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.
Methods of kiwifruit seed oil extraction
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%)
- Mechanical pressing (20.0%).
- The extraction rate of mechanical pressing method was the lowest, only 20.0%, and the 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 CO 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;
Advatages of supercritical CO2 extraction kiwifruit seed oil
The extraction rate is high, the selectivity is good, and there is no solvent residue by supercritical CO2 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.