stearin fractions were observed with increasing PGEmix-8 addition. These results implied that the increase in olein yield was due to less olein entrainment as a result of the more homogeneous and smaller crystals of the palm oil slurries.

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.