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Supercritical CO2 Extraction of Kiwifruit Seed Oil

Supercritical CO2 Extraction of Kiwifruit Seed Oil

 

The content of kiwifruit seeds is about 0.8-0.12%. The dry seeds are yellowish-brown or brown with bright color. The 1000-grain weight is 1.2g-1.6g. Kiwifruit seeds are rich in crude fat, crude protein, VC, VE, carbohydrates and minerals such as calcium, potassium and selenium.

Supercritical fluid Extraction Machine
Supercritical fluid Extraction Machine

Common methods of vegetable oil extraction include mechanical pressing, organic solvent extraction, supercritical extraction, etc. Pressing method and organic solvent method are used less and less because of their respective shortcomings. Supercritical fluid extraction (SFE) technology is commonly used in kiwifruit seed oil extraction. It has high extraction efficiency and no residual organic solvents. It can reduce the loss of nutrients in the extraction process of kiwifruit seed oil.

The extraction rates of the three methods were as follows: supercritical CO2 extraction (28.3%), solvent extraction (26.9%) and mechanical pressing (20.0%). The extraction rate of mechanical pressing method was the lowest, only 20.0%, and the residual oil rate of cake was 9.2%.

The physicochemical constants and fatty acid composition of kiwifruit seed oil obtained by mechanical pressing, solvent extraction and supercritical C O 2 extraction are basically similar, but the acid value of kiwifruit seed oil obtained by mechanical pressing is obviously higher, and the quality of oil is lower than that of kiwifruit seed oil extracted by other two methods. The traditional mechanical pressing method has high residual oil content, low oil yield and high energy consumption; although the extraction rate of organic solvent extraction method has been greatly improved, the solvent residue in the product is difficult to control, the extraction process is long and the operation is complicated; the extraction rate is high, the selectivity is good, and there is no solvent residue by supercritical C O 2 extraction. No pollution, not only can overcome the shortcomings of the traditional process, but also the process is simple. The purpose of extracting kiwifruit seed oil can be achieved by controlling the main parameters such as pressure and temperature. In addition, supercritical CO2 extraction is extracted at low temperature, which can avoid the thermal degradation of kiwifruit seed oil at high temperature and protect the activity of physiological active substances. Therefore, the supercritical CO2 extraction method is more suitable for the extraction of precious oils such as kiwifruit seed oil.

In supercritical fluids, CO2 is the most commonly used organic extractant because of its low critical pressure (7.38 MPa) and critical temperature (31.3 C). Using SC-CO2 as solvent to extract vegetable oil has the following advantages and characteristics compared with traditional oil extraction technology: 1) CO2 is a non-combustion, non-toxic, resource-rich, easily available, cheap and environmentally friendly solvent, which has production safety, and SC-CO2 has high diffusion and solubility. (2) Good selectivity. The solubility of CO2 can be controlled by adjusting temperature and pressure, so as to selectively extract the target product, reduce impurities and enrich the effective components of the target product, improve the product quality and appearance, and the process is simple, time-saving and labor-saving, with less pollution from three wastes. (3) CO2 is a gas at room temperature and pressure, and there is no residual organic solvent in the product. (4) Low temperature operation can protect the physiological activity of active substances and obtain products with stable active ingredients and high quality. Protein components can be well protected in the extraction process of vegetable oil, which is beneficial to the utilization of protein. _The oil obtained by SC-CO2 contains less phosphorus and has light color, so degumming and decolorization can be omitted after treatment. Most free fatty acids can be removed through process adjustment, thus eliminating acid removal steps, which not only simplifies the process, but also avoids the loss of nutrients in the refining process.

supercritical co2 fluid extraction equipment