Oil Processing Steps

In the entire oil processing plant, heat and chemicals methods are used to make the nutrients to be either converted or removed. Conversion to detrimental substances include trans fatty acids, polymers, cyclic compounds, aldehydes, ketones, epoxides, hydroperoxides, and other compounds not yet identified. Many of these substances are toxic, even in small quantities, so we have to seperate them out from the oils.

Below is the oil processing steps that you should follow in different oil processing stages.

Steps of Oil Processing Stages

1. Seed Preparation and Conditioning

Preparation of oilseeds usually start with heating and dehulling, then with chopping / grinding, rolling / flaking, apart from that a thermal or conditioning step is required. In addition, all oil seeds have enzymes that can influence quality. The object is to deactivate these enzymes early by means of heat. For successful pressing, the seed must be:

• Clean. Fine dust in the seed may clog the oil press hardware. Chaff left in the seed will absorb some of the oil and keep it from getting squeezed out of the expeller. Sand in the seed will wear out the press. Stones damage the oil press screw or piston.
• Dry. Moist seed leads to low yields and clogs the screw or cage, a part of the press. Moist seed may also get moldy, as mold spores are present in all crops. A rule of thumb is that the moisture content of the seed should be close to 10 percent. The number varies considerably for specific oilseeds. For example, rapeseed should be dried to a 7-percent moisture content, camelina to about 6 percent and sunflower to 8.5 percent. Safflower needs only to be dried to 11 percent and soybean is safe for storage and processing at 12 percent .
• Warm. Warm seed will yield the most oil for the least effort. The optimum heat range for oil extraction is from 100 to 160 degrees. There are several ways to preheat the seed in advance of extraction. For very small batches, heating the seed in an oven or double boiler works, as does concentrated sunlight in a solar food dryer or some other solar collector. For larger batches, a heating element in a hopper located between the seed storage facility and the oilseed press works well.

2. Oil Extraction

Oil extraction has quite a lot of methods.such as mechanical pressing, chemical extraction -  by mixing with such solvents as hexane and heptane. The primary objective of this step is to produce a clean, crude oil product. In some cases, after mechanical pressing, the oil is filtered and sold as unrefined oil, but more often, the oil undergoes further refining.

3. Refining, Bleaching and Deodorizing

RBD is not always beneficial to nutrition. Crude oil contains more vitamin E, trace elements, phytosterols and more. The trade-off is that crude oil is healthier but less stable Refining. Refining usually consists of two steps. The first step is degumming, which is described above. The second step is neutralization, in which the free fatty acids (FFAs) in the crude oil are caustic-stripped with sodium hydroxide (NaOH) in an aqueous solution. The resulting soap stock is settled, filtered or centrifuged out .

Oil Bleaching. In this step, the oil is mixed with certain types of bleaching clays to absorb colors and some other contaminants such as soap, trace metals and sulfur compounds.

Oil Deodorizing. This is a distillation process that occurs at high temperatures and low pressure. The oil is put under a vacuum and heated with steam to remove any leftover taste or odors and FFAs. Deodorizing can also be achieved by treatment with activated charcoal