Groundnut Oil Production Process: From Farm to Bottle 

The production of groundnut oil can be divided into two main phases: mechanical pressing and solvent extraction. Initially, mechanical pressing removes approximately 85% of the oil from the peanuts. The remaining oil is then extracted using the solvent extraction method. If using mechanical pressing technology, the oil production process consists of three key stages: preparation of peanuts, pressing, and refining of crude oil. The overall extraction process involves five steps: cleaning, dehulling, cooking, pressing, and filtering. 

The five steps of groundnut oil extraction 

1. Cleaning 

Objective: To remove impurities from the peanuts to ensure a pure, high-quality oil. 

Process:

• Initial arrival: Once harvested, peanuts arrive at the processing facility, where they may be mixed with other debris such as leaves, sticks, and weed seeds, and may include both shelled and unshelled peanuts. 

• Cleaning machine: The peanuts are fed into a cleaning machine, which uses a combination of air blowers, vibrating screens, and separators to remove dirt, stones, and other foreign materials. This machine sorts out the unwanted debris, ensuring that only clean peanuts proceed to the next stage. 

• Inspection: In some facilities, an additional manual inspection may be performed to catch any remaining impurities that automated systems might miss.

2. Dehulling 

Objective: To remove the outer shells of the peanuts, increasing the efficiency of oil extraction. 

Process: 

• Dehulling methods: The outer shells of peanuts, which do not contain oil and can reduce extraction efficiency, are removed. This can be done either manually, by hand, or more commonly, mechanically using dehulling machines. 

• Mechanical dehulling: The mechanical dehuller uses a series of rollers, friction surfaces, or abrasive materials to break the shells and separate them from the peanut kernels. This method is preferred for large-scale operations as it speeds up the process and reduces manual labor. 

• Benefits: Removing the shells before pressing increases the amount of oil that can be extracted, improves the efficiency of the pressing process, and reduces wear and tear on equipment. This also helps in improving the quality of the oil and the cake produced. 

3. Cooking 

Objective: To prepare the peanuts for pressing by breaking down cell walls and improving oil flow. 

Process: 

• Heating: The cleaned and dehulled peanuts are cooked to soften them and break down the cell walls that contain the oil. This process helps in making the oil more fluid, which aids in easier extraction. 

• Cooking equipment: The peanuts are usually heated in a cooker or roaster. Temperature and cooking time are carefully controlled to avoid burning and to optimize oil yield. 

• filtered groundnut oil: filtered groundnut oil is an excellent choice for this process as its purity and clarity ensure optimal oil extraction. The absence of impurities in double-filtered oil prevents gumming up the machinery and contributes to a smoother extraction process. 

4. Pressing 

Objective: To extract the oil from the cooked peanuts. 

Process: 

• Screw press machine: The cooked peanuts are fed into a screw press machine. This machine features a rotating screw that continuously pushes the peanuts through a chamber. 

• Pressure and heat: As the peanuts move through the chamber, pressure is applied, and friction between the peanuts and the machine generates heat. This heat reduces the viscosity of the oil, allowing it to flow more easily. 

• Oil and cake collection: The oil, now separated from the solid peanut cake, exits through one outlet while the remaining cake, which contains residual oil and solids, exits through another. The oil collected at this stage is considered crude and may still contain some impurities. 

5. Filtering 

Objective: To remove remaining impurities from the crude oil, ensuring a clear and pure final product. 

Process: 

• Filtration machines: After pressing, the crude oil is filtered to remove any remaining water, solid particles, and other impurities. This is typically done using filtration machines equipped with various filter media, such as mesh screens or filters. 

• Types of filtration: The filtration process may include several stages, such as coarse filtration to remove larger particles and fine filtration to eliminate smaller particles and contaminants. This ensures the oil is clean and ready for further refining or packaging. 

By following these detailed steps, the production process ensures that groundnut oil is extracted efficiently, maintaining its quality and purity for various culinary and industrial applications. 

Cost and production insights 

• The cost of setting up a groundnut oil production plant depends on the machinery and equipment used. For personalized advice on equipment selection and plant setup, you can contact industry experts. 

• Groundnut oil, with its pleasant taste and light color, is used in various culinary applications, including frying, baking, and making margarine and shortenings. 

• Peanuts, or groundnuts, have an oil content of 45-55%. The oil extracted can range from yellow to greenish-yellow in color. Groundnut oil is also used in animal feed. 

• India, the second-largest producer of peanuts after China, plays a major role in global peanut oil production. During the 2007-08 agricultural year, India produced about 35.99% of the nation’s total oilseeds. Typically, 2.5 kg of peanuts produce one liter of groundnut oil. The cost of producing this oil in India is around Rs. 225 per liter. 

Conclusion 

Groundnut oil is a versatile and valuable cooking oil with a straightforward production process. From cleaning and dehulling peanuts to cooking, pressing, and filtering, each step is crucial in ensuring the final product is of high quality. Understanding these steps can help appreciate the effort and technology involved in bringing this essential ingredient to your kitchen. And when it comes to choosing the best for your family, opting for double filtered groundnut oil can elevate your culinary experience. This extra filtration process removes impurities, resulting in a purer oil with a richer flavor and higher smoke point, making it ideal for various cooking methods.