Category Archives: 2016 Vol 28 June

EFFECT OF FRYING ON THE PALM OIL QUALITY ATTRIBUTES – A REVIEW –Review Article

Frying is one of the most versatile food processing operations employed since antiquity. The establishment of this process is evidenced by a great consumption of fried food around the globe. Despite palm oil is extensively utilised in various frying applications, the preservation of its quality attributes as a result of thermal processing is still a concern to food processors and consumers. This article, therefore, aims to provide an overview of published studies on the behaviour of palm oil, in their pure form and blended with other oils, during frying at various processing conditions. In this review, publications associated to frying stability of palm-based oils were considered to ascertain a series of oil quality indices – i.e. free fatty acid, smoke point, peroxide and p-anisidine values, vitamin E, induction period, fatty acid composition, colour, and polar and polymer compounds – under prolonged thermal processing conditions. Stability of palmbased oil, however, is not solely dependent to the inherent properties of the oils themselves. Hence, the effects of operating conditions (oil temperature, cooking time, frying duration or cycle, oil replenishment, frying system and cookware materials) and food compositions are also discussed in this article.

RNA FROM FRESH FROZEN CRYOSECTIONS OF OIL PALM INFLORESCENCES IS SUPERIOR TO FFPE SECTIONS

Formalin-fixed, paraffin-embedded (FFPE) and fresh frozen (FF) tissue sections are valuable sources for histology and molecular studies. However, FFPE tissue sections usually provide poor quality RNA that is unsuitable for most downstream molecular applications. In this study, tissue preparation for cryosectioning and RNA extraction protocols were optimised for FF oil palm inflorescences. FF tissue treated with sucrose offered good cellular image resolution and more importantly, good RNA quality. Higher RNA quality with good RIN values (>6) was obtained from FF sections compared to the fragmented RNA from FFPE tissue sections. However, FFPE sections provided better resolution in terms of cellular morphology. The quality of cellular morphology of the FF sections was moderate, but was sufficient to distinguish the different cell types. Hence, FF oil palm inflorescences is a better choice for downstream transcriptomics studies that require tissue sections without compromising the cytological details.

SOIL FUNGAL COMMUNITY ASSOCIATED WITH PEAT IN SARAWAK IDENTIFIED USING 18S rDNA MARKER

Fungi are principal decomposing microorganisms in acidic environment of peatlands. A useful tool for molecular screening of soil fungal communities using the 18S rDNA primer has been proven capable of identifying a broad range of fungi species within Ascomycota, Basidiomycota, Zygomycota and Chytridiomycota. Currently, very little information is available on fungal communities in deep peat of Sarawak, Malaysia. In this study, we have isolated the fungi from soil samples taken in deep peat forests and oil palm cultivated areas. The fungal identity was undertaken using 18S rDNA primer which is EF4-F/ fung5-R. The microscopic structures were conducted to confirm the identity of the isolates. Based on this study, the fungal division most commonly found in deep peat is the Ascomycota. Aspergillus fumigatus was the most common species and more dominant in oil palm cultivated areas and logged-over forest than in primary forest. In the primary forest, the dominant species was the A. flavus, while Hypocrea atroviridis was commonly associated with oil palm cultivated areas and logged-over forest. Other species of fungi isolated in peat primary forests were Penicillium chrysogenum, Trichoderma sp., Phanerochaete sp., Mortierella chlamydospora, A. niger, A. alliaceus, etc. The in-depth difference in the fungal communities for the different sites will be further investigated using the next generation sequencing technology.

EFFECTS OF HIGH CARBON DIOXIDE LEVEL ON THE EMERGENCE OF OIL PALM POLLINATING WEEVIL, Elaeidobius kamerunicus

Elaeidobius kamerunicus is the main pollinating insect of oil palm in Malaysia. The increase of ambient carbon dioxide (CO2) may promote greater crop growth and yield of oil palm. However, E. kamerunicus’ adaptability and survival under high CO2 level are still unknown. An oil palm weevil emergence study was conducted in plant growth chambers with two CO2 levels, 400 ppm and 800 ppm. The plant growth chambers were set at 27°C and 70% relative humidity for the entire study period. Spikelets were taken from apical, middle and basal regions of anthesising male inflorescences from 6-year old DxP palms under normal field conditions. The sampled spikelets were placed in clear plastic tubes with both open ends covered with muslin cloth. The emergence of adults was observed at two-day interval until 10 days after incubation. The total number of weevils which emerged from the spikelets at 400 ppm and 800 ppm CO2 levels were 240 and 233 individuals, respectively. Doubling the ambient CO2 level to 800 ppm had no effect on E. kamerunicus emergence in controlled condition. Further study on oil palm weevil adaptability and survival under high CO2 level is needed to provide information on the effects of future climate change scenario and oil palm yield.

ANALYSIS OF BIOCHEMICAL PROPERTIES RELATED TO HARD BUNCH PHENOMENA IN OIL PALM (Elaeis guineensis Jacq.)

Hard bunch is an abnormal phenomenon occurred on fruits of oil palm. This abnormality exists in several oil palm plantations in Indonesia and typically, hard bunch occurs in areas which are frequently dry. Up to this point, the hard bunch biochemical properties are not well understood and therefore, many researchers are trying to elucidate this abnormality. The objective of this study was to characterise the biochemical properties related to the abnormal oil palm fruits. The fruits samples which were collected from the oil palm plantation in Lampung were subjected to the physical and biochemical properties analysis of the bunches. Analyses performed on the bunch were carotenoids, tocopherol, phenolic acids, lignin and oil extraction ratio. The experimental results indicated that fresh fruit bunch, spikelet weight, total carotene, 4-hydroxybenzoic acid, chlorogenic acid, ferulic acid and lignin of fruit abscission zone observed from normal and hard bunches were significanly different. On the other hand, the other parameters were not significantly different. However, lignin accumulation in the abscission zone which affects the loosenes of fruits from the bunch, indicated high level in the hard bunch abnormality (76.41%) compared to that of normal oil palm (70.61%).

SIMPLE IMPELLER SYSTEMS FOR MAINTENANCE OF OIL PALM CULTURE AGGREGATES

Scaling up of liquid culture systems generally involves moving from the use of simple shake flasks to bioreactors or specialised vessels; this is costly. A new innovation called the Two-in-One MPOB Simple Impeller (2-in-1 MoSLIM) was developed using commonly available Schott bottles in the laboratory. This system provided simultaneous aeration and agitation (two-inone) in a single device for tissue propagation in liquid culture. The 2-in-1 MoSLIM produced cell aggregates with fresh weight increments of two- to six-fold over 30-40 days. This system was a convenient alternative compared to the conventional shake flask system. Multiplication of cultures in the 2-in-1 MoSLIM did not require any shaker or a big space area. This system with a working volume of 300 – 700 ml used a simple impeller and a pump for agitation and aeration purposes. However, with the 2-in-1 MoSLIM, media replenishment remained a tedious task. To overcome this, modifications were made to the system to enable media replenishment on-site without the need of a sterile hood. The adaptation of 2-in-1 MoSLIM with an earlier innovation, Fast Transfer Technique (MoFaTT) in Liquid Culture System, resulted in the development of the Simple Impeller with Fast Transfer Technique (SLIM-FaTT) system. This new system can be applied to the liquid culture system of any crop with a potential towards automation.

MICROBIAL SUCCESSION IN CO-COMPOSTING OF CHIPPED-GROUND OIL PALM FROND AND PALM OIL MILL EFFLUENT

Succession and phylogenetic profile of microbial communities during co-composting of chippedground oil palm frond (CG-OPF) and palm oil mill effluent (POME) were studied by applying polymerase chain reaction-denaturant gel gradient electrophoresis (PCR-DGGE) analysis. The results indicated that the dominant microbial community detected was γ-Probacteria such as Pseudomonas sp. at almost throughout the composting process. Whilst Bacillales such as Bacillus psychrodurans were found toward the end of the composting process. Bacteroidetes such as Pedobacter solani were detected at the final stage of composting. This study contributed to a better understanding of microbial shifting and functioning throughout CG-OPF composting. Therefore, PCR-DGGE is recommended to be used as a tool to identify potential microbes that can contribute to a better performance of composting process.

CHARACTERISATION OF PELLETS MADE FROM OIL PALM RESIDUES IN COSTA RICA

Presently, there are around 67 000 ha of oil palm (Elaeis guineensis) in Costa Rica. The resulting post-harvest residues are not being used currently. These residues can be employed for generation of heat by means of pelletisation. This study evaluates pellets fabricated with empty fruit bunches (EFB) and oil palm fruit mesocarp (OPFM), considering the physical (length, diameter, apparent density and moisture absorption), chemical (C and N content, C/N ratio, cellulose, lignin and extractives), energy (calorific value, ash, volatile and moisture content) and mechanical properties (mechanical durability and force at break) of the pellets, as well as the quality evaluation by means of X-ray densitometry and their efficiency in real conditions of use. Results obtained show few energy, physical and mechanical differences between both types of pellets. The greater differences appear at the chemical level where, in the case of OPFM, high oil or resin contents may be the cause. Both pellets showed density levels within the international ranges, although with internal variations, especially in OPFM. For both types of pellet, it is necessary to improve the combustion process in order to achieve better efficiency, especially with respect to residual mass and O2 emissions.

EFFECTS OF FATTY ACIDS AT DIFFERENT POSITIONS IN THE TRIGLYCERIDES ON CHOLESTEROL LEVELS

Previous studies established a series of regression equations for predicting the risk factor effects from serum cholesterol concentrations. However, the degree of saturation was solely based on total fatty acid composition in triglycerides. Our article is focused on the relationships between the published human nutrition studies and predicted values of serum cholesterol levels based on total fatty acid compositions and at sn-2 position in triglycerides. Twenty-two published human nutrition studies were chosen to assess the effects of palm olein, olive oil, cocoa butter, sunflower seed oil, corn oil, soyabean oil, grapeseed oil, groundnut oil and rice bran oil diets on serum cholesterol levels. There were no statistically significant differences between the predicted values of serum cholesterol levels based on fatty acids at sn-2 position and the published human nutrition studies as proven by the statistical analyses with p values more than 0.05. In contrast, there were statistically significant differences between the predicted values of serum cholesterol levels based on total fatty acids and the published human nutritional studies with p values less than 0.05. Fatty acids at sn-2 position appear to influence the cholesterol levels rather than total fatty acids of the triglyceride.

CONVERSION OF CRUDE GLYCEROL TO 1, 3-PROPANEDIOL BY NEWLY ISOLATED Kluyvera cryocrescens

Biodiesel, an environmental-friendly and renewable fuel, has gained market share and popularity as an alternative to fossil fuel. While expanding its production globally to meet the demand, the production of its principal co-product, crude glycerol which is surplus and under utilised, has affected both the economic and environment. Crude glycerol has limited usage due to the impurities present. It cannot be disposed naturally in the environment and its storage and processing are very costly. Glycerol with its triglyceride backbone serves as a natural metabolite susceptible to microbial degradation into high value-added compounds. In this study, a novel 1,3-PD producing bacterial strain isolated from palm oil mill effluent was used in microbial fermentation of crude glycerol. The strain, identified as Kluyvera cryocrescens NBRC 102467 based on its 16S rRNA sequences, was capable of producing 1,3-PD (5.28 g litre-1) along with by-products, butanol (0.34 g litre-1) and acetone (0.31 g litre-1) after an optimum 48 hr of incubation at 30°C in agitated medium enriched with crude glycerol at 150 rpm. Interestingly, its productivity peaked at the 6 hr reaching 0.28 g litre-1 hr-1 and declined thereafter. In future, this strain has potential to be used in the bioprocess of interest.

PROCESS CONTROL FOR EPOXIDATION OF RBD PALM OLEIN

An epoxidation reaction of different types of feedstock, depending on the iodine values, through percarbonic acid route generally generated different amount of heat. Thus, the heating and cooling temperature of the system and reaction need to be regulated to accommodate production of epoxidised products with oxirane oxygen content (OOC) value nearest to the targeted OOC. Four in situ epoxidation reactions, namely Entry 1-4, utilising formic acid and concentrated hydrogen peroxide, were conducted with continuous control of heating and cooling with real time temperature monitoring. All the reactions gave OOC values of between 3.17%-3.37% determined at the 240th min of the epoxidation process. These values were consistent with the theoretical OOC of 3.41% of refined, bleached and deodorised (RBD) palm olein. The neutralisation, washing and drying processes did not alter the OOC values of all the epoxidised products (EPO) giving final dry EPO of OOC between 3.19%-3.32%. The study revealed that epoxidation reaction of RBD palm olein has to be conducted at temperatures within 30°C to 60°C by suppressing the heat generated from the reaction through efficient heating and cooling system.

EVALUATION ON THE EFFECTS OF CULTURE MEDIUM ON REGENERATION OF OIL PALM PLANTLETS FROM IMMATURE EMBRYOS (IE)

Oil palm (Elaeis guineensis) tissue culture is slow, inefficient and genotype dependent. Therefore, efforts to improve the regeneration system are essential and thereby on-going. Immature embryos (IE) have been reported to be more responsive to in vitro culture as compared to other explant types. The objective of this study is to evaluate the most efficient culture media for the regeneration of whole plants from IE. IE were cultured on three media, namely N6, MY3 and MS +Y3. Initial observation showed that calli were induced as early as two weeks after culture. They started to produce friable calli around three to four months later. IE were shown to respond differently to the tested culture media. This initial result will be useful to identify the most responsive culture media for IE as explant.