Crude palm oil

Processing crude palm oil (contains 500-700 ppm carotenoids) to /1-carotene concentrates [7]. 

Liang et al. (2006) investigated the effect of natural and synthetic antioxidants on oxidative stability of crude and distilled palm oil FAME (PME). Crude palm oil contains minor components such as carotenes and a-toco-pherols that upon transesterification, yields crude PME that exhibit superior oxidative stability (OSI > 25h) compared to distilled PME (OSI - 3.5h), which does not contain minor components. Liang and colleagues therefore endeavored to improve the oxidative stability of distilled PME so that it meets the minimum OSI = 6h as specified in EN 14214 (Anon., 2003b). Natural (a-tocopherol) and synthetic (BHT and TBHQ) antioxidants were investigated in distilled PME. It was discovered that both natural and synthetic antioxidants exhibited beneficial effects on the oxidative stability of distilled PME... 

Crabbe, E., Nolasco-Hipolito, C., Kobayashi, G., Sonomoto, K., and Ishizaki, A. 2001. Biodiesel Production from Crude Palm Oil and Evaluation of Butanol Extraction and Fuel Properties. Proc. Biochem., 37, 65-71. 

Figure 10.4. Production of biodiesel from crude palm oil.

The oil at 60 °C is added to the reactor, followed by the methanol solution of the catalyst. The mixture is stirred for 90 min at 65 ° to 70 °C. During the reaction the glycerol is precipitated out but not separated. After the transesterification the sulfuric acid in methanol is added and stirred for another 3 hours. The methanol is recuperated by evaporation at 65 750 min. Water is added, and the glycerol/water layer is separated off. The biodiesel is washed with water until neutral and dried under vacuum. Thus crude palm oil (CPO) is converted into biodiesel meeting the majority of the E. U. standards (Table 10.1). 

Thermal fractionation technology is most developed in the palm oil industry, where most oils are fractionated before sales. Solids profiles of stearins that have been fractionated from crude palm oil by chilling to different temperatures are shown in Fig. 34.21.118 Thermal fractionation, and double fractionation can be useful tools in obtaining fat fractions with the specific desired characteristics (Fig. 34.22).119... 

Fig. 34.21. Examples of stearins separated from crude palm oil by chill fractionation. (FromTan, B. K and Flingoh, C. H. OH. "PORIM Survey 1979/80 Oleins and Stearins from Malaysian Palm Oil Chemical and Physical Characteristics," PORIMTechnol. Palm Oil Res. Inst. Malaysia, No. 4, 1981. With permission.)...

One of the highest known concentrations of carotenoids occurs in crude palm oil. It contains about 15 to 300 times more retinol equivalent than carrots, green leafy vegetables, and tomatoes. All of the carotenoids in crude palm oil are destroyed by the normal processing and refining operations. Recently, improved gentler processes have been developed that result in a red palm oil that retains most of the carotenoids. The composition of the carotenes in crude palm oil with a total carotene concentration of 673 mg/kg is shown in Table 6-5. 

Crude palm oil used to be the main form of export in the past. With the establishment of refineries especially in Malaysia during the mid-1970s and 1980s, refined palm oil products have replaced the crude as the main form of palm oil export. A wide range of processed or semiprocessed products are exported, and these include the different fractions of processed pahn oil known as palm olein (liquid) and palm stearin (solid). The availability of refineries also led to the production of specialty fats products aimed at the confectionery markets. A similar trend has been seen in the export of pahn kernel oil. Palm kernel oil is a coproduct to palm oil produced at a ratio of 10-13 tons of palm kernel oil for every 100 tons of palm oil. Even the export of refined palm kernel oil has begun to decline as more is being used locally by the oleochemical industry that has been estabhshed in recent years. 

Production cost of crude palm oil is made up of cost of production of fresh fruit bunches (EFB) and the cost to mill the FFB. Refining costs are incurred when crude palm oil undergoes refining to produce processed palm products. 

Milling Cost. After the fresh fruit bunches are harvested they are sent to palm oil mills where the oil is extracted and the nuts separated. The amount of crude palm oil (CPO) obtained from the bunch is in the ratio of 18-24% depending on the planting materials. 

Refining Cost. Crude palm oil can be further processed by refining. Presently, most of the palm products obtained in the market are processed using physical or steam refining. Crude or processed palm products may also undergo fractionation where the solid and the liquid portions are separated. The total cost of refining a ton of palm oil is about 25.92 while the cost of fractionation is about 5.55 per ton. 

Crude palm oil extracted commercially from the fresh fruit bunches contains a small but variable amount of undesirable components and impurities. These include some mesocarp fibers, moismre and insolubles, free fatty acids, phos-phohpids,... 

Two methods, namely physical rehning and chemical rehning, are available for refining crude palm oil. They differ basically in the manner in which the free fatty acids are removed. Physical rehning has become the major processing route because of its cost effectiveness, efficiency, and simple effiuent treatment (39). Both processes are able to produce rehned, bleached, and deodorized (RBD) palm oil of desirable quality and stability suitable for edible purposes (40). The unit operations involved in these two processes and the components removed are shown in Figure 12 and Table 31, respectively. 

Figure 12. Flow diagrams of A) physical refining and (B) chemical refining of crude palm oil.

Refining of Other Palm Products. Beside crude palm oil, crude palm olein, crude palm stearin, cmde kernel oil, crude palm kernel olein, and crude palm kernel stearin can also be refined by either chemical or physical processes described before. The basic unit operations and processing conditions for crude palm olein and stearin are similar to those of palm oil. However, in refining palm kernel products, due to the virtual absence of carotenoids, the earth dosage required in the bleaching stage is lower, usually less than 1.0%. Furthermore, due to the presence of shorter chain (C8-C14) fatty acids, the deodorization temperature required is about 230-250°C. Typical achievable quality of RBD/NBD palm kernel oil is given in Table 34. 

Physical Refining. The by-product in the physical refining of crude palm oil is the pahn fatty acid distillate (PFAD). It is obtained as a condensate of the volatile matters carried over from the deodorizer by the action of the stripping steam. It consists of 80-90% of free fatty acid. It has often been used as a raw material for soap making, feed compounding, and oleochemical feedstock. An important and valuable constituent of PFAD is vitamin E in the form of tocopherols and... 

Oxidation. Oxidation of oils and fats is due to prolonged exposure to air. By virtue of the low polyunsaturated fatty acid content, palm oil is relatively more stable to oxidative deterioration than the polyunsaturated vegetable oils. However, in the presence of trace metals such as iron and copper, excessive oxidation at the olefin bonds of the oleic and linoleic acids can occur, resulting in rancidity. Highly oxidized crude palm oil is known to have poor bleachability and thus requires more bleaching earth and more severe refining conditions, and the final product will likely be of poor stability (44, 45, 68). 

Quality Assurance Measures in Plantation and Milling. Availability of good-quality crude palm oil is a prerequisite for the production of good-quality refined palm oil products. The criteria for good-quality crude palm oil are ... 

DOBI, which is defined as the ratio of the uncorrected absorbance values at 446 nm to that at 269 nm, was introduced as a quality parameter to differentiate the refinability of good- and poor-quality crude palm oil. The relation to quality is DOBI >3, good 2.4-2.9, fair, and <2.3, poor (45, 69).]... 

Processing of Crude Palm Oil. The ultimate aim of the processing of cmde palm oil is to obtain various products such as RBD palm oil, RBD palm olein, or RBD palm stearin that meet the requirement of the end users. An effective and efficient quality assurance program in a processing plant is essential and should consist of the following monitoring activities ... 

Recent research (117) has demonstrated that crude palm oil can be used directly as a fuel to run cars fitted with suitable diesel Elsbett engines. The exhaust fumes from crude palm oil engines were found to be cleaner than those from diesel engines, with essentially no sulfur or nitrogen oxides. It is also cheaper and safer to transport crude palm oil than diesel because of the higher flash point (crude palm oil at 240°C vs. diesel at 52°C). 

Cost is always the main factor that determines large-scale utilization. However, the initial results suggest that the use of crude palm oil as an engine fuel would be 30% more costly compared with petroleum diesel under Malaysian conditions. 

TABLE 53. Fuel Characteristics of Malaysian Diesel, Methyl Esters from Crude Palm Oil and Crude Palm Stearin. 

Red palm oil is the richest source of readily available carotenoids and is, therefore, very useful as a pro-Vitamin A supplement. Crude palm oil contains 500-800 ppm of carotenoids, of which (3-carotene and a-carotene account for about 90% (approximately 2 1 w/w), and lycopene, phytoene, and zeacarotenes are inter alias the remaining carotenoids (60). Other vegetable oils contain much lower levels of carotenoids (<100 ppm), but these are removed during the bleaching step in... 

Diacylglycerols are produced in the fmit palm after harvest. The fruits are required to be processed within 24 hours after the harvest in order to control hydrolysis of the oil in the fruit by lipase. This guideline cannot be followed by all palm oil processors during the peak harvest season. As the trading rule for palm oil allows 5% free fatty acids in crude palm oil and 0.25% free fatty acid in neutralized palm olein (58), there is no incentive for the common palm oil processors in producing oils with lower free fatty acids. Commercially available palm oil and palm... 

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