Guide to the CO2 extraction process of fish oil from sardine

Sardine

Sardine, also known as “sand mullet”, is a collective term for some squid. It is a warm-water fish in the offshore waters and is often distributed in low-latitude offshore areas. Chinese sardines are mainly about ten species of small sardines, with the highest yield of golden sardines and small sardines.

The composition of the sardine’s nutrients is: moisture 64.6%, protein 19.2%, fat 13.8%, carbohydrate 0.5%, minerals 1.9%. Compared with common marine fish, sardines have low moisture content and high protein, fat, and minerals. Among them, minerals include calcium, magnesium, zinc, manganese, etc., as well as protein and various vitamins. They are rich in pentanepentaenoic acid (EPA) and docosahexaenoic acid (DHA). )etc. These basic fatty acids help the blood flow in the body, maintain a healthy heart and prevent cardiovascular disease.

The extraction method of fish oil from sardine

At present, the extraction status of these lipid nutrients in various fish species is still high in cost, low in yield, and high in waste.

The use of traditional methods leads to waste of resources and low yield, while supercritical extraction uses high yield and good texture, although the cost will increase, supercritical co2 extraction will certainly be the mainstream way of fish oil extraction in the future.

Therefore, the extraction of sardine fish oil by the supercritical fluid extraction method has potential value and prospects for the deep processing and comprehensive utilization of sardines.

CO2 extraction technology of fish oil from sardine

At present, the extraction status of these lipid nutrients in various fish species is still high in cost, low in yield, and high in waste.

The use of traditional methods leads to waste of resources and low yield, while supercritical extraction uses high yield and good texture, although the cost will increase, supercritical extraction will certainly be the mainstream way of fish oil extraction in the future.

Therefore, the extraction of sardine fish oil by the supercritical fluid extraction method has potential value and prospects for the deep processing and comprehensive utilization of sardines.

Advantages of supercritical CO2 extraction

Supercritical fluid extraction (SFE) is a new separation technique that extracts oil from fish raw materials by using a fluid in a supercritical state as an extractant.

Compared with traditional chemical methods, it has the advantages of high separation efficiency, low operating temperature, good product quality, and no environmental pollution. However, the investment cost is high, and the method is only used when the product requirements are high.

The CO2 extraction process of fish oil from sardine

  • Extraction temperature: 40 ° C;
  • Extraction time 3 h;
  • Extraction pressure 2900 psi;
  • Fish oil yield under this condition is 0.3246%.

Steps

Selection of sardines – crushing – refrigeration – drying – weighing charge – supercritical extraction – obtaining fish oil

Three Factors Affecting CO2 Extraction Process Efficiency

Extraction pressure

In the single factor experiment of supercritical extraction, the effect of extraction pressure on the extraction rate was investigated. The extraction temperature was 37 °C, the extraction time was 2 h, the CO2 flow rate was 15 mL/min, and the extraction pressure was 2600-2800 psi (1 MPa ≈ 145 psi).

That the extraction rate of sardine fish oil has a maximum value with pressure change, that is, it reaches a maximum at about 2800 psi, because the temperature is constant, the supercritical extraction pressure is increased, and the density of supercritical CO2 fluid is increased. The solubility capacity increases, so the extraction rate increases with the increase of pressure. After the pressure is stronger than 2800 psi, the extraction rate decreases because the viscosity of CO2 fluid increases, and the mass transfer rate decreases as the extraction pressure increases, resulting in a decrease in extraction rate.

Therefore, the appropriate pressure for extraction is around 2800 psi.

Extraction temperature

In the single factor experiment of supercritical extraction, when the effect of temperature on the extraction rate was investigated, the extraction time was kept for 2 h, the extraction pressure was 2900 psi, the CO2 flow rate was 15 mL/min, and the extraction temperature was 35-44 °C.

When the extraction temperature is raised to 38 °C at 35 °C, the extraction rate is significantly improved, indicating that the effect of temperature on the CO2 diffusion coefficient and the increase in the solubility of the extract is stronger than the adverse effect of the decrease in the density of the CO2 fluid.

When the temperature is raised from 38 ° C to 44 ° C, the extraction rate decreases with increasing temperature, because the elevated temperature dominates the adverse effects of the decrease in the solubility and density of supercritical CO2, and thus the extraction rate decreases. Therefore, the extraction temperature is suitable for a temperature of about 38 °C.

Extraction time

In the single factor experiment of supercritical extraction, the effect of time on the extraction rate was observed. The extraction temperature was 38 °C, the extraction pressure was 2800 psi, the CO2 flow rate was 15 mL/min, and the extraction time was 1.5 h, 2 h, 2.5 h, 3 h, 3.5. h. Supercritical extraction time is a major parameter in the extraction of sardine fish oil.

The extraction time is too short, the extraction process of raw materials can not be completed completely, the extraction effect is poor, and the extraction time is too long, which is equivalent to using a large amount of energy consumption and logistics loss in exchange for microextraction. The effect is improved. The experimental results show that the suitable extraction time is about 3h.

Orthogonal experiment

Based on the previous single factor experiment, the main influencing factors affecting the extraction rate of sardine fish oil were extraction temperature, extraction time, and extraction pressure. The optimal process obtained by the orthogonal experimental results table increases the extraction rate from 0.2846% to 0.3359% under the condition of changing the time parameters, and the growth rate is the fastest at 2.5h-3h, so it can be an orthogonal experiment and auxiliary experiment. The optimum conditions for supercritical CO2 extraction of sardine fish oil were determined: dynamic extraction, pressure 2900 psi, extraction temperature 40 ° C, extraction time 3 h, extraction rate 0.3246%.

  1. The sardine fish oil can be extracted by supercritical CO2 extraction, and the sardine fish oil is a fishy, transparent, pale yellow oil.
  2. Single-factor experiments showed that the optimal process conditions for supercritical CO2 extraction of sardine fish oil were as follows: extraction temperature 38 ° C, extraction time 3 h, extraction pressure 2800 psi.
  3. The orthogonal experimental results show that the optimum conditions for supercritical CO2 extraction of sardine fish oil are: extraction temperature of 40 ° C, extraction time of 3 h, extraction pressure of 2900 psi; fish oil yield under this condition is 0.3246%.