Groundnut oil has attained the status of cooking medium of choice due to its embedded health benefits. Apart from its alluring strong aroma and universally liked peanut flavor, the all-purpose cooking oil brings multiple health benefits to the table. By being an active agent in lowering cholesterol and especially the bad cholesterol, it is being accepted gleefully across the globe. The benefits include a low content of saturated fat that is naturally free from cholesterol and trans fat. It is further blessed with high unsaturated fat while being a good source of phytosterols and vitamin E. With an assured market and greater possibility of returns, setting up a groundnut oil manufacturing plant for Groundnut oil refining today makes eminent sense.
Crude Groundnut Oil Composition
| S.No. | PARTICULARS | PARAMETERS |
|---|---|---|
| 1. | Free Fatty Acid (as oleic acid) | 1 – 2% |
| 2 | Iodine Value | 86 – 107 |
| 3. | Saponification Value | 187- 196 |
| 4. | Unsaponifiable Matters | 0.4% apx. |
| 5. | Titer | 26 — 32°C |
| 6. | Smoke Point | 226°c apx. |
| 7. | Specific Gravity | @ 20°c 0.912— 0.92 |
Fatty ACID Composition :
Alkali Refining of Groundnut Oil
Objectives of refining
- Removal of undesired products from crude oils.
- Free fatty acid s (FFA)
- Phospholipids (gums)
- Oxidized products
- Metal Ions
- Colour pigments
- Others
- Preservation of valuable vitamins. (Vitamin E or Tocopherol – natural antioxidants)
- Minimize oil losses
- Protection of the oil against degradation
Methodology of Refining
Groundnut oil is usually refined by alkali neutralization process.
For alkali refining following processing step takes place:
- Gums conditioning & Neutralization
- Bleaching
- Deodorization
Alkali Refining Process
- Gums conditioning & NeutralizationGroundnut oil first treated with citric acid and followed by caustic soda lye to neutralize the fatty acids and conditioning of phospholipids. Neutralization reaction produced the sodium salt of fatty acids which removed through centrifugal separator and clean oil washed by hot water to remove the traces of soap.
- Washing Neutralized oil treated with hot water and separated through centrifugal separator to remove the traces of soaps from neutral oil.
- Drying Removal of moisture under vacuum.
Bleaching of Groundnut Oil
“Bleaching” is a process of selective removal of pigments and impurities by the physical and chemical interaction of an adsorbent with an oil or fat to improve its quality.
This process refers to the art of removing-
- Color pigments
- Dirt, Trace metals
- Removal of polycyclic Aromatic compounds
- Phospholipids
Airox Nigen provides wet bleaching process in its Groundnut Oil Processing Plant which has shown better results with lesser amount of bleaching clay.
Deodorization of Groundnut Oil
Deodorization of Groundnut oil is a vacuum stripping process in which a given amount of a stripping steam is passed for a given period of time through hot oil at a low pressure which removes various volatile components and fatty acids to increase the self-life, and maintained the good odour free test of product.
Deodorization is a Multi-Step Process Comprising
- Deaeration
- Heating
- Deodorization cum De-acidification
- Cooling