Category Archives: 1992 Vol 4 No 1

Making value – added products from palm oil by 1-3 regioselectivity enzymatic interesterification

Work was undertaken with a view to enhancing the commercial and nutritional quality of palm oil and its solid fraction by enzymatic interesterification, catalyzed by 1-3 regioselective lipases in a molten medium.  The main aim are to develop base materials for table or confectionery margarine; and to produce liquid oils for salad-dressing and frying, possibly enriched with essential fatty acids, to meet technological and nutritional requirements.

The biological processing of palm oil and its solid fraction by interesterification in a tubular reactor with a fixed catalyst bed containing Lipozyme offers the advantage of continuous enzymatic transformation which makes for greater flexibility in obtaining products with specific properties.  A study of reaction kinetics showed that transformation was complete after 5 h in the reactor, which corresponded to a flow rate of 3.5 ml per hour.  For a given pair of oils in a defined oil/counter-oil ratio, establishment of kinetics showed that it is possible to manufacture products which all have rheological properties closely linked to the time spent in the reactor. Thus, 1-3 RI of the palm stearin/palm kernel oil (30:70) mixture for 30 min and 3h 30 min led to materials resembling a firm margarine in the first case and a soft margarine in the second case. Interesterification with fluid oils gives either plastic fats or oils virtually fluid at 20°C which could be used as salad oils in hot countries.

Construction of recombinant plasmids harbouring single copy Genomic DNA of oil palm in Escherichia coli

Nuclear DNA was eitrattedfrom destarched leaves of oil palm Elaeis guineensis, varieties tenera, dura and pisifera and from leaves of E. oleifera. The nuclear DNA samples were digested with Pst I restriction endonuclease. It was observed that there is some C-methylation in tenera and E. oleifera but not in pisifera and dura. The presence of C-methylation in tenera was of interest and fragments generated from this digestion were utilized in the construction of the library. Restricted fragments of 0.4 to 1.0kb were obtained by gradient ultracentrifugation in 10%-40% sucrose. These fragments were cloned into pUC19 plasmid vector and transformed into E. coli DH5 a as host. Colony hybridization and dot blot hybridization were carried out on all the clones with labelled nuclear DNA. Seventy six percent of the 250 clones analyzed contained single or low copy sequences and 24% contained repetitive sequences.

A note on the inheritance of albinism in oil palm

Albino seedlings were observed among selfings of oil palm (Elaeis guineensis) collected in Nigeria. Discrete phenotypic classes of pigmented plants and albinos conformed well with Mendelian ratios tested by Yate’s corrected Chi-square. Albinism in the oil palm was found to be controlled by a recessive gene.

Interaction of cocoa butter equivalent component fats in ternary blends

Selected commercial samples of palm mid-fraction (PMF), Borneo tallow (IP) and sal stearin (SLs) were blended in ternary systems. The compatibility of fats in the blends was monitored by measuring the changes in melting points and solid fat content. The results showed that the addition of the third component, IP or SLs, to binary blends of PMF:SLs or PMF:IP respectively, did not eliminate the eutectic behaviours which already existed.

Surface tensions of palm oil, palm olein and palm stearin

The surface tensions of palm oil, palm olein and palm stearin against air were measured using a Kruss Digital Tensiometer. Measurements were carried out from 293.2°K to 453.2°K. Determinations were made on twenty samples of each of the three products and the values obtained were between 33.2 and 22.6 mN/m at 293.2°K and 453.2°K respectively. The surface tensions decrease linearly with increasing temperature.

The effects of season rainfall and cycle of oil palm yield in Malaysia

A statistical model incorporating simultaneously the long-term trend, season, rainfall and lagged yield, appears to give a reasonable explanation of the variations in average oil palm yield as expressed by crude palm oil (CPO) production in Peninsular and in East Malaysia.

Variations in CPO production are noted of 53%-57% due to season, being independent of long-term trend, of 12%-24% due to rainfall and of l0%-20% due to tagged yield effects. The seasonality in oil palm yield, being highly significant at the national level, could be quite independent of rainfall though rainfall has apparently interacted with and modified the seasonality pattern to some extent.

Substantial positive correlations of yield with rainfall at lags of 20-24 and 10-11 months (before harvest) clearly relate to the crucial periods of sex differentiation and inflorescence abortion respectively, the effects of which appear to be quite different as between Peninsular and East Malaysia.

The number of negative correlations between palm yield and rainfall may be of interest. A negative correlation at a lag of six months is indicative of some adverse effects of excessive rainfall on anthesis and pollination; those at lags of 30-36 months are probably related to inflorescence initiation. Negative effects of rainfall are also observed at lags of 0-2 months, indicative of the period of oil synthesis. Some significant negative correlations, particularly at a lag of 13 months, and a possible positive correlation at 17 months, have yet to be explained biologically.

A marked positive yield effect at a tag of 16 months and a moderate correlation at 21 months seem to suggest major yield cycles with such periods.

Palm Oil Abstracts

This article compiles abstracts of articles and papers related to palm oil/ oil palm and other oils and fats, published in journals, books, conference proceedings and other publications.