Malaysia and Indonesia is the first two countries in the world planting large acre palm trees. Palm oil and palm kernel oil have sprought rapidly in edible oil market in recent years. Palm kernel oil contains more unsatuated fatty acid and has high iodine number. Except for cooking, it can be divided into solid state and liquid state through crystallizing and pressing. The solid oil can be the replacement of cocoa butter while liquid one is used for baking, hydrogenating or making soap.
Palm Nut Pretreatment
Palm kernel pre-treatment is indispensable to get pure palm kernel oil; more important,the clean palm kernel is favor to protect oil press and extend its working life.
a.Vibrating screen is used here to sieve sand, stones and other debris; at the same time, magnetic separators are adopted to separate metal debris. b.A hammer grinder is necessary to break the whole palm kernel into several pieces. c.The kernel pieces are fed in a roller mill for powder. The palm kernel cake thickness becomes thinner and thinner as it drops from the top to the bottom ,about 0.25 to 0.4 mm thick. d.The kernel flakes are then conveyed to cooking to adjust the moisture content and ensure pure oil.
The pretreated palm kernel material is then transfered to the screw oil press for extraction. Equipped with automatic temperature-controlling device and crude oil filter tank, Our screw oil press operates easily and has high oil output After pressing, the crude palm kernel oil is filtered through the filter cloth and stored in tanks temporarily, when the de-oiled cakes are discharged out. One more thing that the feeder is not just a common feeder but specially designed which ensures the feeding continuously and averagely; thus the pressing process is smooth and efficient.
Like other oil seed refining process, palm kernel oil refinery has to follow four steps which are degumming, neutralization, decoloring and deodorizing.
At degumming section, hot water is used here as materials like phospholipids and gums are soluable in oil but not in water.Thus the impurities are separated. Some of them are made into lecithin or added to cakes for flavor. Degumming can improve palm kernel oil edibility and extend storage time.
Neutralization is also known as deacidification. Alkali is the main material to neutrulize free fatty acids and convert it to soaps which are removed away under centrifugal force.
At the decoloring stage, bleaching earth or clay is added to the crude palm kernel oil and heated. The oil is mixed with bleaching earth and keep the mixing and reaction continuously. After decoloring, the bleached oil should be filtered to remove residues created in this step.
Palm kernel oil deodorization is the last but not least stage in oil refinery.The bleached oil is deaerate and heated and deodorized in high pressure. After going through the heat exchanger, the deodorized oil should be cooled and filtered. The free fatty acid is collected as by-products.
Palm kernel oil's wide market share in edible oil industry raises an urgent claim on edible oil processing crafts. Although the pressing techniques are close to be mature, we still should pay attention to the advanced techniques and endeavor to offer people purer palm kernel oil.