Complete Process of Edible Oil Refining: Why Dewaxing Is Essential for Sunflower Oil

Sunflower seed oil is a fat extracted from the seeds of sunflowers. In modern industrial production, the pre-pressing and solvent extraction method is predominantly used to obtain the oil, which is then further processed through refining equipment to produce high-quality finished oil. Common edible oil refining processes include deacidification, degumming, decolorization, and deodorization. However, an additional step—dewaxing—is introduced in the refining of sunflower seed oil. Why is this?

Wax is primarily found in the seed coats and germ of oilseeds, with sunflower seed oil containing 0.01% to 0.35% wax. Most of the wax in sunflower seeds is present in the hulls. If the hulls are not removed during crude oil extraction, the wax content ranges from 0.02% to 0.35%. In contrast, crude oil extracted from dehulled seeds contains only 0.011% to 0.015% wax. Waxes are lipid-like compounds composed of esters of fatty acids and monohydric alcohols. They have low solubility in oil and a high melting point, making them neither absorbable nor digestible by the human body. Additionally, wax crystallizes at low temperatures, adversely affecting the appearance of the edible oil. Therefore, dewaxing is necessary after the deodorization step in the refining process of sunflower seed oil.

Industrial dewaxing leverages the fact that wax precipitates at low temperatures. Various dewaxing methods exist, such as freeze crystallization, surfactant addition, cold agglomeration, electrostatic separation, and neutral winterization. However, freeze crystallization is currently the most widely used method in edible oil production. The dewaxing process involves transferring crude oil to a pre-cooling tank to lower its temperature, followed by cooling and crystallization in a crystallization tank. After crystallization, the mixture is aged to allow wax particles to form. The wax is then separated from the oil through cold filtration.

It is important to note that the temperature of the refining equipment must be maintained within an appropriate range during dewaxing. Excessively high temperatures may prevent sufficient wax precipitation, while excessively low temperatures can compromise the quality of the oil. Thus, the dewaxing temperature must be carefully set before production. Additionally, the duration of dewaxing significantly impacts the quality of the processed oil, directly affecting its color and transparency.

In summary, dewaxing is essential to ensure the quality of refined sunflower seed oil. However, the market offers a wide variety of dewaxing equipment, and selecting the right oil processing equipment is crucial not only for the quality of the refined sunflower seed oil but also for the investment cost and economic benefits of the oil mill. Therefore, oil mills must exercise caution when making their selection. Rather than opting for cheaper equipment from small workshops, collaborating with reputable manufacturers like Huatai Oil Machinery ensures better equipment quality and after-sales service!