Coconut Oil
| Infobox on Coconut Oil | |
|---|---|
| Example of Coconut Oil |  |
| Facts | |
| Origin | Chiefly Philippines and Indonesia |
| Stowage factor (in m3/t) |
|
| Humidity / moisture | - |
| Ventilation | - |
| Risk factors | See text |
Coconut Oil
Description
Bulk Coconut oil is produced by crushing copra, the dried 'meat ‘of the coconut. The principal producer and exporter of coconut oil is the Philippines, which exports large quantities of the oil to North America and Europe. Smaller quantities of the oil are also exported by Indonesia as well as other countries. Coconut oil is in many respects similar to palmkernel oil, the two oils being the most important members of the oils referred to collectively as the 'lauric' oils. Coconutoil is semi-solid at ambient temperature, is very light in colour and has a density of approximately 890 kg/ m3 at 60°C (920 kg/m3 at 15°C). The oil is normally exported in the form of the Crude Oil with a maximum free fatty acid content of 5%, calculated as lauric acid.
Dry process
Coconut oil can be extracted through "dry" or "wet" processing. Dry processing requires the meat to be extracted from the shell and dried using fire, sunlight, or kilns to create copra. The copra is pressed or dissolved with solvents, producing the coconut oil and a high-protein, high-fiber mash. The mash is of poor quality for human consumption and is instead fed to ruminants; there is no process to extract protein from the mash. The preparation and storage of copra often occurs in unhygienic conditions, yielding poor quality oil that requires refining. A portion of the oil extracted from copra is lost to spoilage, to insects or rodents, and to the process of extraction.
Wet process
The all-wet process uses raw coconut rather than dried copra, and the protein in the coconut creates an emulsion of oil and water. The more problematic step is breaking up the emulsion to recover the oil. This used to be done by prolonged boiling, but this produces a discoloured oil and is not economical; modern techniques use centrifuges and pre-treatments including cold, heat, acids, salts, enzymes, electrolysis, shock waves, or some combination of them. Despite numerous variations and technologies, wet processing is less viable than dry processing due to a 10-15% lower yield, even compared to the losses due to spoilage and pests with dry processing. Wet processes also require investment of equipment and energy, incurring high capital and operating costs.
Proper harvesting of the coconut (the age of a coconut can be 2 to 20 months when picked) makes a significant difference in the efficacy of the oil-making process. Copra made from immature nuts is more difficult to work with and produces an inferior product with lower yields. Conventional coconut oil uses hexane as a solvent to extract up to 10% more oil than just using rotary mills and expellers. The oil is then refined to remove certain free Fatty Acids, in order to reduce susceptibility to rancidification. Other processes to increase shelf life include using copra with a moisture content below 6%, keeping the moisture content of the oil below 0.2%, heating the oil to 130–150°C (266–302°F) and adding salt or Citric Acid. Virgin coconut oil (VCO) can be produced from fresh coconut meat, milk or residue. Producing it from the fresh meat involves removing the shell and washing, then either wet-milling or drying the residue and using a screw press to extract the oil. VCO can also be extracted from fresh meat by grating and drying it to a moisture content of 10-12%, then using a manual press to extract the oil. Producing it from coconut milk involves grating the coconut and mixing it with water, then squeezing out the oil. The milk can also be fermented for 36–48 hours, the oil removed, and the cream heated to remove any remaining oil. A third option involves using a centrifuge to separate the oil from the other liquids. Coconut oil can also be extracted from the dry residue left over from the production of coconut milk.
RBD stands for "refined, bleached, and deodorized." RBD oil is usually made from copra (dried coconut kernel).
The dried copra is placed in a hydraulic press with added heat and the oil is extracted. This yields up practically all the oil present, amounting to more than 60% of the dry weight of the coconut.
This "crude" coconut oil is not suitable for consumption because it contains contaminants and must be refined with further heating and filtering.
Another method for extraction of a "high-quality" coconut oil involves the enzymatic action of alpha-amylase, polygalacturonases, and proteases on diluted coconut paste.
Unlike virgin coconut oil, refined coconut oil has no coconut taste or aroma. RBD oil is used for home cooking, commercial food processing, and cosmetic, industrial, and pharmaceutical purposes.
Hydrogenation
RBD coconut oil can be processed further into partially or fully hydrogenated oil to increase its melting point. Since virgin and RBD coconut oils melt at 24 °C, foods containing coconut oil tend to melt in warm climates. A higher melting point is desirable in these warm climates, so the oil is hydrogenated. The melting point of hydrogenated coconut oil is 36–40°C.
In the process of hydrogenation, unsaturated fats (monounsaturated and polyunsaturated fatty acids) are combined with hydrogen in a catalytic process to make them more saturated. Coconut oil contains only 6% monounsaturated and 2% polyunsaturated fatty acids. In this process, some of these are transformed into trans fatty acids.
Also see Bulk Oils and Fats and Fats and Oils
Applications
Used in the manufacture of margarine, milk and cream substitutes, soaps, cosmetics and synthetic detergents. Several tropical countries are using coconut oil as a ‘bio fuel’.
Shipment / Storage
Shipped in bulk and in drums. Goods liable to tainting should not be stowed in the same compartment. Coconut oil when shipped in bulk should only be carried in tanks which have been carefully cleaned prior to loading, otherwise it will become contaminated.
Shipped in bulk the oil solidifies at a temperature of approximately 17°C to 20°C according to the specific gravity of the oil itself, and unless particular care is taken to re-heat the oil prior to discharge gradually from 30°C, the loading temperature, to 50°C, the discharging temperature, damage may occur to the oil from two causes;
1) If sufficiently heated the oil will tend to solidify during discharge, causing discharge difficulties and possible loss in value of the oil.
2) If the oil is heated too rapidly and to a higher degree than that indicated it may scorc h, causing discolouration and loss in the saleable value of the oil, as it is possible than when the oil suffers discolouration it may not command the high price paid for the product when it is used in the manufacture of margarine. It is difficult to bleach discoloured oil, consequently it has to be used in the manufacture of soap or some other commodity. If the oil solidifies in the ship’s tanks, it cannot be liquefied again even by forced heating; in the vicinity of the heating coils, the oil melts, scorches, discolours and becomes rancid.
Phase changes: at 25°C coconut oil thickens, at 21 - 14°C it hardens and solidifies. The rate of heating should be no greater than 8°C/day. At approx. 24°C, the maximum duration of storage is about 6 months.
Drums used in the shipment of coconut oil may be either new or second-hand.
If on examination it is found that second-hand gasoline or oil drums have been used, this may explain the increase in the percentage of impurities in the oil to the drums not being sufficiently clean, and also increase the moisture content due to the drums not being properly dried before use. It is recognised that the commodity when shipped in drums may solidify when passing into cooler climates.
Risk factors
See Bulk Oils and Fats