Cooking oil pretreatment machine and different oil seeds
1.Cleaning: Cleaning is a series of operation to remove impurities in oil seeds.
2. Husking/dehulling/shelling: Oil seeds like peanut, sunflower seed, cotton seed, palm kernel, etc, have hard shells above nuts. Husking/dehulling/shelling is to seperate shells from nuts.
3. Drying: Reducing oil seed moisture to proper moisture is drying. Oil seeds might be harvested in rainy season with a high moisture, which leads drying to be essential for storage and further processes.
4. Crushing: Mechanical size reduction process is also named crushing. For big-size oil seeds, crushing reduces its size to benefit flaking, while for prepressed cake, crushing turns cake to proper size and creats better oil yeild for second press or solvent extraction. Crushing is always necessary for soybean, peanut, palm kernel, coconut copra, tung oil seed, etc.
5. Softenning: Softenning adjusts moisture and temperature of oil seeds, softens and increases plasticity of oil seeds. For low-oil-content oil seeds (soybean, rape seed/canola, cotton seeds, etc), softenning is an essential process for better flaking effect. For example, oil content of soybean is 18-22%, while soybean is hard, low-moisture and low-temperature, flaking will bring plenty of powders without softenning. However, this needs to be stressed that whether softenning is needed still depends on the properties of oil seeds.
6. Flaking: Flaking presses oil seeds from granulous to laminar, which brokes cell tissue of oil seeds and creats beneficial condition for cooking. Flaking also makes oil flows out smoothly when pressing or solvent extraction.
7. Puffing: Puffing turns oil seeds(cracked, flaked, or whole seed) to polyporous matters, which improves solvent permeability in extraction and increases leaching rate.
8. Cooking: Cooking is to wet, heat, steam and to cook flakes to change the internal structure of flakes, including destorying cells, protein solidification and denaturation, etc. All these changes makes oil easy to isolate and also enhance crude oil quality.
9. Pressing/prepressing: Pressing/prepressing is to press oil from oil seeds or cakes. In general, there are several oil press machine for this step.
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