Process Flow of Low-Temperature Subcritical Extraction of Grape Seed Oil

Grape seed oil extraction methods include pressing method, organic solvent extraction method, supercritical extraction method, subcritical low temperature extraction method. The pressing method has low oil yield, high impurity content, and high temperature in the extrusion process, which destroys the unsaturated fatty acids in the oil; the ordinary organic solvent extraction method adopts high temperature desolvation in production, which destroys the unsaturated fatty acids in the oil, so that the nutritional value of the oil is greatly reduced. Our company adopts subcritical low-temperature extraction technology to extract grapeseed oil, which makes up for the shortcomings of the above production process.

The process flow of low-temperature subcritical extraction of grape seed oil mainly includes the following steps:

1. Raw Material Preparation: 

Collect grape seeds, primarily sourced from wineries as a byproduct of winemaking. After drying, separate the grape skins and stems to obtain pure grape seeds.

2. Pre-treatment:

 Remove impurities and foreign matter from the grape seeds to ensure purity.

3. Softening and Flaking: 

Soften the grape seeds and then roll them into flakes. The thickness and moisture content of the flakes are precisely controlled, typically maintaining a thickness of around 0.3mm and a moisture content of about 10%.

4. Low-Temperature Extraction: 

Send the prepared grape seed flakes to the extraction workshop, using subcritical butane as the extraction solvent. Multiple extractions are performed at room temperature using countercurrent extraction, usually three times, to fully extract the oil from the grape seeds.

5. Crude Oil Refining: 

The extracted crude grape seed oil undergoes a series of refining processes, including filtration, hydration degumming, deacidification, decolorization, deodorization, dewaxing, and fine filtration, to remove impurities and undesirable components, improving the oil quality.

6. Finished Oil: 

The refined grape seed oil is the final product, light green in color, with high quality and good antioxidant activity.

In the entire process, low-temperature subcritical extraction technology is a key step, which can effectively extract grape seed oil at a lower temperature while retaining the nutrients to the greatest extent. This process has the advantages of high oil yield, good oil quality and low production cost, and is suitable for large-scale production.