Comprehensive Guide to Sunflower Seed Oil Extraction and Refining

Sunflower seed oil is a type of edible oil with high linoleic acid content, rich in vitamin E, carotene, and nutrients such as magnesium, phosphorus, sodium, and calcium. As consumer consumption continues to increase, the demand for diversified, healthy, and high-quality edible vegetable oils is becoming more apparent. Sunflower seed oil is considered a nutritious and healthy vegetable oil due to its rich content of polyunsaturated fatty acids, and it has become increasingly popular in the market in recent years.

There are many types of finished sunflower seed oil, including commonly seen pressed sunflower seed oil, solvent-extracted sunflower seed oil, high oleic sunflower seed oil, and aromatic sunflower seed oil, among others. Consumers have an increasing variety of options. The processing techniques of different types of sunflower seed oil are generally similar, with pressing and solvent extraction being the main methods used in oil plants for producing sunflower seed oil.

The pressing oil extraction process is a traditional edible oil processing method that uses physical methods and mechanical force to squeeze oil from the oilseeds. Depending on the production temperature during pressing, it can be divided into cold pressing and hot pressing processes.

Hot Pressing: This method involves steaming and frying sunflower seeds before pressing. The pressing chamber temperature is relatively high, and under high temperature and pressure, most of the oil in the seeds is released. The resulting edible oil has a good flavor and taste, retaining the natural aroma of sunflower seeds. Hot-pressed sunflower seed oil is more suitable for producing aromatic sunflower seed oil or flavor oil in small oil mills.

Cold Pressing: This method is carried out at temperatures below 60°C, without high-temperature treatment of the oilseeds. The entire process is simple, and fewer types of equipment are required. Since it does not involve high-temperature treatment, the pressed sunflower seed oil contains fewer impurities and requires minimal refining to meet the standards of healthy oil. It is a common process for producing high-quality and small-batch nutritious edible oil.

The solvent extraction method is an oil extraction process introduced from abroad, where oils that can dissolve the oil from the oilseeds are selected for processing. Solvent extraction of sunflower seed oil can control the residual oil in the meal to within 1%, resulting in high-quality sunflower seed oil meal. However, the oil contains a small amount of solvent and impurities, which need to be refined to reduce solvent content and remove impurities, thus meeting healthy oil standards.

In terms of quality, the edible oil produced by these three methods is ranked as follows: cold pressing , hot pressing , solvent extraction. Cold-pressed oil has minimal nutrient loss, fewer impurities, and is of high quality. Hot-pressed oil production may cause some nutrient loss, resulting in darker oil color, but the physical pressing process without chemical additives makes it relatively nutritious and healthy. Solvent-extracted oil requires refining before consumption; the deeper the refining, the fewer the impurities, but more nutrients are lost in the oil, making it slightly inferior in quality compared to the other two methods.