Rice bran oil is extracted using a process that involves preparing the rice bran and then using solvent extraction. Here's a breakdown of the steps:
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Rice Bran Preparation:
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Stabilization: Fresh rice bran contains enzymes that can break down the oil, increasing free fatty acid content and reducing oil quality. To prevent this, the bran is stabilized. This is often achieved through heating (like puffing or extrusion) to deactivate these enzymes. This process also helps to rupture oil cells, improving extraction efficiency.
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Moisture Adjustment: The moisture content of the rice bran is adjusted to an optimal level for efficient oil extraction.
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Flaking (Optional): The stabilized rice bran is often rolled into flakes. This increases the surface area exposed to the solvent, improving the efficiency of the oil extraction process.
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Solvent Extraction:
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Hexane: The prepared rice bran is then treated with a solvent, typically commercial hexane. The hexane dissolves the oil from the bran. This is done in a specialized extraction unit.
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Miscella Recovery: The mixture of hexane and oil, called "miscella," is then separated from the spent rice bran.
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Solvent Removal: The hexane is then removed from the miscella through distillation and evaporation. The recovered hexane is recycled for further extraction. This leaves behind the crude rice bran oil.
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Refining:
- Degumming: Crude rice bran oil contains gums (phospholipids) which are removed.
- Neutralization: Free fatty acids are removed to improve the oil's stability and flavor.
- Bleaching: Color pigments are removed to improve the oil's appearance.
- Deodorization: Volatile compounds that cause undesirable odors and flavors are removed by steam distillation.
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Blending & Packaging:
- The refined rice bran oil can then be blended with other oils or additives as needed for specific applications. Finally, the refined oil is packaged for sale.
In summary, obtaining oil from rice bran involves stabilization to prevent degradation, solvent extraction using hexane, and then refining to produce a high-quality oil suitable for consumption and other applications.
