Sc-CO2 extraction of fish and fish by-products in the production of fish oil and enzyme

Abstract

Supercritical carbon dioxide (Sc-CO2) is an alternative tool to extract lipid for the production of fish oil and enzyme from fish by-products (FBPs). In the application of Sc-CO2, this review covers sample preparation, lipid extraction operation, and characterization of fish oil and enzyme as final products. Generally, the fish samples with moisture content less than 20% and particle size less than 5 mm are considered before lipid extraction with Sc-CO2. Sc-CO2 parameters, such as pressure (P), temperature (T), extraction time (text), and flow rate (F), for simultaneous recovery of fish oil, protein, and enzyme were found to be less severe (P: 10.3–25 MPa; T: 25–45 °C, text: 20–150 min; F: 3–50 g/min) than the extraction of fish oil alone (P: 10–40 Mpa; T: 35–80 °C; text: 30–360 min; F: 1–3000 g/min). The enzyme from the Sc-CO2 defatted sample showed higher activity up to 45 U/mg due to lower denaturation of protein as compared to the organic solvent treated sample albeit both samples having similar pH (6–10) and temperature stability (20–60 °C). Overall, mild extraction of lipid from FBPs using Sc-CO2 is effective for the production of enzymes suitable in various industrial applications. Also, fish oil as a result of extraction can be produced as a health product with high polyunsaturated fatty acids (PUFAs) and low contamination of heavy metals.

Effect of Extraction Method on the Yield and Quality of Mullet Roe Oil

“…This is due to the ability of ethanol to extract higher polarity lipids. [24] Tempera-ture had also an effect in oil yield on SFE extraction yield (Figure 3), this is in accordance with previous studies on fish oil extraction. [24] EP extraction provided a similar recovery with SFE-E37.…”

“…[21,22] Traditionally, fish oil extraction has been performed by using large amounts of organic solvents with high extraction yields however, the separation of the solvents from the oil can be energy-consuming and induces the release of the hazardous waste stream into the environment. [21,23,24] Another widely used method for fish oil extraction on a large scale is wet reduction, during which the raw materials are cooked and pressed for oil recovery as well as hydraulic pressing. [22,23,[25][26][27] In wet reduction, a high temperature is usually applied, resulting in high energy consumption and degradation of some nutritional components of the oil whereas low extraction yield is observed.…”

“…[22,23,[25][26][27] In wet reduction, a high temperature is usually applied, resulting in high energy consumption and degradation of some nutritional components of the oil whereas low extraction yield is observed. [24,25,[28][29][30][31] Enzymatic hydrolysis of fish by-products has also been investigated, with lower cost and higher extraction yield and by making use of more modest operating conditions. [25,[32][33][34] Nevertheless, enzymatic hydrolysis would contribute to the hydrolysis, oxidation, and degradation of valuable compounds, such as PUFA and vitamins.…”

“…[28,31,33,34] SFE is a relatively new, innovative method that reduces the associated environmental impact and has been applied for fish oil extraction which induces high-quality fish oil as well as the reduction of toxic elements. [22,24,25,35] The main disadvantage of SFE is the high cost on an industrial scale, not only because of the high-pressure equipment applied, but also due to freeze-drying of the raw materials which is often used before SFE in order to reduce the moisture of raw materials. [21] Based on the above in order to produce high-quality fish oil on an industrial scale it is crucial the selection of the appropriate extraction method as well as the selection of the appropriate process variables.…”

Valorization of mullet roe by‐products for the production of polyunsaturated fatty acids rich oils

“…Supercritical fluids extraction (SFE) and especially with carbon dioxide (CO 2 ) has also been applied for oil extraction. This method reduces PUFA oxidation due to the extraction taking place under CO 2 environment and relatively low temperatures (Adeoti & Hawboldt, 2014; Jamalluddin et al, 2022; Pateiro et al, 2021; Rubio‐Rodríguez et al, 2012). Another method used mostly for fruit and seeds with high oil content such as walnut and palm fruit is pressing extraction (PE).…”